so ... i am still having issues. it took a little longer for it to happen this time but i havent really drove the car in over a week because i needed to conserve gas.
so far i have done these things
- pressure tested coolant system up to 20lbs , system held pressure
- pressure tested radiator cap, cap held pressure right up to 16 lbs , which the cap is rated for
- replaced the line going from the rad to the overflow tank and secured all the connections.
- tightened up the thermostat inlet after the gasket set
- checked the mating surface that the radiator cap seals too, there a was a little blemish that almost looks like a very small hole, and some crusty dried coolant. but if this was an issue wouldn't the coolant pressure test have failed?
You're not going to want to hear this, but I've seen that before and it was a blown head gasket. It was letting combustion gasses in the cooling system, blowing out the coolant, and causing the car to overheat. This was on my brother's '95 GT. We chased the problem for a while and ended having to pulling the heads as a last resort and sure enough and small leak in the passenger head gasket.
You could use a leak down test to determine if that's the problem or not.
looks like im going to have to explore this option
Did you replace the radiator cap with a factory replacement? I replaced my stock one with a new ford racing radiator cap, it caused the same exact problem. I reinstalled the stock one, and it was working nicely again.
i got some cheesy replacement from autozone that had a weird pressure releasing valve on it, which a tech from work said was definitely the wrong one. im going to try to get one that looks like mine and try that even tho it passed the pressure test
Start with the radiator cap and the radiator filler neck. There are 2 seals on the radiator cap.
One seal is for the coolant inside the radiator and It is spring loaded closed and remains closed until the pressure inside the radiator reaches the pressure marked on the cap. Then it vents coolant to the overflow side of the cap
The other seal is the filler neck seal that insures that the coolant that overflows the radiator goes to the overflow tank. It is also responsible for maintaining the vacuum so that the coolant gets sucked out of the overflow tank and back into the radiator when the engine cools down..
Check both the seals and the metal surfaces they seat against for damage or evidence of leaks.
If you have an air compressor, there are a couple of other things to try. If you don't find anything wrong with the radiator cap or the radiator filler neck, repost and we'll try some of them.
I checked this out and noticed something... but it passed the pressure test so im confused. ive included a picture of the spot where it almost looks like there is a pinhole sized hole and some coolant dried up and i scraped it away (the white stuff was coolant)
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