Coolant Expansion Tank Replacement: Take 3

[Guest]

I want to start by thanking they guys who posted the original thread on this topic which can be found here:

http://www.renntech.org/forums/index.php?s...c=6675&st=0

It was a big help the first time I did this job. It was a bit of work, but I did have the advantage of having the tool to uncompress the hose clamp and was easily able to loosen the hose. I went in right from the top, I didn't even contemplate jacking the car. From the passenger side I was able to reach down and get the tool on the clamp by snaking it through from the opposite (driver's) side of the car.

The first time I did the tank it only took about 1 hour and 40 minutes. That tank lasted a whole week before it failed. This time in a completely different place than the original, but it failed.

So we talked to the shop and they agreed that that was Bull$h!t and they ordered up another tank for us at no charge. So the second time around I was able to get the tank in in a mere 45 minutes. The second time was a breeze as I knew all the proper contortions and had the cracked one out of the car 10 minutes after draining the thing. A few minutes later I was topping up the tank, pulling the bleed valve up and running the heat up to wow.

I got the system fully bled and all was dandy. So it's been about 5 weeks and tonight after coming home from dinner my wife looks down under the rear passenger wheel and sure enough, there's that familiar puddle under the wheel. **** IT! I put my hand into the trunk and I didn't have to rub my hand across the carpet long before I felt the dampness. The stench of ethelene glycol was enough to choke a horse.

So we'll be calling up the parts desk again on Monday to get another (yes count 'em... one.. two.. three) tank. The third in just 2 months.

I'm actually starting to get pretty pissed off here. I'm a **** careful mechanic. I use a torque wrench on everything and I have been very gentle with the installation of these tanks. They just keep failing.

Now we drive the car harder than most, but we don't abuse it or bounce it off curbs.

Has anyone else seen this sort of issue with these **** expansion tanks?

[wvicary]

I've replaced a few of these tanks and not had a replacement fail yet- touch wood - are you buying the OEM tanks or are these some sort of aftermarket tanks?

Just a thought, possible headgasket failure and compression gasses are getting into the cooling system and damaging the tank. Might be something to look into.

[slbates]

Are you positive it is the tank? Did you replace the spring clamps with the screw type clamps in the TSB? I had trouble with the spring clamp leaking after a tank install on my 996. Screw clamps ordered from the TSB solved the problem.