Top 125 places Air-cooled vw engines leak oil

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How many places can air-cooled vw engines leak oil? A lot more places than the most exotic Ferrari engine ever made to date. And just a few more than a Porsche 911 engine. And realize – many gaskets – pushrod tube seals for instance, can leak on either side and in the middle and through itself if it’s cracked. So one tube seal can leak in any one or all of any combination of four places. There’s supposed to be two gaskets and one metal oil deflector plate between these two gaskets under the generator pedestal so, with respect to the previous

sentence, that makes 6 sides of possible leakage at the generator pedestal. So if you think I’m splitting hairs in the following list, think again. And I probably forgot a few. Some apply to transmissions and anything else that has oil in it.

Type I, Type III

125. Top sump plate gasket.
124. Bottom sump plate gasket.
123. Sump plate drain plug gasket.
122. Drain plug stripping (marginal threads causing oil to leak using threads as passage). Most likely with a fake plug or sump plate.
121. Drain plug w/used copper sealing ring.
120. Drain plug with a new or used plastic sealing ring ala a quickie oil change place, or an auto repair shop that “works on everything”.
119. A just plain loose drain plug
118. Any sump plate stud due to stripping or no copper ring or just loose.
Use stepped studs to fix, not helicoils. Click here for instructions on how to fix stripped sump studs …  Unless you must use the orig cap nuts, use normal nuts. Cap nuts often grab the thread, pull
the stud out and forever it becomes a bolt (until you correctly install a stud but now the stud is loose and turns when you tighten the nut and that’s why you need to use a stepped stud using the proper method of installation and there is one) but the aluminum is not meant to have bolts screwed in and out of it often – it will strip
pretty quick – meaning after not so many oil change in and out screwing sessions. The only place I’ve seen a bolt that screws into and out of a hole in aluminum is on
Vanagon water cooled engines and a few places on later (beginning with mid-seventies) air cooled transmissions. It’s just not a good idea so they very seldom do
this. Never, unless absolutely necessary, replace a stud with a bolt on any aluminum automotive part – especially an air cooled VW. And since there’s 6 studs …
117. See 118.
116. See 118.
115. See 118.
114. See 118.
113. See 118
112. Oil pressure relief valve.
111. Oil pressure control valve (at front of case, if so equipped).
110. Oil pump inner gasket.
109. Oil pump outer gasket.
108. Oil pump stud/nut/pump interface(between threads and between pump cover and the stud themselves). Since there’s 4 studs, we’ll call this leak number 15-18.
Use torn off inner oil pump gasket corners to make gaskets to put under the washers for the nuts that hold the pump down. Use sealant too. And even though the book says not to, use sealant (Gaskacinch) even on the outer thin pump cover gasket. The book says not to but VW did it – they came like that outta the factory. I think they said that just to make sure nobody filled the pump with glue. Realize manuals get into the hands of people with quesionable skills so I think manuals are not only published to help you fix your car – they also protect some of you from yourself (like torque values and very strong arms).
107. See 108.
106. See 108
105. See 108.
104. Behind the crank pulley – usually due to excessive blow by. Volkswagen used to supply these pulleys with an oversize oil return hub to help cure leakage problems
due to too much clearance between the hub and the case. Incidently – when installing any crank pulley, always push it in a little and check to make sure the
engine turns, push it in a little farther, check again and so on. You don’t want to jam a pulley that doesn’t really fit into your case and damage the bore. Then
you’ll really have a leak. And don’t assume a sand seal will fix the a leak here. They won’t last long re keeping the area leak free and there’s a reason they call
them sand seals – they keep sand a out alot better than keeping oil in. Only as a last resort is a sand seal a viable solution. It’s really just a band aid for the most
likely problem – worn rings. The thing is, since the engine is not designed for a seal, there’s really not enough room to put a seal with a wide enough lip that will
maintain elasticity for a reasonable amount of time. Being very narrow lipped, they just can’t take too much heat and none that I’ve seen are made out of
very heat resistant red silicone like a flywheel seal that gets just as hot but lasts a real long time.
103. Dipstick. Reason? As above – too much blowby. Take out the dipstick while the engine’s running. Place the palm of your hand a few inches away,
facing the dipstick tube and rev the engine. If your hand gets soaked with oil pretty quick. you’ve either got a plugged breather hose or a blowby problem.
102 Oil pressure switch – not tight enough or the wrong one. One way it can be the wrong one is because sometimes you’ll get one for a water cooled VW
without tapered (as they should be) threads and it won’t self seal right with a non-tapered thread unless you bottom it out and use a gasket. The proper tapered
threaded switch is the only way to get a perfect seal.
101. All oil pressure switches eventually leak between the plastic center and the metal body of the switch.
100. Distributor “O” ring. Put a new one in if your old one is flattened to the point where it’s flush with the sides of the slot it fits into. If the distributor wiggles a lot
