So I have had my coolant "boil over" a few times in the past week.

Engine temp sensor is not going over 200-210*.

I replaced the radiator cap hoping the old one was worn out.

It boiled over again today.

I am now thinking that I have a hole in the headgasket near a water jacket which is pressurizing the coolant system and "boiling it over".

Are there any other possible ideas?

Will a compression check show this? Or do I need to do a leakdown check?
My thinking is that its a small hole, and a compression check might not show it......


help please.

compression test would tell u something there should b a diff. in the cylenders

sounds like a head gasket though

Yeah, the only thing is that it doesn't do it every time I drive the car, and other than it spilling out of the over flow, it drives fine.

does the car overheat(temp gauge may not be accurate.) lack of power? is it adding oil to itself?

It does not seem to do either right now.

check the radiator when cool. start up the car with the radiator cap off. if there are lots of bubbles its a good indication of a blown head gasket. check the oil. might have a tint of green or red. depending on the color of antifreeze you use.
also what is the color of the smoke comming out of the tale pipe thats a good indication also.

Oil is normal, no increase or color change.

Exhaust seems normal, no tint or smell.

You can rent a tool at Autozone that you put over where the radiator cap fits. You pump it up to around 11 or 12 pounds. Then start the car. Pressure should come up some and hold. If pressure continues to build then you know there is a head gasket or head problem. If you return the tool its free to rent. They will tell you there how to do the test. I just gave you some basics.

Best way to check for a blown head gasket is perform a block test, but you a block test kit to do this. I got mine from a auto parts store for about $40.

Most likely its a bad thermostat.

Can cause engine to push water out because it is not opening at the right time.

It is easy to change and cheap!

If you have water/antifreeze in your oil, it will look like milk.

i agree on the radiator pressure test. but also check the level. cars tend to boil over more if the level is low. also check the weap hole on the water pump to see if its leaking.. didn't think about it.. but could be a failing water pump.

The car isn't overheating at all, could the thermostat possibly be bad?

I guess I dont understand how that could work......

guess so. it can fail closed. have you checked the coolant level yet?
ive seen them both fail open and closed. failing closed will cause over heating symptoms.