floatinghat

Ok, I was speaking to an independent mech the other day. He suggested replacing the water pump around 70-75K. Apperently he has seen the water pump seize and break the timing belt. Any truth to this He also stated that this in not something that Audi suggests but the water pump is much cheaper then a valve job.

April

Change coolant every 2 years. Use sacrificial anode to prevent electrolysis of dissimilar metals ( heads vs liners ).

You may want to look into another mechanic. The water pump is run by the accessory belt/serpentine belt. The timing belt is totally seperate and is cogged. Very few auto designs combine a water pump with the timing belt because of the seizure issue. Any knowledgable mechanic should be familiar with this principal.

To the best of my knowledge/memory ( I'm in Malaysia right now, and have no manuals ), the A8 does not differ from conventional design.

floatinghat

Thanks April, Interesting I'll look at that I thought it was strange. He stated that the smooth not cogged side of the timing belt ran the water pump. Water wetter is great I use in in my 71' 280sl. What you didn't travel to Malaysia with a full set of manuals?

muhammadc

When the timing belt is changed, a fair amount of the time, if the water pump isn't also changed, it will start leaking. I've got driving proof that this isn't always the case, but a few mechanics I've talked to say that this happens frequently, and I've talked to a couple people online that have had it happen, and paid labor twice in one week on the repair.

It is best to replace the timing belt, tensioner, water pump, and thermostat, at least, when you do the timing belt... since all of those items are related and close to each other. You won't pay a lot more labor to have them all done at once, but to have any one done is a 4-5 hour job.

Yes it's true if your water pump were to seize and break the timing belt, you would most likely do $3-$5k in damage to your engine (valves, among other things) within 1/10 second. Same applies for the belt breaking on its own.

I'm not sure if Audi yet recommends a timing belt replacement in the maintenance book (only in the repair manual do they) but it isn't the only item that should be service that Audi doesn't tell you about.

muhammadc

And yes, it's the smooth side that runs it. The different tension of a new timing belt when installed is what can cause the water pump to leak. I personally don't see a water pump seizing, but then again I'm no mechanic.

Andy P.

Yes, the water pump is driven from the smooth side of the belt, and the pump can seize up. It will make a mess of the belt if not sorted swiftly. This just happened on a friend's 2.8 V6 Audi 100.

Andy P.

ryoung

Thanks for mentioning this.

I've been pleased with the results when using Water Wetter in previous cars, but with Audi's somewhat of a not-invented-here attitude regarding the various fluids, I've been reluctant to use it my S8. Enough said, I added Water Wetter this afternoon.

April

Ahhh. Thank You Guys ! Seems backward to design it that way.

floatinghat

When should the water pump be replaced? I didn't ask if the rate $700 ish included the timing belt replacement. He felt this was a serious design flaw that Audi has not revised due to expense. ( I love it when old german guys get pissed about stuff like this reminds me of my father). He stated this is with all Audi V6 & V8's since 90'.

April

If you're in there, you may as well do it. Interval is 90K, right ? I would do it at 80K if so.