Former VWDieselParts.com Forum

Searched high and low for your famed posting titled "Oil Out the Dipstick", but found nothing. Can you please post a link?

On the drive back from a long weekend of camping in our 83 Westy with 1.6NA diesel, I noticed the rather sudden appearance of oil flecks covering the rear tailgate and window. One minute, nothing; the next, quite a mess. Popping the engine lid, I saw oil flung everywhere, especially around the belt and pulley area.

There was no loss of power, no overheating, no mingling of coolant and oil, and no evidence of the burning of either. Taking it easy and keeping an eye on the oil level, we limped home at low highway speeds.

After cleaning the engine compartment and firing it up again, I've traced the leak to the dipstick tube, suggesting excessive crankcase pressure. Not a lot, just a slow and steady drip that falls down onto the V-belts and gets flung everywhere. I also found the air filter was all sooted up and partially collapsed onto one of the intake runners inside the airbox. All the rubber bits of the filter were intact but I might to be missing a dime-sized piece of the paper element, presumably sucked into the engine?

I'm getting some blowby from the valve-cover vent hose and from the oil-filler cap, though I don't know how much is acceptable in a diesel, nor how much it has increased over the years. I once owned a very worn-out Datsun that would not allow oil to be added when the engine was running; when you poured oil into the valve cover, the high blowby just blew it all back in your face. The blowby from my VW diesel (106k pampered miles) isn't anywhere near that bad. Replacing the air filter seemed to reduce the drip somewhat but it's still there.

Obviously, all this points to worn rings or valve guides, but what strikes me is how suddenly the leak appeared, suggesting perhaps a BROKEN ring instead (or perhaps a bit of filter paper stuck somewhere)? I changed the oil and filter, so I suppose the next step is to do compression and leakdown tests to get some idea of the general condition, and maybe pinpoint the offending cylinder.

I generally don't like additives and other magic-in-a-bottle, but a respected VW mechanic specializing in the air-cooled engines likes to occasionally run a half-quart of Marvel Mystery Oil in the fuel tank and another in the crankcase for 300 miles, then dump it. He feels this burns off accumulated carbon on the piston heads, valves, and rings, and loosens up other crud in the engine. Instead of the expected thinned-down oil, he drains all manner of tarry black crud out, and claims the internals are visibly cleaner on an engine that has had this treatment a few times.

Any advice to offer?

I remember that thread as well, and also could not find it- My golf had a guyser of oil from the dipstick before i re-ringed it. There are 4 ways to fix this issue that you may want to try:
1. Re-Ring the engine
OR
2. Install a oil splash guard on the cam, then drill out the PCV restrictors in the manifold to allow more air to escape- this worked great for me, and the oil splash guard stoped any issues with run away.
OR
3. remove the dipstick and use a pencil eracor to "cap off" the oil this got me to work for months before i saved the money for a re-ring
OR
4. remove the PCV tube, cap it off with a bolt and a hose clamp- then buy 4' of heater house and put that on the valve cover and route it strait down to allow the PCV air to simply dump, not the best fix but since every ford dodge and big rig does this, im sure our tiny VW's wont hurt anything

Joe

Well I joined Oct 2002 and my first post isn't until Jan '03 so I must have some missing posts... that's about the time I posted it too.
The problem was caused by too much pressure inside the block and the solution was to drill out the restrictors in the intake.
The A2 Jetta that was having the problem, had the A2 intake.
The vent comes off the valve cover and splits into 2 hoses, both going to ports on the intake. Inside the ports are restrictors. Drilling out the restrictors allowed more gasses to flow from the vent and pressure was relieved.
The car never had a runaway and lived a few more years after that.

Thanks, JRM and Fatmobile.

I had already installed the suggested oil splash guard a few years ago, and although I'm getting SOME oil droplets out the valve cover vent, it's mostly vapor/blowby. I have NO signs of runaway.

How large should the restrictor holes be drilled-out? Are they cast metal like the intake manifold or some sort of plastic insert? If they can be drilled with the intake installed in the vehicle, how do you prevent the drill shavings from falling down into the intake runners and getting sucked into the engine?