in the bore it fits into on the case, it can leak too. Very unlikely except the new copies of the 009 distributors are slightly smaller in diameter than the real thing
and they wiggle a lot. If you’ve got on of these distributors, the “O” ring my never make a positive seal. But hopefully so since that’s all there is.
99. Sometimes distributors leak between the rotating shaft in the distributor and the body of the distributor. Oil travels from the engine right up the
distributor shaft and into the distributor. You’ll end up with oil in the cap, on the points and drippng out of the bottom of the distributor body.
And any oil or grease on the contact surfaces on the points will eventually cause them to fail.
98. Left side of the case (crack) or a porosity leak (oil leaks right through the case with no visible sign of a crack or hole). Or it may be due to a poor casting.
I’ve seen a leak like this in one of the new aftermarekt aluminum cases with a visible casting flaw. I tapped it, put a small screw in it and put a lot of epoxy
on top. This was a brand new case. The hole was on top of the right side of the case. No effect on anything due to this fix other than stopping the leak.
97. Right side of case – crack or a porosity leak with or without a visible reason for leak. Porosity leaks? The oil just comes right through the metal like a very bad entity
coming right through a solid wall in a Stephen King novel. Cracks ? – you can see those.
96. Both case halves have a bunch of plugs. They seldom come loose however there’s a couple at the oil pump end than can become detectably loose since they
screw in. You should check them for looseness and if they’re are, use a chisel and a hammer to try to turn them tighter. You won’t be able to use a screwdriver
because you can’t get enough leverage to tighten them with a screwdriver. Count the plugs on your case, subtract one from the amount and add that to the total
of this list and that’s the absolute grand total of how many potential places a VW engine has to leak. Except for a few others we haven’t even thunk of yet.
95. Oil cooler – seldom happens but sometimes they do.
94. The mounting tab on pre-dog house coolers often breaks leaving cooler with only the two studs holding it down thus making it stand less than square
with respect to the case causing poor sealing at the two potentially good seals. You can fix this with brazing. If yours isn’t broken, braze the tab to reinforce it thus
making breakage much less likely.
93. Oil cooler seals between cooler and case.
92. As above (there’s two seals).
91. Between cooler and cooler mount (doghouse).
90. As above, there’s two seals.
89. Fuel pump top gasket.
88. Fuel pump bottom gasket.
87. Fuel pump bakelite. They crack
86 Between the shaft in the fuel pump and the hole it sticks out of in the body of the pump. This is the shaft that the lever in the pump swivels on.
85. Fuel pumps often have a small hole near the bottom that’s a drain for any fuel that reaches the bottom of the pump diaphram to drain out of. Sometimes
oil gets up there and the oil leaks out of the pump via the hole.
84. Left valve cover gasket.
83. Right valve cover gasket.
82. Lower cylinder head nuts – leaks from under the washer and out though the hole it’s respective stud goes through in the head. Since there’s a total
of 8 lower studs/nuts …
81. See 77.
80. See 77.
79. See 77.
78. See 77.
77. See 77.
76. See 77.
75. See 77..
74. Between the rocker hold-down stud threads and the head. Even with a new “O” ring, use sealant.
73. See 69.
72. See 69.
71. See 69.
70. Upper and lower cyinder head studs with through holes in the case. A blind hole is a hole you can’t see through. Some head stud holes are blind,
some you can see through, hence the name “through holes”. Use Locktite all of them. It’ll keep them from coming loose and prevent leaks
between the threads of the through holes and their respective studs. The new cases with factory inserts (for 8mm head studs) sometimes leak
around these inserts. Granted, they don’t leak much – mostly minor seepage if they leak at all. If you want to eliminate their leak potential, you’ll
have to find a willing machinist to attempt to remove the ones in through holes, forget about it (recommended), or remove them and put different inserts
for 10mm head studs. You’ll need to drill and tap each hole to do this. Most used cases have had the 10mm inserts installed a long time ago.
I’d never take any insert out for the sake of trying to achieve perfection re leakage. But if you don’t have inserts, have them installed. Use Locktite.
Never build any type I engine without inserts. Studs with no inserts are pretty much guaranteed to strip eventually. And with all the drilling and tapping
required to install them, you must disassemble the entire engine to put them in. And here’s a thought – if you had ten old cases and one didn’t have
inserts, the one without inserts is probaby the best case in the pile. Lowest mileage? Maybe. Least align bored? Probably. Think about it. One more
thought on inserts. The best kind is probably the one called “TimeSerts”. Now there are 16 head studs so you need 16 inserts, right? NO!! Factory
installed inserts for 8mm head studs (the only kind VW ever installed inserts for – they came with these in brand new VW’s and come in all
new cases). They use 16 in each case. Including the so-called “deep stud” – the upper cylinder head stud closest to number three cylinder exhaust
valve. These 8mm inserts require a smaller hole than 10mm heads studs.

