Expert: Sean Halliday - 8/31/2009

Question
I have a 1999 Ford Taurus with a boil over problem. I change the expansion tank and cap (twice) not long ago. It boils over out the cap after a few minutes of hard driving. Any high temp. does not show up on the gauge, it stays in the normal range. I removed the cap and started with a cool engine. At idle the coolant is around 160 degrees in the tank. I took up the RPM's and it went up to about 180 degrees. It was fine until I took my foot off the gas. Coolant came shooting out of the tank. Is that normal?

Answer
It sounds like you have a leak at the head gasket.It is most likely blown across the water jacket,hence too much compression in the cooling system.You can confirm this by doing a leak down test.This test must be done by a shop or if you have a compressor source,you can do it yourself.