Major Oil Leak

I am having some problems with my 98 jetta tdi AHU, i cleaned the intake manifold last weekend and now this week i smelt burning oil, i looked under the hood and where the egr valve is on the INtake manifold there is a hold on the one side (looks factory) and oil seems to be coming out of there, and going down onto the intake/block than onto the egr cooler hoses, i dont know if i should clog that hole and see what happens or what? any help would be awesome thanks, i will try and get some pics of it.

Hey Shut,

That hole is a vent hole for the workings of the egr valve. It has an o-ring type seal I believe, and when that goes the pressure of the boost squeezes blowby out of there. The oil that is coming out is the oil that is in the air that is going into your cylinders. One way to stop the oil from coming out (you won't be able to stop the pressurized air from leaking out until you fix the o-ring, which I think may require a new IM) is to put a ccv filter on, something like the Provent or one of the home-brewed ones...this will reduce the oil that comes out. The other way is to disable the egr valve and then plug the venthole with something. I have this same problem but I haven't plugged it yet. I am going to try using a high-pressure rtv sealant and see if it will hold. I've noticed if I drive easily and keep the boost to a minimum the oil doesn't come out too much, but get on it awhile and it will start spraying onto the valve cover, etc.

The problem with an integrated egr valve is we may have to get another IM to stop that problem...I haven't really heard a solution that will repair that on the car. Good luck with this...I think my leak is getting worse.

Just for future reference, this problem may have been caused in two ways when you cleaned the IM...1) if you dipped the IM completely into some solution strong enough to clean off the oil and soot, it could also have eaten that o ring...2), it may have been leaking for awhile but the buildup of the crud on the inside of the egr may have blocked the leak...not sure about that last one.

I believe the hole in the egr valve you are talking about is the vent hole for the underside of the diaphragm in the egr valve. When the vacuum pulls up on the top side of the diaphragm to open the egr valve, the bottom side of the diaphragm needs to be vented to atmosphere to allow the diaphragm to move.

The egr diaphragm is connected to a rod that runs through a bushing into the intake manifold and then connects to the actual valve that allows exhaust gasses from the egr cooler into the intake manifold. The reason you see oil coming out of the egr vent hole is that your bushing is worn out and allowing pressurized oily air to make its way between the shaft and bushing and out the vent hole. Your post says "major" oil leak. If it is more than just a dribble, I would wonder why you have so much oil in your intake?

I have a 1998 jetta TDI. When I cleaned out my intake manifold I noticed the large amount of slop between the shaft and bushing was not only causing the oily mess from the vent hole, but also the egr valve would not seat and close properly because the valve and its seat were no longer concentric. Because the egr valve is an integral part of the intake manifold on our cars, the only way to fix the problem and still have egr is to replace the entire intake manifold with new. I suspect this is expensive, but I never priced out a new manifold.

My solution was to make a blanking plate for the connection from the egr cooler to the egr valve, and then also take the egr diaphragm, shaft, and valve out, then drill and tap the bushing and install a bolt in the bushing with red loctite. (The manifold needs to be off the car to do all this so you can clean up the metal shavings). I live in PA and diesels are exempt from emission inspection. I now have a CEL on all the time (egr system - control difference).

You don't want to just plug the vent hole to stop the oil leak. Pressure from the (turbocharged) intake manifold will build up on the underside of the egr diaphragm and open the egr valve when it's not supposed to.

Greg Shortridge

The o Ring inside the Intake is the problem. either worn out or the cleaning solution destroyed it. theres no way to disassemble the egr and replace that or just start looking for a intake manifold?

A new integrated IM/EGR is about $400...

I guess they figured this out, and that's why the A4s have a seperate EGR. Unfortunately it seems like this is something us B4/A3 drivers will have to live with.

yeah, lesson learned, can i do any major damage buy not replacing my intake manifold and just run it with the leak? other than my oil useage will go up

Bunch of us run with the oil oozing out. I am not about to pay big bucks for a new intake.

I have the same problem on my 1995 passat wagon tdi, leaking oil (small drip- enough to make my driveway ugly)out the vent hole on the egr. Anybody else have a fix other than buying a new IM? I'm glad I am not the only one with this problem.

i was thinking about running a line with somesort of fitting from the hole to a resivoir just to see how much it is leaking and keep it from making my car a mess

I was thinking the same thing, I was going to put a metal dish ie bottom of a aluminum can under the drip but the line sounds better. Mine seems to leak about.... ah 1-2 cc per hr.

I was thinking about that myself, mine does not leak yet, but I'm sure it will some day. I am going to tap the EGR vent hole (with the manifold off) for a small brass male hose fitting, and run the hose either into the CCV, or just attach a small in-line canister type fuel filter with the outlet blocked off to collect the excess oil. Then just take the filter off periodically and drain it/clean it out.

Good idea d-orgy, will try that myself, heading out to the local can-tire for fittings. My egr comes off the manifold by removing 2 hex bolts on the flex pipe and 2 hexbolts on the cooler side. Shouldn't be to hard. I might have a look inside the mechanism ie rod/plunger to see if it is just gunk built up and not letting it seat correctly or if it is the o-ring that is shot. Anyways I will try this out tommorow night. Cheers, thanks for the good ideas.

So I tapped the egr vent hole with a drilled out grease fitting and attaced some tubing to it. I have it draining into a clear 500ml bottle below. It is working for the last 2 days approx 300km and approx 5-6 cc collected. no more drips on the driveway. Seems to work for now. 29cents and free plastic tube + 1 hr of my time vs $400+ for a replacement em/egr valve. I guess my other option would be to run a provent. I am shopping for it (provent) now just to see price and setup.If anybody has dealers(provent) price for the Ottawa , Ontario area please let me know. Cheers

Wasted gate.......

Is there any way this would let the pressured air out or leak and cause the same effect as a leak elsewhere in the turbo system, causing poor performance and heavy smoke? thanks

Has anyone had a similar problem on A4s?

FirstOrbit84 said:

Has anyone had a similar problem on A4s?

Click to expand...

Yup, but you can replace the EGR as a separate item. Just bolts onto the intake.

I have this same issue, its not that bad... But im planning on cleaning my intake soon, and chances are it will get worse! Im thinking about maybe tapping the weep hole, and putting a fitting on it with a hose.. Then tapping a hole in the valve cover and dumping there.... Any thoughts ?

I'd probably dump it in the hose going from the CCV vent to air intake pipe.

So im not thinking to far out of the box....