As a convention, we’ll call this “the number 3 stud. This is the thing: VW cases, in 1969 for instance, crack. The crack I’m talking about
is roughly vertical and is visible (when it occurs) right behind the flywheel on the drivers side case half just below (actually, to the left of the bottom of the hole
as you’re looking from the flywheel side of the case) the lowest point of the hole that the number 3 exhaust stud screws into.

(A side thought: this crack often “bisects” the hole that an oil galley plug is pressed into. When this happens, the plug can fall out instantly and if your engine’s warmed
up and you’re moving fast enough, by the time you find out you’ve got no oil, your engine’s toast).

So think – the number 3 stud is literally pulling the case apart and causes the crack. What VW began doing, I believe it was in
1970, was to drill the hole in the case for the number three stud deep enough so than rather than using the standard number 3 stud with respect to
length, they drilled the hole so deep, the proper stud for it is the same length as a bottom head stud. Why? Because now, the threads in the hole in
the case are below (with respect to the surface) the place where the case cracks so it’s pulling the area together rather than pulling it apart, and, in the VWengineer’s minds, preventing
the case from cracking. Thes first deep-stud case had 10mm head studs and no inserts. So why only 15 inserts, instead of 16? You want your machinist to drill the number 3 stud deep enough to use a lower head stud

but don’t put an insert there. Just drill and tap the exisiting aluminum. It’s the bottom head stud case holes that usually strip – not the top ones (unless the
driver of the vehicle has been driving it with really loose heads for a long time, top ones seldom strip. Lotta vibration here and the heads just trying to fly off the motor. This takes a
toll on the threads in the case. That’s why you don’t just do the bad ones or just the bottom ones – you do them all. Except for the number 3 stud. It’s unlikely
it’s ever going to pull and even if the existing threads are stripped, you’re gonna drill the hole over an inch deeper and tap new threads anyway so no biggie.
But the reason for not using an insert here – why take metal away from an area that’s a common place for cracking. Plus, with an insert for 10mm head studs
makes for a pretty thin wall thickness between the hole and the flywheel side of the case. I was putting an engine together with an insert in the position. I didn’t
like it was either replace the case or use it. There was nothing wrong with it other than I wished it didn’t have an insert there. I was putting the driver’s side head
on and the stud stripped. Once you strip the hole for a 10mm head stud, you throw the case away. I had to find another case. So there’s two reasons for not
putting an insert there – you don’t need it and it might strip. The preceding does not apply to cases with factory 8mm studs and inserts.

And … if you find yourself with a real nice old case with no inserts, don’t let anyone talk you into putting the number 3 one in after I just spent the minumim
amount of words necessary to hopefully very clearly explain to you why you shouldn’t put an insert there. To be succinct – there’s not enough room for it to be reliable
and you don’t need it anyway!! And there’s nothing worse than an insert installation manager induced crack (meaning engine builder who told the machinist to do it or
letting him do it ’cause you – the builder – can’t talk him out of it) in the case (ie – don’t say I didn’t warn you!).

