PJGross

Quick questions with detailed post to follow:

Anyone have the case of the electric waterpump fail (crack) spontaneously causing coolant to spew out during cool down mode with car off?

Are there any hoses connected for the inlet or outlet that, if pulled on, could crack the case, either when detailing the engine bay or doing timing belt service to the front of the engine?

Finally, what is an average cost to R&R this part?

--------------------------------
Now, here is the long story:
My wife's 2.7T, 95K miles, had a timing belt service and detailing which included engine bay detailing, done the first week of August (shop sends car out for detailing to a 3rd party).
October 10th she got a low coolant light and went back to the shop. They said there might have been an air bubble in the system, but they didn't see a leak so they topped off the reservoir.
This week the sensor came on again, and I noticed that when I drove it, after it was sitting you could smell coolant when you came back to the car. We set up an appointment for Friday. But, I noticed thursday that when sitting after warm shutdown, coolant would drip down about under the firewall area. However, with car running, no coolant leak. Wierd stuff. I didn't realize the A6 uses a secondary pump at the time. If they would have used a turbo timer I wouldn't be writing this.

Anyway, originally the shop said they would fix the coolant leak as part of the timing belt/waterpump repair from August, especially since they had a history of the leak.

Well, I was a little surprised when they told me we would have to pay for the "cracked case" of the electric water pump. Especially when the tech on the phone said that they had never seen this type of failure before. (The shop is a 15 yr plus Audi/VW specialist shop here in SE Michigan).

This got me thinking about the "failure". I've asked to see the failed part and will see it Monday. At this point I do not know if the housing is plastic or metal and where the crack occured.

However, I do know that we have a slow leak that drained the coolant resevoir in about 50 days after a timing belt/engine detail and that after filling, the leak drained the same tank in <30 days, with the last two days being near catostraphic failure. To me, this indicates a physical damage that with continued hot/cold cycling and pressure when pumping, fatigued to failure. And that failure follows an exponential curve of leak rate vs time.

If the housing is plastic and the leak occured at the base of a connection, I would say that some outside force on the connection fatigued/cracked the housing and continued cycling propogated the failure to its current state.

I've just never seen this part and anyone who has any experience with the electric water pump please add any information you can.

(Yes, my intent is to show that someone vs something cracked the housing during either detailing or timing belt change to avoid paying $700 to replace a part that a long time audi shop has never seen happen before)

Thanks,

PJ Gross

4Driver4

This is a common failure. The pump housings on the aux waterpumps have been failing like this since they were first used in the 1991 200 20vt.

Unlike the old 5 cylinders, your intake manifold has to come off to get to the pump. :-(

Truewit

Please have a look at my Tech write-up on replacing the water pump(www.audiworld.com/tech/eng69.shtml). The aux pump has an electric motor in a metal casing at one end and some plastic parts that incorporate the pump at the other. A crack is possible, though I don't see how 'detailing' could have been the cause of this, since the pump is located beneath the intake manifold and is not easy to access. As noted in my article, the original clamps securing the two hoses on my 2001 A6 2.7T were spring clamps, which could be the cause of a leak. It's probably not often absolutely clear if a leak derives from the hoses or the pump. But since the operation involves removing the manifold to get at it, it's safer just to replace it rather than discover at a later point that you need to do it again. If there is a crack in one of the plastic components, then replacement is the only answer. I'd recommend replacing the springs with screw type clamps in the process.

PJGross

Man, you guys are fast!

I did more searching under "auxiliary water pump" and found the 2.7T '01 tech article and the BaysideS4 write-up on this in the meantime and was just about to post a "nevermind" reply!

I agree, total coincidence as far as I can tell.

Thanks for the quick responses. I saw in the pics what I needed to reassure myself of no funny business.

Now I just need to decide whether $500 bucks is worth a vacation day and working in a cold garage!
Very easy R&R with the write-ups. However, our shop has been very good to us all along so I'd feel awkward pulling business after having them diagnose it.

I guess it pays to do research before taking action! Also, I would have to pass it by the wife, first, though. Besides a brake job, she doesn't want me touching her car. (I've swapped my tranny in my 1996 Impala SS myself but she's afraid that I'll install performance parts without her knowing it in her car)

Thanks again,

PJ

Eric 2.7

The pumps just disentegrate. I think all 2.7 elec coolant pumps will eventually fail.

absolutcq20v

<img src="http://home.comcast.net/~absolutcq20v/A6/auxpump/auxpump2.jpg">

...pump gets heated and cooled repeatedly, it ultimately fatigues the rubber and plastic bits, causing them to become brittle and crack. It's VERY common on the 2.7T. I just replaced mine a few weeks ago; click the link below to that post and more pictures.<ul><li><a href="https://forums.audiworld.com/a6/msgs/566721.phtml">Coolant Pump Replacement</a></li></ul>

GP2.7T

Mine Failed after 2yrs &amp; 40K Miles

PJGross

Thanks to this forum and the tech articles, I just saved a bunch of labor money!

I started at 7PM last night, got done about 1AM. I wrote every connection and took picks so speed wasn't my goal.

Anyway, the pump was leaking at its clamshell joint, right in the middle. Pretty obvious.

This is a pretty straightforward R&amp;R. I would just caution anyone with lower back problems to get someone to trade turns with you. My back was killin me about the time I was putting in the manifold bolts!

Oh, and if you're not a pro at guessing torque, use a torque wrench! The manifold bolts don't need a ton of torque.

Weekend mechanic scale of 1-10 in difficulty...I'd give it a 6 only b/c there is a risk of dropping things where you might not get them back easily. Otherwise, it'd be a 3.

Thanks,

PJ

absolutcq20v

The manifold bolt torque was only 7 Nm, IIRC...or a little over 5 ft-lbs. I'd like to reiterate that a magnet wand is ESSENTIAL, as I dropped a few bolts into the abyss that is the 2.7T that would be lost without 'magic' wand. :P