sheepers

Hi ~

I just bought an A6 that is leakikng a qt of oil every 15 mins under load. The leak is slower at idle, and even slower when it's off.

So, after a little bit of clean up and dye/black light investigation, I am seeing leak in the front of the engine, either from the Crank Seal, or the upper oil pan/block seal , in the dead center.

The flywheel blocks the viiew of the uppper oil pan/block seal, and it's really hard to see the dye to confirm the source of leak.

The last owner drove over the oil cap , so the car have been driven a short while without a sealing oil cap.

Now the questions...
1. Without a sealing oil cap, the I think the PCV system does not have vacuum, and thus the crank builds pressure. But 1 qt after 15 minutes of driving?
2. The car has a 2 year old breather tube, not clear if the PCV valve / vacuum jet pump was installed though. Can I at least rule out pressure build up problem by running the car with the dip stick out to avoid pressue in crank and see if there is leak?
3. At this point, the lock carrier is in service position. If I have to gamble and address either 1 of the possiblities, which one should I do first?
-replacing upper oil pan seal will involve hoisting engine, lower subframe , remove lower pan, then upper pan.
-replacing crank seal will involve remove both valve cover, remove timing belt, remove crank.
4. The timing belt / water pump were changed 1.5 year, 20k miles ago, so it's not due yet. I don't want to change the water pump, may be just the belt.. Where can I rent the tool? blauparts would be my choice, but I don't need their whole timing belt kit.
5. Now that the lock carrier is in the service position, coolant line is drained and disconnected, can i hook up a air compressor to the dip stick tube and apply some air pressure to speed up the leak and hopefully I can see the leak under black light?

Thanks!

4Driver4

It's neither. It's a high pressure leak. Check the oil pressure switch.

sheepers

Can you elaborate more? Isn't the oil pressure switch responsible for turning on the oil warning light on the dash?
Is there a oil relief valve in this engine?

Should I check for oil pressure ?

sheepers

I removed the crank pulley and confirmed that oil is leaking from the crank oil seal, not from the upper pan gasket.

Now the question is ... what do I do ?

Given the timing belt is only 2 years old w/ 20k miles,
I'm tempted to just remove the crank sprocket without any special tool, without setting TDC, just compress the tensioner, jam the fly wheel with a screw driver, remove the crank sprocket, and use a screw to extract oil seal.

Is that dangerous?

4Driver4

Why not use the proper tools and take the opportunity to re-set cam timing?

JerzyBoy973

I did my timing belt without the tool, using a ton of reference marks and it wasn't as dangerous as people have said. But I haven't removed the crank sprocket. I suppose if you marked it in reference to the timing belt in addition reference marks on the cam gears and corresponding belt teeth (I did 2 marks per cam gear) everything will be in order. I also marked the cam gears in reference to the face of the motor just in case. Using the tool is safer and faster, but white out is cheaper and you don't have to wait for it to be shipped to you.

PS. If your timing is slightly off, you'd be missing an opportunity to reset it as 4driver4 has pointed out.

4Driver4

It's not that it's dangerous, it's just that your timing is probably not set right. Putting it back together exactly as it was doesn't mean that the timing is right...even if it was set perfectly before you took it apart.

frankinstyn

I don't agree with you here. The closest you are going to get your timing is on the correct tooth. After that there isn't anything you can do. As long as the cams and crank are on the correct tooth everything else is set by the computer.

Also, if his timing was off the computer would tell you and a code would flash. I've removed my timing belt three times (two timing belts and one bad thermostat) now and no codes and no loss of power. I have yet to get the tool.

If Audi intended the timing to be so incredibly accurate it would have opted for either a chain or timing gears (like a diesel). Are engines just aren't that fine a technology.

4Driver4

What you have written is abolsutely true...for the 1.8 and the 3.0. However, it is absolutely false for the 2.7, 2.8 and the 4.2.

The exhaust cams are driven directly by the belt; there is no way for the computer to adjust this. The only way to adjust exhaust cam timing is to break the sprockets free and set it. Further, exhaust cam timing is infinitely adjustable; there is no way for the belt to be "off a tooth". The bar is used to set timing correctly. If you don't use the bar and put the new belt on as the old one was, you will be close, but probably not perfect. For the amount of work involved, it is a poor practice to get it "close enough."

Yes, having the timing waaaaay off on the exhaust cams will throw a CEL, but timing can be off and power and economy impacted long before timing is out enough to throw a CEL.

Audi did intend for the timing to be accurate. They specify that timing be adjusted when the belt is serviced. You may be happy with your car, but chances are that at least one of the exhaust cams is off at least a few degrees.

JerzyBoy973

I'm guessing you're talking the gears getting slightly out of sync due to stretch in the belt over time?

Installing a new belt by using the tooth indexing method would correct any such deviation since the new belt is at the correct length and will pulling the gears back slightly to their correct places. It's just as accurate as using the tool since you're marking and counting teeth (and toothed belts don't slip).

I had a long conversation with an Audi Tech at my nearby dealer before before tackling my timing belt. I would never have tried it if there was a chance to get it wrong (without blatantly fuqqing up).

This is all of course my opinion and everyone is entitled to their own. I just don't see how much better the timing could get since if you're off by just one tooth you'd be screwed. Dead on is dead on IMO.