Seems like a lot more than just leak talk but the head studs hold the heads on. You want them to be right. They hold the pushrod tubes snug, the head/cyl
interface is sealed by the head studs and likewise the cylinder base/case interface. Nice tight heads and bulletproof head stud anchoring make for a
long lasting engine. As do the nuts and bolts that hold the case together.

And since their’s 8 through holes for the head studs in the case …

69. See 70
68. See 70.
67. See 70.
66. See 70.
65. See 70.
64. See 70.
63. See 70.

62. Oil cap gasket. The cap shouldn’t wiggle. They came new with cork gaskets. Sometimes caps fit loosely – you can often fix one up with a cracked
gasket by replacing the gasket or the cap. The gasket should be cork, not rubber.All oil cap area moisness/leakage problems are a result of crankcase pressure, aka blowby. All engines, new or old, have some
blowby. If you take off the cap with the engine running, place your hand a few inches from the hole where the cap was, you shouldn’t get much oil thrown
at your hand, you’ve got negligible blowby. If your hand’s soaked, you’ve probably got a problem.
61. Sometimes the cap gasket is okay looking but the cap’s loose – it wiggles when it’s “tight”. Add one more gasket so you have two. If you have a rubber gasket, put it
behind the cork one or use two cork ones or just make a second out of gasket material available at any auto parts store.This fills the gap and
then the cap’s nice and snug. As it should be. Make sure it’s easy enough to turn so it’s practical. New cork gasket are available through many VW parts
suppliers.
60. Breather hose from oil filler area to air cleaner. Use nice braided German hose for this. They’re usually gooey but it’s gotta be there. Don’t plug this up.
Imagine a box that’s a ten foot cube shape. Put a guy with an excercise bike in the box and put three feet of oil in it. Now make him pedal. He’s gonna
splash the oil around and create internal pressure. In other words, if there was small a hole in the top of the box and you put your hand over it, you’d
feel a weak breeze. If he stops pedaling, the breeze stops. The pistons make breeze along with the spinning crank and rods.This is why there’s a breather outlet on the
engine. If you plug it, anyplace there’s a poor
seal on the engine will become the new breather outlet. The first, and hopefully last place (since you’ve fixed your breather by now), is right behind
the crank pulley because there’s no seal there – just the oil return threads on the pulley hub so it’s wide open to the outside of the engine so it’s the path of least resistance. Since it’s low with respect to oil level, it leaks not just breeze but liquid oil. If you plug the breather and just drive a block or two, you’ll instantly have oil spewing right there at the pulley. The best way to route that hose is as it was new – to the air cleaner because with air cleaner mounting, it’s sucking the air right out of the case, helping it breath very effectively. This reduces the risk of many pesky leaks, especially behind the
crank pulley and out the dipstick tube. And perhaps making it so your clutch lasts just long enough to get to the next town being that the flywheel seal is
just about ready to spew big time and the benefit from your properly installed breather hose was just enough to prevent the seal from soaking the clutch fifty
miles earlier out in the middle of nowhere making the car undriveable leaving you stranded in a very, very undesireable place.
59. Flywheel seal. ONLY USE THE NICE RED ONES.
58. Flywheel “O” ring. Most people think the flywheel needs to be replaced each time they put a clutch in, for instance. After all, if this seal leaks, you
get oil on the clutch and it makes it slip. True. But this takes time. This oil leaks behind the flywheel. It takes quite a while before the air being
blown around by the rotating mass (flywheel, pressure plate, and maybe the disk has an effect too) to get that swirling oil mist actually on the clutch
disc thus making it slip. This seal keeps oil from passing between the flywheel hub that he seal contacts and the seal itself. But the “O” ring
prevents oil from passing in between the end face of the crank and then between the dowel pins and the dowel pin holes in the flywheel. Leakage here
provides a direct route right to the clutch disc and slippage starts real fast with this leak. To prevent this, always use red Locktite here. Put the “O”
ring in the previously sterilized flywheel face (meaning clean w/zero oil residue of any kind). Make a ring of locktite just inside the “O” ring after it’s intalled
and a little ring of Loctite around each dowel pin hole and join those Locktite rings with a line of Locktite drawn between each dowel pin hole to the other.
Now it won’t leak. And, curiously, this will even work with no “O” ring or when all you have is the old one because you just ordered the seal and forgot. But the
thing is, even with a brand new perfect made yesterday by Volkswagen “O”ring, it will still probably leak without Locktite. Not drip but a constant supply of
goo being deposited right on the clutch disc.
57. Pushrod tube seals. There’s 16. Use German silicone. Don’t use the rather stiff, short-lived hardish rubber Brazilian ones. They get hard loose their elasticity
pretty quick and then leak.
56. See 57.
55. See 57.
54. See 57.
54. See 57.
52. See 57.
51. See 57.
50. See 57.
49. See 57.
48. See 57.
47. See 57.
46. See 57.
45. See 57.
44. See 57.
43. See 57.
42. See 57.
41. Pushrods tubes – sometimes a pushrod will wear a hole in the tube. Sometimes they leak at the bellows and sometimes brand new ones
leak at the bellows. And they all have the potential to leak at the visible seam that runs from one end of the tube to the other. There’s 8 tubes
so there’s 8 potential leaks. When you install them, the seam goes up.
40. See 41.
39. See 41.
38. See 41.
37. See 41.
36. See 41.
35. See 41.
34. See 41.
33. Between the cylinder and the cylinder head. This isn’t really oil, it’s what I call combustion by-products.
32. See 33.
31. See 33
30. See 33.
29. Between the cylinders and the case. There’s four potential leaks here. Common due to not enough/ineffective sealant.
28. See 29.
27. See 29.
26. See 29.
25. The six big nuts that hold the case halves together. Use sealant. They like to come loose too. Use sealant between the threads and
the nuts and washers and the case.
24. See 25.
23. See 25.
22. See 25.
21. See 25.
20. See 25.
19. The six 12mm studs that hold the case together. Each one can leak between the stud and the case and between the washer and the case of between
threads on the stud and the nut. An O ring is situated on each stud between the case halves before assembly. But that’s not enough. You need sealant under
the washer and between the threads on each one. Use 3M Weatherstip adhesive on both. A drop of red Loctite is a good thing to. Put the glue on on the case
under the washer and some on the threads. Then start the nut one turn and put on drop of red Loctite bridging the threads of the nut and the stud. The nuts will
stay tight and you’ll never have a leak here. Leaks here can be pretty messy. Sometimes one of these nuts can actually fall off the motor and you get a real big leak
like that. Since there’s 6 studs, that’s 6 potential leaks so …
18. See 19.
17 See 19
16 See 19
15 See 19
14. See 19.

