I just had a new 6 bolt bottom end put in my '97 TSi and about a week after it was done it started leaking oil fairly drastically.

It leaks worst at RPMs over about 3500 (virtually blasts out at 6k RPM) and is a slow but steady drip even at idle after the car reaches operating temperature. Just as an example, during a 20 minute drive with some 'spirited' acceleration, the car went through about 2-1/2 liters of oil. Enough that it even coated the rear bodywork above the exaust.

From what I can tell from beneath the car, the oil is dropping from the area between the lower t-belt cover and the driver's side edge of the oil pan. I tried snugging up the oil pan bolts but it made no difference whatsoever.

The massive leak occurs within seconds of revving the car to 6000rpm, which leads me to believe that the leak is not too much higher on the engine and then leaking down.

My current theories are these;
1. Front cover gasket.
2. Front crank seal.
3. Oil filter housing ("oil pump") gasket (I swapped to a '90 ext. oil cooler setup.)

Despite the oil leak, the timing belt (and all accessory belts) is completely dry. Also, there is no oil spraying onto the alternator or any other parts visible from above the engine.

Does the dry timing belt eliminate any of my three theories?

Throw you're car up on stands and leave it in neutral. Have someone (if possible) rev your engine up and you sit underneath and see where it's coming from.

Another idea would be to get some dye to find leaks. Throw some into your oil and that will better show where it's coming from.

No offence but sitting under a car thats on stands while your buddy revs it up is kinda of risky. If you feel safe doing that go for it... But I wouldn't do it.

I didn't mean get right under the car, but lay down in front of it, beside it, wherever. I wouldn't even recommend laying underneath the car while someone is revving it up.

Sorry 'boot dat...

I have the exact same problem. Looks like the front cover gasket is leaking. I reused the old one.

Wade, you're going to have to remove the timing belt cover to actually see anything. You can remove all the accessories and timing belt cover and run the car without them for a minute or so to see the leak properly. Don't run it beyond that, as it will overheat without the water pump spinning. I would buy all of the gaskets (oil pump cover, crank seal, etc. while you were at it, they're not too pricey) and swap them all out anyway. As another possibility, if the balance shafts were removed when you installed this motor, it could be that the hole in the oil pump cover wasn't properly sealed.

Thanks for the quick information, guys.

Matt and Ryan, I've revved the car up to 6000 on stands and then 'ran' back under to see what the effect was, the location of the leak still isn't obvious. I think (as Michael suggested) it's unfortunately concealed by the lower t-belt cover.

Right now I'm just wondering if the fact that the t-belt itself is completely dry eliminates, say, the crank seal as a possibility, i.e. a leaky crank seal would DEFINITELY blow oil onto the belt? It just seems odd that the oil seems to be flooding from behind that cover (where the belt is) yet there's not even a spot of oil on the belt.

To Michael Z., the mechanic who did the swap for me said that the balance shafts were only 'half' removed. I think the one shaft is still in there, but the pulley was just taken off to prevent it from spinning.

The front cover seal appeared to be in good shape when I bought the bottom end complete from a fellow in Ohio. I'm 99% sure that they used a new gasket, at least.

Right now I'm strongly suspecting something to do with the oil filter housing. Perhaps that hole that Michael suggested is the problem? The hole would leak oil in behind the oil filter housing, correct? Wouldn't this oil be prevented from leaking out by the gasket, then?

Does the rear of the oil filter housing extend into/behind the lower t-belt cover? I'll have to look at the diagrams on the Tech CD when I get home tonight.

I have an appointment with a local mechanic to check it out on Tuesday, July 4th, but if I can figure out what it is (or certainly is not) before that I can at least give them proper instructions and/or prevent being clipped for something that's not actually the problem.

If it's leaking behind the cover - then to fix it, off comes the cover (at least partially).

You could pull the crank pulley off and do the dye thing. With the lower tb cover bolts out you could pry the cover back and take a peek to see if it is the filter housing or something else - then you'll know what direction to go from there.

Don't mean to hijack but again have similar problems on my new 2.4.
As for the plastic timing cover seals their should not be any oil under timing cover.Now front case gasket could leak.You would think a front main seal would drench the belt.And a balance shaft pulley leak would think would also drench the belts.

I have similar things.I have dry timing and other belts and not losing near as much oil as you but still quite a bit a quart every couple days depending on how much driving I am doing.

I seem to have lots of oil coming thru the oil pan,never using topline oil pan gasket again!

Oh I also installed a 90 oil filter housing.
Is the gasket that came with the basic kit wrong of the 90 wondering about that if it needs a 90 gasket? Anyone know if the 90 gasket is different from 91 up?

From what I can tell in CAPS, the gasket changed with the 7-bolt.
Although there are 2 part numbers listed for the '90 (MD041018 & MD149370) but I think they are the same part.
91+ 6-bolt is MD149370, and the 7-bolt (all years) is MD185528.

it is not the valve cover for sure?

Valve cover beside the cam gears, can drop a lot of oil down to the bottom of the lower timing cover. Would be easy to tell with the upper cover off.

And check out the oil pressure switch & oil pressure sending unit while you're at it...
Thoes can leak at the threads and it may not be obvious.

Thanks guys, you've all given me some good ideas of things to check for.

- Valve cover at cam gear end.
- Oil pressure sensors.
- Oil filter housing including banjo bolts for ext. oil cooler lines.
- As much front cover joint as I can see.

I'll go under the car again tonight and post an update tomorrow.

I'm going to hold off on removing the lower t-belt cover for now. Might not have enough time after work before dark.

I took another look last night and I'm now about 70% sure that at least part of the problem is the oil pan gasket.

I jacked it up, revved it and then went back to look under the car and I'm pretty sure I saw some tiny little oil 'gurgles' at one part of the gasket. So that's the first thing I'm going to try. Cheap and easy so, if it's not the true problem, at least I'm not out much time or money.

Thanks for everyone's help and I'll post back once the gasket is done, either for more help or to let future searchers know that the oil pan gasket WAS the culprit.

You are doing the same steps i did. I am riping mine apart tonight. I will post the results.

Crank seal.

Don't say that, Mike. Those are hurtful words.

(figers crossed)

hurtful?!?! It is easy to swap in a new one. you can pull it out without taking off the front cover.
did the front cover come off when the work was done?

Doesn't a leaking crank seal get oil on the belts?

Would think it would.

I would defiently be changing that timing belt, and balance belt if installed.

Well, here's the bottom line. Whoever rebuilt the block (which I purchased complete from a gentleman in Ohio) didn't seal the cap over the front balance shaft hole on the front cover good enough. The cap came out and then so did all of my oil. I don't know how the metal cap didn't foul up the t-belt. I really don't know how no oil got on the t-belt considering that this all seemed to happen within the t-blt cover. Anyway, it's fixed now and I'm happy.

Part number for new cap was...

MD092785
Balance shaft
cap (plug)