Oil in Coolant

[trav1856]

This is my first diesel, I just bought it Wednesday, and haven't really driven it (nor do I plan to after I discovered oil in the coolant).

(81 Rabbit Diesel 155kmi)

So my question to you guys is this. My plan:

Drain coolant and flush
Drain oil and flush

Check oil for coolant/water when I do.

If there's coolant in the oil also, I'm thinking headgasket, or rebuild.

Thoughts?

[maxfax]

   Oil in the coolant on these is classic HG failure.. From my experience it's actually less common to have coolant in the oil unless it's also getting coolant in the cylinder....  IT is possible, however, that if the car has had a HG replaced it could be redisual from the past failure.. Has the car recently had a head gasket?? 

Since your car is an '81 it will have the 11mm head bolts, unless the engine has been swapped at some point.. The thing about 11mm head bolts, they were notorious for causing cracked blocks, especially after a HG replacement..  Fortunately a set of head studs will help in preventing that..

[coke]

The switch to 12mm headbolts occurred in 81. Some 81 have 11, some have 12. You'll have to double check.

[trav1856]

Ah, so this is common.

As far as HG failure, that I don't know. I just bought it 3 days ago. Trailered it home. Drove it on and off the trailer, and about 2 miles down the road for a test run. The engine runs like a champ. Starts up slightly rough but starts right up.

Runs well, but oil light comes on after about 5-10 minutes. Not sure what that's about. Oil pressure seems to be good.

[maxfax]

The headbolt switch was officially in '81, however, many of the Westmoreland built cars still had 11mm bolts through '82..

These engines can run perfectly fine with nothing more than oil sprewing into the coolant..  But eventually the rest of the gasket will start to decay..  Not to mention oil wreaks havoc on the cooling sysem..

Have you checked the oil pressure with a gauge?? Before doing any sort of surgery I'd verify it's good.. 

Does your car happen to have 2 oil pressure sensors?  One on the head, one on the oil filter housing...

[trav1856]

it might also be prudent to note that the aircleaner was filthy with oil.

[maxfax]

it might also be prudent to note that the aircleaner was filthy with oil.

That's a different beast in itself..  Could be that the filter hasn't been changed in ages, could be excessive blowby..  In later years they added a plastic baffle under the valve cover to help prevent oil being blown into the intake.. IIRC it was about '86 when they did that, but the baffle can be bought and installed in earlier models...

[trav1856]

Gotcha, so a good idea might be to crack the air box and hold up a papertowel to the breather tube and check for oil at revs? I found the baffle listed somewhere, was pretty affordable, just didn't know where it went or what it was for, but that's good info. Thanks.

[maxfax]

Even easier, just open the oil cap and see what you have.. If there isn't a baffle in it you should be able to see the cam.. With the engine running, a little oil splashing out (with no baffle) is no big deal, what you want to take notice of is how much pressure is blowing outta there..

Even with a fairly healthy engine I've found that the filter would get nasty without the cam baffle..  And it'sindeed an easy, cheap, upgrade.. Since you'll have the valve cover off the molded rubber gasket as used on the Corrado is a nice upgrade too..  Seals so much better and is reusable which come in handy since you have to remove the VC to replace the timing belt.....

[arb]

it might also be prudent to note that the aircleaner was filthy with oil.

That's a different beast in itself..  Could be that the filter hasn't been changed in ages, could be excessive blowby..  In later years they added a plastic baffle under the valve cover to help prevent oil being blown into the intake.. IIRC it was about '86 when they did that, but the baffle can be bought and installed in earlier models...

Yeah, very common without the baffle. I'd try your process to see if there is something to fix.

[trav1856]

Something else I found: http://www.automotix.net/autorepair/volkswagen-rabbit_convertible-engine_repair_guide-2189.html

Oil in Cooling System on
VW 1.5L & 1.6L Diesel Engines

AERA members have reported instances of engine oil in the cooling system on VW 1.5L diesel engines. According to AERA sources, the problem is related to a crack in the cylinder head bolt hole located near the oil gallery feeding the cylinder head.

The oil feed gallery in the block is located on one side of the center head bolt hole and a coolant jacket is on the opposite side of the bolt hole. Pressurized engine oil is diverted through a slot in the head gasket and is feed up the side of the head bolt to the cylinder head. The oil also follows the bolt back down to the bottom of the bolt hole. Should the crack in the head bolt hole extend to the coolant jacket, oil can mix with engine coolant.

This problem is generally found on engines equipped with 11mm head bolt holes. Later design engines utilize 12mm head bolts and do not exhibit this defect. At the time of this writing no successful repair procedure is available.

The AERA Technical Committee

[maxfax]

 Driving one like that for the last few years... Indeed there is no permanent successful repair as of yet....  However head studs are a good way to help prevent it from happening.. 

Educational Reading
http://www.vwdiesel.net/forum/index.php?topic=21948.0

Just plain nuts
http://www.vwdiesel.net/forum/index.php?topic=22403.0

[trav1856]

Thanks for the good reads, Max. I particularly like the "ethnically engineered" solutions. Just goes to show what can be done.

[maxfax]

The freakiest part is, I just got done rolling another 50 miles on it..  And it'll go another 50+ tomorrow.. The darned thing starts and runs excellent.. Unfortunately I've robbed just about all the hoses from my parts cars, and I can;t bring myself to go buying new hoses for the thing..  I've ordered the rest of the parts and started to assemble my 12mm engine..

Don't be surprised though that there won't be a thread in the future about what I find when I pull the head again, and see what went wrong....

[R.O.R-2.0]

The headbolt switch was officially in '81, however, many of the Westmoreland built cars still had 11mm bolts through '82..

These engines can run perfectly fine with nothing more than oil sprewing into the coolant..  But eventually the rest of the gasket will start to decay..  Not to mention oil wreaks havoc on the cooling sysem..

Have you checked the oil pressure with a gauge?? Before doing any sort of surgery I'd verify it's good.. 

Does your car happen to have 2 oil pressure sensors?  One on the head, one on the oil filter housing...

my vanagon engine is German, and an 82 or 83, and it still has 11mm bolts, and a 17mm 6pt crank bolt.