13. The long 8mm studs that hold the case together (and nearly every single stud or bolt on a transaxle too especially … everywhere, including the ones that secure the bell housing on bay window transmissions). Tighten these whenever you pull the motor. They leak between the case itself and the stud or between the the nuts’ threads and the
studs’ threads. Particularly the ones that cinch the cam plug. You’ll also need them at the two long studs that cinch number 4 main bearing and the other long stud below
these. These studs take gaskets.
They come in a gasket set – they’re just small round paper gaskets with an 8mm hole in the middle. There’s only four in a gasket set but you need at least five (plus 4 for the oil pump). You can make extras from an inner oil pump gaskets just by tearing off corners
as needed. I like to use them on the oil pump cover studs too.
12. See 13.
11. See 13.
10. See 13.
9. See 13.
8. Type III’s can leak where the oil filler tube bolts to the case. A type I can leak at the block-off plate there, if so equipped.
7. Generator pedestal. Sometimes they crack.
6. Generator pedestal base gaskets.
5. Between the oil filler and the generator pedestal. Make sure the nut’s tight. Use a single port copper intake gasket. Originally they come with a
paper gasket but it’s not in the gasket set and the single port intake gasket works great. A used one’s perfect. And forget the official tool meant
for tightening the special nut – use what’s called an “inside pipe wrench”. Available at a hardware store near you. The real tool is pretty much
useless unless the nut’s already loose but you’ll never get it tight enough with the official tool and you’ll never get a real tight one off without
an inside pipe wrench.
4.. Cam plug – be liberal with the sealant.
3 On some type III’s, there’s a metal tube leading from the bottom of the oil filler up to a tube at the breather box. Only use the correct diameter
German braided hose to join lower pipe to the upper. Using generic hose from Auto Zone, for instance, will eventually lead to a leakage
since it’s guaranteed to swell and just be funky overall. The outside diameter may be an issue since there’s little room here Hose clamps are not the answer either. Use nice German hose and no clamps. If you can’t find this hose, go to
a Porsche shop – they’ll probably have a roll of it in stock. Bring the parts so they can measure so you get the right hose – should fit real snug w/o clamps.
2. How about the split in the case? They really don’t seem to leak there much. Just tighten every single bolt on the engine that you can possibly
reach with a wrench or a socket or both, including and especially, the lower cylinder head studs (the ones under the rockers; tight by feel sans torque wrench)
every ten thousand miles or so. Don’t forget the two 13 mm nuts that cinch the cam plug and the ones behind the crank pulley that cinch the number 4 main bearing
together. Tightening all the engine bolts is really the most important maintenance you can do. And when you do it, you get
an opportunity to adjust the valves after you tighten the lower head studs (upper and remember, the upper head studs rarely come loose but you can pull the motor and check if you want to – recommended if the bottom ones are real loose or you just want to check). If you do all that regularly, you’ll get the opportunity to do it a whole bunch more times in the future
providing you have an engine worthy of such care to begin with. And remember to always crank the engine for an instant or turn it around by hand a couple times
any time you take off the rockers to settle the them in before you adjust valves. Why do this every ten thousand miles or so? Because that’s what air-cooled Volkswagen engines do – they literally fall apart.

