Radiator leak -cap High pressure head gasket leak

[crobertson]

I have a weird issue with my radiator leaking. It appears to be coming out around the radiator cap. I change the cap and appears to continue to leak occasionally. The temperature never really raises above half way (operating temperature). If you fill the reservoir, after pushing the car, it will push about 3/4 of the fluid out.

I've run into this before on other vehicles I've worked on and learned long ago this was typical of a high pressure leak in the head gasket. I haven't done a leak test yet, but last time I had this issue none of the cylinders leaked down faster than others. I ended up replacing the head gasket and that fixed it.

I'm attempting to avoid the inevitable and hoping someone has another reason.

[frapjap]

Welcome to NICO!
That is an interesting problem you're having there. It sounds almost like you have air n the cooling system. You seem mechanically inclined, so I'll suggest that you raise the front end, remove the cap, and let the engine run through a few fan on/off cycles to see if you can remove any extra air. Drive it again and see if anything has improved.

Other than that, it wouldn't hurt to do a leak down test.

How many miles are on your engine? When did you last do the head gaskets?

[crobertson]

Thanks for the reply. First the car has 185k, never changed head gasket on this car. It's a new car to me. I do a bit of mechanic work, but am not a mechanic.
Yes, I think I'm getting air into the cooling system from a head gasket leak. I've already ran it without the cap and nothing much happened. It only happens when I push the car hard, so it doesn't do it often. I've done leak down test, Just haven't on this car. It looks like I will be doing a compression & leak-down test.

[audtatious]

Any frothing in the oil or coolant smell from the exhaust? If it is a HG issue and simply rolling the car can cause it to blow water then you should have coolant/sweet smell from the exhaust at least.