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99 a6 audi quattro coolant leakage


My audi runs great. Its has 170K miles on it. My mechanic replaced an air pump last Friday and by Monday I had a new issue. I noticed coolant leaking. I took it back to the mechanic who fixed the airpump to diagnose. He tells me that the leak is coming from the timing belt/water pump area and in order to get there it takes 7 hrs. He suspects that its the water pump or a cylinder block crack. He suspects it could be a water pump breakdown more than a block crack. A block crack could be a serious issue with the engine is what I suspect.

I think he did something wrong when he replaced the air pump. He tells me that these are in two different areas and that he canbe generous with his time in only diagnosis but not in fixing the problem. Do you think he is right or is he lying?

He recommends that when they open the timing belt cover its best to replace the belt, tensioners, water pump etc. for a grand total of $1150. Now spending $1150 to get to know where the leak is sounds steep. Would any of you do it?

Any help?

I agree with him. To have the water pump shaft seal begin to seep coolant after 170,000 miles would be perfectly normal. That’s why most folks when the chenge timing belts also do the pump.

And, yeah, for an Audi the cost would not surprise me.


It’s entirely possible that the water pump has failed, and it has nothing to do with the air pump replacement. It seems unlikely replacing the air pump could damage the water pump. I’d let that one go.

I think the water pump has just gone ker-plunk. If it is original to car, getting 170k on it is an accomplishment. It was bound to fail sooner than later. I doubt it is a block crack, unless you’ve had prior overheating problems. Timing belts usually need replacement every 60 to 100K, so if you have close to that or more than that on your current one (I assume you’ve already replace it at least once) following yoru mechanics suggestion of replacing the water pump and timing belt , the tensioner, at the same time seems the right thing to do.

If your car as a Honda civic, $1150 would seem a little expensive. But for your model car, that seems a fairly reasonable price. I doubt you’ll find anyone who’ll offer a better bid. But it wouldn’t hurt to ask around if you want.

If you are continuing to drive this car – something I myself wouldn’t recommend – you need to be very careful to monitor the coolant temperature at all times until you get this fixed. If the temp suddenly goes up into the “hot” zone on the guage, pull over, turn the heater to “hi” and the heater fan to full on, and stop the engine immediately.

George: Helpful comments thank you. I have not had any prior overheating except once when I had to replace the radiator. I had to switch the heater fan and cool the temp gauge when I saw it rising above normal.I don’t think it would have affected the engine since I brought it right away to mechanic and got the radiator replaced. Alternatively I am thinking why not sell the car? Let the buyer deal with the coolant leak. Its not big by any means. The blue book is $4k. You think anyone would buy if I mention coolant leak.

Yes. But they’d want a discount of $1150 I expect.

It might be difficult to sell like that because the buyer would wonder whether the leak had resulted in an engine overheating.

On the other hand, based on some of the posts I’ve seen here, there are people who would nuy it sight-unseen just because they want to say they have an Audi.

I have been monitoring the loss of coolant every day. Its small - may be 25ml to 30ml. I do keep it topped. I have seen drips when the engine is hot and running. It does not drip when the engine is cut out and when its cold. It kind of proves that its not a crack in the engine block, does’nt it? Engine block cracks usually don"t leak when the engine is hot since metal expands and seals - right?. If that is so then a water pump seal leak becomes more plausible.

Any comments.

Where is the coolant leaking from, is it right from the belt end of the engine? If so, that’d be consistent with a failing water pump.

From what I’ve seen, the 7 hour estimate to replace the water pump sounds accurate. You basically have to remove the whole front of the car, bumper, lights, and all, to gain access. This is where a lot of the time/labor costs are involved, in removing all that, then putting it back when he’s done.

He is, therefore, correct to suggest doing the timing belt work at the same time. The procedure to get to the timing belt is the same as getting to the water pump, and the timing belt needs to be changed every 60,000 miles or so (or it risks catastrophic destruction of the engine).

You can borrow a leakdown pressure test tool from some chain parts stores. This will put pressure on joints or gaskets when cool and help localize the issue. A free test vs 1100$ i would go for the test. At this point the car will not last forever unless the wallet is brimming with cash. It is a judgement call that needs a clear goal.

Let me share a few data points when my mechanic tested for the problem. After the car engine was stopped and the car had cooled a little bit my mechanic attached a pressure device on to the opening of the coolant reservoir. He basically screwed the pump with a meter and pumped in pressure to see if the leak would happen. We waited for 15 mins. We did not see any drips. ( I was there.) He then started the car and raised the engine (speed and temp) the drips were noticed from the timing belt and water pump housing area.

He suspects the water pump more but he also added that it could be a crack in engine block but cannot confirm until he opens up the housing. That’s going to cost 1100 (opening plus replacement of parts).

I am trying to independently confirm and rule of the engine block crack. It does not seem to leak when the engine is cold. It does leak when the engine is running. Which seems to suggest seal in the water pump etc. What do you all think?