1. And now, here’s the number one reason that Volkswagen engines leak: LACK OF CARE AND THINKING DURING ASSEMBLY. Wow – come to think of it, that’s the only reason they leak.

Type IV

Pretty much the same but there’s one thing. If you look in a repair manual for a type I, it says if you’re putting together an engine for an auto stick
or automatic trans type III, put the cam plug in concave side out as opposed to concave side in for manual transmission vehicles so the drive plate
won’t hit the plug. I’ve seen this plug installed concave side out on a type IV engine for a bus with an automatic trans. The plug had a hole in it. The
hole was formed by the end of the cam wearing the hole into the plug. On a type I engine, there’s a bit of room between the plug and put tthe end of the
cam – this just couldn’t happen. But on a type IV engine, the end of the cam is pretty close to the plug and with wear and a bit of excessive camshaft
end play, it’s a given that your odds of a leak go up drastically due to this potential for wear so don’t put the plug in a type IV engine with the concave
side out. The book doesn’t tell you to do it so don’t do it even if seems like it makes sense, as it must’ve to whoever built the type IV motor I mentioned.
Apparently, the drive plate has no potential to hit it as on a type I or type III application.

Also, type IV’s can leak every place the type I can leak including all long 8mm case studs although there’s no gaskets in the gasket sets for them. Make some
out of type I oil pump gasket corners – using the inner gasket, not the thin outer one. And don’t count on the copper sealing ring for the bolt that
holds up the oil pickup tube being enough to prevent leakage – use sealant there too. And never tighten or loosen this bolt unless the sump plate
is removed first or you may break the case. And make sure you’re using the absolute correct length bolt. Too short and it strips. Too long and it
hits the bottom of the hole and it’s never gonna be tight even if you don’t manage to mangle the threads. The right length is as long as possible
without bottoming in the hole. When disassembling a type IV engine, always loosen this bolt after you remove the sump plate and when assembling the engine,
at least start this bolt before you tighten any others and tighten it after you tighten the six through-bolts but before you tighten any other case bolts. Put the
sump plate on last. Again, use sealant on this bolt. You can even drop a little into the hole before you even start the bolt. This bolt goes through the case at the
seam and it’s subject to at least a little oil presure due to it being so close to the cam bearings. It’s got a real high potential for leakage with little or no sealant. Again
the copper ring just isn’t enough.

Of course, all the the through bolts should get sealant as a type I at the nut end and the bolt head end. You do not need new sealing nuts. If you have them,
realize the sealing ring faces away from the case. The preceding also applies to bug case nuts with sealing rings in the nuts. Regardless of what the book says,
always torque the 12mm bug case nuts to at least 25 foot pounds. If you torque them to 18 or whatever it is the book says for ’67 cases, for instance, they’ll come loose real
fast. And then … they leak. And … remember what I said about air cooled engines falling apart. Why start the process by barely tightening the thing together when you assemble it? Volkswagen used the sealing ring threads starting in about 1967 in an attempt to prevent leakage. Torque was reduced from 25 to 18 ftlbs. Later they realized that wasn’t such a good idea since then the nuts came loose pretty often so then they went back to the 25 ftlb torque with the sealing ring away from the case – type IV’s are the same. This was supposed to keep the oil from traveling out through the threads. But all you need is good sealant on the threads and under the washer.

