Hey all, was on the forums a few weeks ago for an overflowing coolant reservoir. Changed the cap, problem went away for about a week. To my knowledge, fan is good, radiator is good (though I am flushing it in a few days), and the thermostat has been removed, so I knew it couldn't be any of those. A week later, problems have come back and the coolant reservoir overflows until the fan kicks on, then the coolant is sucked back in. I now believe that there's a breach in the head gasket somewhere, and plan to change this out soon. My question is this, how is it that replacing the cap made the problem subside for a few days, only for it to return? Is this a sign that the condition of the gasket is worsening? Or has this happened to someone and it's not the head gasket at all? I will do a leak down test tomorrow when the kit arrives. I want to be sure that when I do replace the head gasket the problems don't reappear. I will admit, I don't know if the car overheated before I began driving it, and if over time the head gasket has been slowly going out due to overheating. Its been driving fine for the past year, which is why the sudden emergence of this stumps me. Thanks

 

It's an old car - stuff happens, I'm sure that engine has been overheated at least a few times over the years after cooling stuff has broken. It just takes a few minutes without coolant to damage something. Eventually the head gasket will have problems. Not a big deal. Hopefully things will be better AFTER the head is straightened (not just surfaced) and a new gasket is installed.

 

It is puzzling what you describe. But do the leak down test, then you'll know for sure. HG are tricky, they separate water from air and oil, and this can create sometimes weird results. If you do need to do the HG but not want to go too deep in, I have had great results with Blue Devil additive which works well for some HG issues.