B4 Oil Leak on Front of Engine

My 96 Passat has an oil leak on the front of the engine.

From the accumulated oil and dirt it would seem it has been going on for some time (probably long before I got the car). The area of dirt and oil was quite big, covering from around the oil filter bracket/dipstick to the left edge of the engine around what I assume is a vacuum pump. The quantity is not too bad (1qt/1500mi), but it is making a mess of things.

I cleaned up this area as best I could (brushes, simple green and water) and checked for loose bolts on the flanges/brackets (none), and am running it to try and see where the source of the oil is. (FWIW the gunk was thickest around the vacuum pump, but that may have just been airflow.) Cyl head was clean so I don't think the oil is running down from there.

Any BTDTs out there? Where do front of engine oil leaks typically come from on this model?

TIA

One area has been the CCV "weep" tube from the valve cover to the block. The plastic flange that bolts to the block gets brittle over time and cracks, causing a leak.

My oil leak came from the oil cooler where it mounts to the block. I had the gasket between the cooler and block replaced and no leak since.

It took several cleanings and steady observation to finally pinpoint the leak.

Good luck!

I concur with mleone. One word of advice learned from personal experience: Remove and inspect these parts to confirm damage and most importantly, the VW part number stamped for ID. In my case, I ordered the part from VW only to find they sourced the wrong part!

I'll throw a vote to check the CCV tube. On top of the valve cover is a "hockey puck" looking valve. Follow the tube from this valve to your block. Where this tube meets the block is a very common leak area. I replaced mine with success at 120k mi.

It is an easy job. Two bolts with decent access if you have the correct allen wrench. I got a 6mm set from Sears (2 wrenches) and the small one was just right.

I have also heard to replace the puck, as it may be open all the time letting excess oil thru.

Part (if I remember is $36 for the tube, and 26 or so for the puck) from impex.

Good luck - here is to no more oil leaks!

Kurt

Just to add my resent experieance on replacing the CCV vent tube. The two screws at the lower end of the tube were pretty difficault to remove...reason is usual...corrosion ...and partialy siezed. I used 1/4" dr. extention ...and a swivle joint ...that made the job doable...witout having to do a whole lot of dissembly of wiring harness'...ect...ect.

I just went through oil leak hell on my Passat a few months ago. My oil leaks had several sources. As already mentioned, the CCV tube weaps oil where it bolts to the block. The O-ring between the tube and the block was hard, brittle, and deformed. On the 96 Passats and early 97 Passats, the plastic CCV drain tube is one piece. Sometimes these tubes will crack from vibration. VW changed the CCV drain tube to a two piece design sometime in early-to-mid 1997 to eliminate the cracking problem. If needed you can get the new two-piece replacement CCV tube from VW or any of the better on-line wholesale parts sources. There is another O-ring where the two tube sections connect. This O-ring is the same as where the tube bolts to the block.

I also replaced the two O-rings on the vacuum pump. These O-rings were also hard, brittle, and deformed. One O-ring is under the vacuum pump lid, the other is on the vacuum pump shaft when you pull it out of the block. These two O-rings were the easiest to replace.

I saved the worst for last. The most common leak area is the O-ring between the oil cooler and and the oil cooler manifold plate. This is also the hardest to replace. You remove the oil filter, then the large nut that holds the oil cooler to the plate. If you have extremely good dexterity you can pull the oil cooler down off the plate without removing the threaded pipe. Then you just replace the large O-ring. This O-ring has two tabs that hold it in place on the top of the oil cooler. There are several nubs (for lack of a better term) on the top of the oil cooler that the tabs can hook on to. I ended up removing the threaded pipe to give myself more room. The pipe is not very tight and can be easily removed. I used a large torx bit that I pounded into the pipe and then the pipe unscrewed right out. I installed the pipe the same way after. The pipe threads and the nut that holds it on is SAE English, not metric. To remove the nut you will need a deep socket around 1" or 1 & 1/16" or something large as that. I don't remember the exact size anymore.

It is possible that the gasket is leaking between the engine block and the oil cooler manifold plate. It is very rare for this gasket to leak as it is metal, but if it does, you will have to remove everything off the block. Not a fun job at all.

If the source of the oil leak is the oil cooler O-ring, the job is easest when doing an oil change. You will still drip oil everywhere and make a nice mess.

Good luck and have fun.

Brian, 97 Passat TDI

First, thanks to all that replied, The CCV down tube would seem to be a likely culprit here. I will clean some more and look for fresh oil.

You mentioned that the hocky puck thing on the valve cover is supposed to limit air/oil flow? That's odd, just cleaned mine out and it appeared the be a baffle inside but no more,;it always allowed air to flow easily. Is there a valve in there that closes? How would one test it? (And is there supposed to be a tube going to the small spur thing on its bottom?)

TIA (again)

It is my understanding that it(the puck) is a pressure release valve. I have no idea about what level of pressure is supposed to trip it. (I would think not too much). No idea how you might test it.

At any rate, the part was relatively cheap and easy to replace. If you have it off and are concerned about it, chuck a new one in there. ( I hear the moan from people who loathe parts swappers, but I like to have my oil leaks fixed, and some piece of mind that my CCV vent is working properly)

I replaced mine (at time of CCV hose install) after talking with a fellow TDIclub member who mentioned that this part is prone to fail.


Not sure if that really helps, but that is my philosophy, and recommendation.

Good luck.

Regards,
Kurt
Austin, TX
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Here's how to test the CCV valve: Plug both inlet ports with your fingers and apply vacuum to the outlet port. You should hear air sucked in through the vent hole, feel the diaphram close, and when you remove vacuum from the outlet port (keeping inlets plugged), you should feel vacuum remain in the inlet ports for a few seconds.

Info for CCV draintube from IMPEX. Comes with all parts, ready to install. Just did mine and fixed my oil leak.

A3 CCV Draintube
Part number: 028103491J TUBE
Price: $35.30

You could really just remove that oil return tube and install a blanking plate over where the oil would return to in the engine and then get a Old Navy CCV with one arm. You would never need to mess with a cracked tube again.