Behind the flywheel on the driver’s side half of the engine case, there are two large (about 1/2″ diameter) oil galley plugs. Unlike type I cases,
it’s not unusual for either one of these plugs to leak. There’s two more at the other end of the driver’s side case half near the oil filter mounting
bracket. They like to leak too. All four of these plugs should be replaced with threaded plugs. If you don’t put threaded plugs in and they leak after assembly, you’re gonna be real busy fixing them.
You can fix the ones near the oil filter bracket by hassling the fan housing off – no easy task but easier on a Vanagon than a bus. If the ones near the flywheel leak, you only get to pull the motor.
Again, this is a pretty common problem with the type IV case so best thing is do it when it’s easiest – during an overhaul or when you replace the clutch. If they’re there already, pull them out
if they’re not so tight that it seems possible and then seal them up with Locktite and put them back in nice and tight. If you do try to loosen them and feel uneasy about them coming out nice, try some applying heat to the case to expand the hole and it may come out then. But … whenever you attempt to loosen any bolt and fail, always then try to tighten it a bit more. If you don’t, it’s far from out of the question for it to come loose or even fall out the next day or some time down the road unexpectedly. This especially applies to rear axle nuts and wheels.

To fix these plugs, you need to drill a hole in the existing plugs. They’re thin so be careful. You can pry them out with … something. I use a tiny pry bar gingerly hammered into the drilled hole. Heat can help make it easier = don’t break the case. Use a 3/8 pipe thread tap. Plug diameters vary so trial fit as you tap. You may even have to grind some of the taper off the tap to get the tapped diameter to match the unique diamter of the plug you actually have. You’ll only get about 2-3 complete turns of the threaded plug when you install it because there isn’t much depth here but that’s enough. Use red Loctite on sterile (zero oil) threads when you install. You can use brass or steel plugs. Brass plugs need a crescent wrench to install (you may have to grind it down for clearance) but steel ones can be either allen or a square engagement and mount flush. A correctly tapped hole ;is slightly tapered to the resistance increases as you screw the plug into the hole. Do it right and very carefully and it’ll never come lose.

For the big rubber O ring for the ‘inspection plate’ on the bottom of the motor – use silicone glue or it’s very possible/likely to leak. Even with a new seal and perfect installation. it’s very possible you’ll get a leak there without silicone. Snug up the two bolts
then let the silicone cure for an hour or two before fully tightening. Make sure the area is totally dry and free of oil before applying glue. If the engine
is in the vehicle, lift the passenger side of the vehicle as high as you can so the oil in the engine flows away from the opening to keep the oil from
continuously dripping – even if it’s been drained. Even with lifting one side, you may have to drain some oil out. This works. Realize glue will not seal oily surfaces –
they must be absolutely dry.

Use sealant (Gaskacinch) and let is set for awhile before you finally tighten the oil filter mounting bracket. If it leaks you’ve got alot of work ahead of you to clean up
that mess. The oil cooler has to be removed just to tighten the upper nut for the bracket. And the cooler is buried. I usually make this gasket from a magazine cover.
Magazine covers come in various thicknesses so don’t go too thick or you risk breaking the bracket upon tightening. From my experience, I think the original gasket
is too thin. Try to pick something (magazine cover) that’s just a little bit thicker than the orig and you’ll be fine.Just glue the paper to the bracket with sealant, let it dry, trip the edges (lightly tap edge with hammer and it’ll but the excess). Poke the holes with a small phillips screwdriver then clean up the edges with a round file. Same goes for the outside edges.