And what do you guys think about how SUDDENLY the oil leak and backpressure appeared? It seems like something suddenly changed, instead of the expected slowly worn out engine.

Thanks for all the advice!

You bring good points! The restrictors are made of a light weight metal, almost like a washer that lives a few inches down there, you can see them pretty easily with a flashlight, i have forgotten what size i drilled them, i think only 2 sizes larger bit than what fit threw the org hole.
As for shaveings, use a shop vac to suck em out as you drill, Mine was off the car but one "should" be able to stick a shop vac threw the air intake.
As for the sudden increase, yea that is strange- cracked head?
Id check for pressure or oil in your coolant tank... keep us posted
Joe

The valve cover has metal mesh under the crank vent. The mesh helps to seperate oil mist. It can get clogged by buildup and if it does will cause an immediate increase in crank pressure like you describe.

Andrew

no metal mesh under mine, has a baffle but thats it- wonder if someone pulled it out?

I think they were drilled out to 5/16".
Yours isn't an A2 Jetta so look at your intake and see if it has the two ports for the vent to go to.
I drilled mine out with the intake on the car and a shop vac hooked up.... it worked for me.

Thanks for the tips.

I've changed the oil and filter, am not getting any mingling or consumption of coolant and oil, so everything else seems normal.

If the valve cover vent screen got plugged up, wouldn't the blockage actually DECREASE pressure exiting that vent line (while, of course, INCREASING internal block pressure)? I seem to be getting the same pressure at the vent line as the oil filler cap. In any case, I'll pull the valve cover and have a look under there.

I'm going to try the VW mechanic's MMO procedure in the faint hope that this is simply a stuck or carboned ring, then probably drill out the PCV restrictors, before taking it in for compression and leakdown tests.

I will post back what comes of it all.

I'd like to get a few more miles out of her while I source a rebuilt 1.9NA ...

I did searchs on "intake restricters" plus "oil out the dipstick" and found out quite a bit on this cuz my vdub is doing it too. The answer always comes back to worn out engine, need a rebuild. I'm getting a small dribble of oil coming out the dipstick tube at about 1500 or 2000 RPMs and up. Nothing at idle. I can't say that I notice the engine smoking like in blowby. Fatmobile has suggested in many posts that drilling out the restricters located in the intake will allow another year or two of service from the engine. But my engine has compression readings of 460, 490, 380 & 460. Yup, one cylinder is a little lower than what Jack says is the threshold for a rebuild. My oil pressure is 80psi at startup and 35-40 when warmed up. So I'm wondering if there isn't something else wrong with mine that might cause this crankcase pressure instead of a worn out engine. Just one cylinder that's just a little low doesn't seam like enough to cause the excessive crankcase pressure. The engine is from a '86 Golf and I installed in the '89 Jetta that used to be a gasser. It's not on the road yet, 'til I work this out; and spongy brakes.

i drilled out the restricters located in the intake to 1/2 inch holes during my last rebuild to curb this in the future, as my golf read 280's on all 4 cylinders and was tough to start warm. you can always run a piece of heater hose from the valve cover strait down becide the tranny, some dont like the pollution but all larger rigs do this.

I've heard of the screen mesh in the valve cover blocking the crankcase vent, That would back up some pressure.
Pull the valve cover hose and see how the gasses are venting from it.
Compare it to how they vent from the valve cover cap.
See how badly the oil comes out the dipstick with the hose disconnected.... see if it helps.

Removed Valve Cover cap. The pressure under the valve cover is obvious; and it is relieved with the cap off. Does the same, equally, when I remove the hose from the valve cover. The air puffs out pretty strong. Looks a hint of smoky too. Left the hose off and revved the engine up and held it at (guessing) 2000 or 3000 RPMs for a half a minute or so. Normally this would be enough to see oil dribble out the top of the dipstick tube. None comes out.

Another way to reduce block pressure is to vent the block to the intake.
viewtopic.php?f=8&t=12897

Early 1.5 blocks had a recall where they ran a hose from the block to the intake.
Because the pathways between the head and block were too small.
Larger pathways for oil to return were cast into the 1.6 engines.
So they didn't use a hose to a block vent.
But they brought the idea back up in the 1.9 AAZ blocks.