Car had been parked for about a week at the airport while I was out of town. On the way home I noticed it was running just a little hot but not outside the "180" band.

Later that night (maybe 2 hours so it had cooled a little) I went out to get some takeout and within about 1 mile I was stopped at a light when I noticed a coolant smell. Temp was still okay though.
I drove about another three miles to the sushi joint parked with the engine running and got out. I immediately noticed a significant stream of coolant dumping onto the drivers side exhaust and a trail of coolant leading into the lot. Uh-oh.

Turned off the car and got the food, I came out and the flow of coolant had stopped. Temps were still okay.

I drove home and the same thing happened. With the car running quite a bit of coolant is leaking out but when I pulled in the garage and shut it down it dripped a little more (maybe 30 ml) and stopped.

I could NOT see where the leak was coming from but it looked like at least some was coming out from the blue cap and going into the overflow tray and drain tube. The pressure relief valve above the expansion tank was in the "up" position (I assume this means it is under pressure?) where the little metal clip could rotate freely without having to lock it into the up position.

The next day I checked coolant level in the reservoir and it was showing within range. Bizarre but i guess there could be an air bubble in there somewhere.

So I started the car and let it warm up, even after 30 minutes of idling and revving engine the display never got above the 180 mark. It also did not dump any more coolant.

I know the pump is functioning since you can see the main expansion area fill and surge as the engine is revved, after the car was warm the smaller "filling area" did drop below minimum arrow but no more coolant would leak out of the system and the car would not overheat.

No leaks are apparent at any of the hoses.

I'm friggin stumped on this one and need some help.

Possibly relevant info:
expansion tank replaced in 2004
water pump replaced in August 2007
no issues with temp after any recent maint.

TIA,
Keith

 

When you replaced the expansion tank, did you also replace the Cap? Th original caps were prone to leaking. The new cap part number ends in 01.

 

Hey Tim,
No I did not. Just checked and I do have the cap ending in "0".

I'll order one tomorrow as it's definitely worth a shot.

Thanks, Keith

 

Keith,

That is most likely the cause of the problem. If not, then I suspect it could be the expansion tank again. Let us know if the new cap corrects the problem.

 

Hey Tim,
thanks for the help....this was close to the cheapest repair yet.

The new coolant cap seems to have fixed it, and it's now at revision "02".

 

Glad that fixed it. Thanks for the heads up on the "02" version. This is the first I have heard of that version.