Dumping coolant

[aps1231]

Allen,

I'm facing a similar problem (See thread "Mysterious coolant leak").

In my case, coolant is dumping around the right rear axle area, which seems to be an overflow from the expansion tank.

We replaced thermostat, pressure cap and bleeder valve, but that didn't fix the problem.

Two possibilities:

1/- Air pocket in the coolant system expanding with the heat, pushes the coolant up thru the pressure cap and overflow. Solution: check that the coolant system is purged from any air, thru the bleeder valve (Use "vacuum method")

2/- The dreadful but less likely head gasket leak (seems to be a favorite among some in the industry). Have exhaust gases analyzed for water vapor and coolant analyzed for presence of hydro-carbons.

I'm not an expert, but this is where I'm at right now. I'm getting the car back to the shop tomorrow to investigate the above possibilities.

Good luck and let the rest of us know what you find out.

Alain

[aps1231]

And I like explanation #1 better, because it's a lot cheaper to fix, and also it may explain why the problem I have is intermittent. Indeed, depending where the air bubble is trapped, it may be exposed to higher or lower temperatures, thus resulting in more or less expansion. I assume the air bubble would move. Again, I don't know much about engines, but...

[chris64]

I test drove a 2004 S with less than 20 k. After driving about 10 miles and parking, roughly a cup of coolant dumped on ground near right rear. The over flow tank showed way more than max fluid level in the tank. The reservoir cap was tight and the carpet in the trunk felt dry. The dealer mechanic racked it and could not find a source or repeat the problem. I love the car but this is a bit of a red flag.

Dealer is offering a 30day 100% warranty and a 5 day 100% refund. Worth the risk?

[rick3000]

I had the exact same thing happen to me. I pulled into the garage, shut the car off and all the coolant drained out.
I freaked out and took it to the dealer and $600 later nothing was wrong. It was just an air bubble in the coolant tank, and it all drained out of the coolant overflow above the right rear tire. Refill the coolant and don't worry about it.