If any of this makes sense to you, why would anyone want to add an external oil cooler/filter to a vehicle? Heat? It seems more like an external oil cooler
is better at creating more potential leak points than increasing engine life. All those brass fittings and rubber hoses, hose clamps, barbed (really tacky) fittings, even
braided steel lines – ually pretty quickly, albeit the leak is only detectable in the beginning due to the road dust accumulating on it.VW knew how
hot their engines we’re gonna get. Maybe for racing but not for a daily driver. One thing that makes me gag is when I see a real nice bus with big giant holes drilled in the side of the body next to the engine for external oil cooler hoses to be routed
through. And sometimes a whole bunch of little holes often get drilled to install an split bus aftermarket fiberglass air scoop to help the cooler be even cooler.
These air scoops are guaranteed to fly right off the bus someday – they break. This leaves a lotta holes and scoops only come in pairs. I guess if you’re the guy who put them on in the first place, it’s very likely you’ve got the other one still laying around? And an external cooler makes the oil
take a long time to warm up. Bad for engine life, especially if you usually don’t drive for more than a half hour or so. Oil takes a long time to warm up and the faster an engine warms up, the longer it lasts. The thing is, the weak spot in a VW engine is the heads – the valves. A cooler mounted before the fan only cools oil. The heads are now being cooled by air preheated by the cooler. And don’t mount it under the bus. Unsafe and you’ll need even longer hoses.

Use only red silicone flywheel seals (NOS seals are white). Never use Viton seals. They always leak. Sometimes alot. Viton seals can be all brown or red and black. There are also black seals for type IV engines. This is the worst one of all. USE RED SILICONE ONLY. Use red Locktite as described earlier for the O ring mating surfaces and in each flywheel bolt hole and on each bolt. This keeps oil from making its’ way past the O ring and onto the clutch via the bolt holes in the flywheel.

Do you think VW would sell brand new cars if they thought – by design and thus inherently – the oil temps were to high? There’s nothing wrong with the stock cooler and … no hoses. If you insist on doing this, route hoses so they’re far from exhaust heat. This much heat makes soft rubber hoses get crispy pretty quick. You don’t want to lose a motor when your effort to keep it cool kills the engine when a hose “overheats” and spews all your oil out on the pavement at 60 miles an hour.

Type IV engines lasted a real long time. Rods seldom flew off the crank and when they did, the mains usually looked pretty good and the engine was real old with a lot of miles. With the exception of the occassionally somewhat pitted center split main. With too-hot oil, that would have never been case. VW’s don’t run hot – the just run what they’re supposed to run at.

As far as gauges go – pretend it’s 1972. You’ve got a guage in your nearly new bus. It’s reached the temp your mechanic told you was overheating so you pull over to let it cool. Meanwhile, 22 VW buses travel right by you on the freeway while your sitting there. They all make it to their destination. Of course, they don’t have a gauge. Gauges? No reason to own one unless you like to install parts on your VW that don’t fit anywhere and VW, who made new cars and did all they could to last through warranty didn’t deem necessary. Gauges? Just for show and real handy if you want to find a reason to chop a big hole in the dash so they fit.

Main bearings last a long time. The thing that damages them is too high an RPM for long periods of time like on a trip on the interstate. And the one thing that oil can’t prevent is wear on the main bearing bores.
.Especially the split center main bearing bore. All the others bearings are full circle bearings. The full circle bearings don’t move much but they do move. But the split bearing moves a lot more than the others – it’s made out of two pieces. It can’t help but move. From the moment you start a new engine. And as it’s moving, it’s always pounding away at the case. And regarding hardness, the case is like butter compared to the bearing. So over time, the crank beats the bearing into the case, the bore in the case gets bigger, making the bearing pound even harder. All the while, the cranks banging away at the other side of the bearing. Regardless of oil temps, once the bore gets pretty worn, oil has little effect on this hammering. All oil can do is provide slipperyness to enable the crank to spin without galling the soft crank side of the bearing. This is what really does in the center main, not oil temps. Basically, the bearing starts out as a relatively stationary part, and over time, due to crankcase wear, itbecomes a moving part and the crank side starts to wear.

Anyway, oil temp has nothing to
do with crankcase bore wear – it’s higher revs that wear crankcase bores. Imagine trying to hold – with your bare hands – a spinning crank with all components attached to it and
pushing a car up a hill 50 miles an hour. Yeah, you couldn’t do it. But that’s what the case is doing. And it’s made out of what’s probably the softest (maybe the wrist pin bushings are softer? or the pistons?) material in the engine.
It’s the radial movement of the crank at high rpm that causes the center main (and much less so, but significantly, the other main bearing bearing bores) to literally pound away at the center bore like a hammer. Cooler oil won’t help that. The only solution – slow down.