brickers:

having some odd issues with my coolant overflowing from the expansion tank and wondering if anyone has an idea why this might happen.

I popped the hood of my 745t after a quick run to town and found liquid all around the expansion tank. I first thought it was water that had splashed in from some large puddles I had come through on my way to the house, but quickly realized it was coolantgiven the location and area.

The top of the expansion tank was firmly tightened, but the coolant had apparentkly shot out through the cap. I'm guessing it came through a pressure triggered release in the cap itself... I don't know that the cap has this feature, but a glance appears to indicate it does and it would make sense to have a release to prevent pressure from possibly causing teh radiator to explode.

I'm currently living on a ski mountain in VT, and the drive back from town involves a 3 mile section up a fairly serious hill (maybe 30 degrees or so with some intermittent flats on the way). I generally take the hill at around 60mph, with some minimal turbo boost utilized.

As a test I checked the coolant this morning and repeated the trip while closely monitoring the temp gauge. The trip to town went fine, with the gauge needle staying around 11 oclock (its normal position). However, on my way back on the uphill the gauge climbed to 12 oclock and seemed to border on wanting to go higher. Since the only time it rises above 12 oclock is when it starts to seriously overheat this got me a little nervous.

Anyone know if there is a problem I should be aware or why this might have happened? I flushed the coolant about 4.5 months ago or so and haven'thad any trouble since despite the fact that I've driven a 3 hour, 200 mile trip 15 times with an average speed of 70mph or so. When I flushed it I checked the stat and it looked like new. The radiator has a pinhole leak that I used some radiator patching mixture to fix (the gunk you pour in the expansion tank, etc.). Yes, I know I need to replace the radiator and shouldn't use the goo, but I think it would have bugged out earlier if this was the source of the problem.

Any help or thoughts are greatly appreciated.

Thanks,
Rick