AAZ Vanagon losing oil

[air-cooled or diesel]

So  I assume it is definitely bad rings? Could it just be the oil rings that are bad. Hence there no lack of performance, or hard starting?

i never heard of a ring of the set on a piston wearing alone, abnormally. the oil ring essentially rides on the cyl wall, not really doing much more, the 2 upper rings do all the work, and have all the pressure on them. one thing to consider is how this happened, as iirc you recently rebuilt motor, bad air filter? not changing air filter, air leak post air filter? open cc vent w/o a filter? not changing oil properly?

[RockOcean]

Ok, what would be a cause for oil usage from the crank vent?

I was thinking maybe when I gapped the rings 4 years (90k) ago when I rebuilt the motor that I gapped the oil ring slightly wrong which is why I have always lost some amount of oil that has gotten progressively worse. With a 500psi compression test done six months after the rebuild, I assume I gapped the other rings just right.  I guess the only way to know for sure what may be the cause is what I will find once the head comes off, and I can see in there. Anything I should be looking for, or measuring once I do that?

[air-cooled or diesel]

Ok, what would be a cause for oil usage from the crank vent?

one thing to check, is your power brakes working correct? a vacuum leak from vac sys/pump can push oil thru ccvent. since you seem to have oil pressure i assume the vac pump is installed correctly, easy enough to get right, but vac line to booster or integrity of booster its self. a leak can push air pressure into cc and oil can easily get pushed out; although the dipstick is a common place for this to happen. i suppose any ccvent/opening can be a result of this.

[RockOcean]

Ahhh yes when the brake pedal is depressed when it's cold the booster behind the instrument cluster makes a hissing noise on the first depress. The hiss goes away if you depress it again right after that. That being said tho the brakes are functioning fine. The other night I had to slam on the brakes when two moose decided to cross right in front of me while doing 50mph. I was surprised how quickly the van stopped.

[RockOcean]

Since driving 500 miles with the CC hose venting into a bottle I am still losing a half quart every 100 to 200 miles. But there is no oil in the catch bottle. This leads me to believe that the oil is draining from the catch can back into engine. Which is good and bad, since I shouldn't have that much oil from blow by. But at least I have a set up so that it goes back in the engine. But now i'm back to square one wondering where the oil is going? It is interesting to note that the 2 times I have changed the oil on this trip I have been able to drive 500 miles before having to add a half quart? I am going to see what lowering the boost does, currently it is set at 9psi max which I rarely ever reach cause I drive it so easy. I think lowering the boost may keep the crankcase pressure down a little bit and hopefully help out.

[air-cooled or diesel]

a compression test will tell you much more than(,,)

1 thing i can think of, block off(temporarily) the catch can return, before the catch can fills up and overflows, check if here is where the oil is going. make sure block off doesnt botch something, and (also)can doesnt suddenly overflow and starts gushing,out. make sure catchcan  breathes.                                                                          ^^-like ruin plumbing, endup in the block, etc.

[theman53]

what turbo do you have and how many miles are on it? Also 9psi shouldn't be a problem for any turbo that is in range on these engines.

[RockOcean]

I deleted the catch can and it puked a good amount of oil into a test bottle. This oil must now be going into the cc and draining back into the motor as I have driven over 800 miles and there is no oil in the test bottle that usually would go into the intake.

It's a KKK K03 with about 90k on it. Since limiting the boost to only 5psi I have not been losing as much oil. I also have switched back to 15w-40 "dino" Rotella oil since it is much cheaper. I'm in Homer, Ak heading to Haines to take the Ferry to Bellingham, WA and then down to Northern California. Hopefully I can make it those 1700 miles on the 8 quarts I have:~ )

[theman53]

Bet you about anything it is the K03. Friend of mine with an ahu has been through 3 of them. All using tons of oil as the center section goes bad. He was running about 15psi on all of them and they don't make it long on that.

[RockOcean]

What should I be looking for to pin point that as the problem?

[theman53]

the worst one of his the bearing would rotate in the center section and almost plug it off. Yours probably isn't that bad. I would get a known good K03 and replace that one of yours and see. Another thing his was doing when it was really bad was the downpipe had some oil residue on the inside of it.

[RabbitJockey]

yeah k03 is a crazy small turbo, and im sure its working hard in a vanagon.  but just for my own pride... who suggested scrutinizing the turbo first?  it was me

[RockOcean]

Well it seems that turning down the boost has helped the oil consumption a good amount. I have only been losing a half quart every 250 miles since making that adjustment. Also putting in the dino Rotella may be helping too. We are bout to get on a ferry back to the lower 48 leaving us with just 700 miles to drive to spot where I can finally fix up the engine right. While the blow by may not be the biggest cause for the loss of oil it is still something that needs to be fixed. I might start by putting on a new turbo as I have sourced a Borg Warner for $500. The turbo actually has about 120,000 miles on it, I forgot I ran it for about 30k before I rebuilt my engine. On top of that the turbo was rebuilt at that time and not new. I look forward to finally fixing/rebuilding this engine correctly this time, and will post photos along the way. Thank you everyone for all your help!

[RockOcean]

Hello again, since my last post I drove my van the 700 mile to Northern California with the same problem. Losing half quart of oil every 200 miles with no sign of any smoke, and no leaks any where. I then took some time off the road for awhile which is why I did not post up until now. I was planning on driving from L.A to Maine this week with plans to pick up an AHU engine (70k) with wiring harness for only $1200 in Wisconsin. But 250 miles into the trip I had to add 2 and a half quarts of oil! So I turned around with plans to rebuild the engine.

The first thing I noticed when taking the injectors out to do a compression test were that #1 and 2 injectors had burn marks on them that 3, and 4 did not have.

Injectors by RockOcean.com, on Flickr

My compression numbers are: #1 (395) #2 (395) #3 (395) #4 (300)

The AAZ specs (Bentley pg 15a-2) are:

New:  493 psi minimum
Wear limit: 377 psi minimum
Max difference between cylinders: 73 psi

I am planning for a full rebuild once again. My brother sells VW parts so this is very easy for me to just order everything I may possibly need. And if I don't need it I can return it.

As for now I plan on taking in the head, and the block to a machine shop on Monday to have them tested.

Any recommendations for 80.5mm over sized pistons and rings?

Last time I rebuilt the engine, I did not get the block decked to provide optimal piston protrusion for a 2 notch gasket so I will be doing that this time.

Any other suggestions would be greatly appreciated thank you so much!

Garage by RockOcean.com, on Flickr

[RockOcean]

Upon inspecting the intake piping it looks as though there is a lot of dust in there. Somebody had mentioned that I may have "dusted" my engine. So if this is the case what all could have been effected by this?

Dusted by RockOcean.com, on Flickr