Questionmy car over heats but does not leak antifreeze our spill over out of over flow there is no pressure in the system the top radiotor hose never has pressure either does bottom took out thermostat still no pressure but will over heat gets so hot shutdown relay with shut off car i could have the temp gage at halfway mark and unbolt thermostat housing with no pressure bubbling out at me
AnswerHi Jon:
Thanks for the generous ratings. But I still can't tell you exactly why the car is overheating:
You didn't tell me about the cooling fans coming on or not coming on. Can you tell me how you measured 240 degrees, or with which gaugs? What relays overheat?
On the overflow bottle: you said that it will bubble over if filled beyond the cold fill line: well that is an exact showing that the system IS pressurizing and releasing steam via the radiator cap, and that steam is routed to the overflow from the radiator cap opening. So it indeed appears that the system is pressurized enough to blow open the radiator cap. I can't be sure about the upper radiator hose, it may have a concave appearance even though the pressure is greater that ambient if the rubber is very stiff.
You didn't tell me how much coolant you are using each day or week or per mile of driving. Can you tell me that? When you start the car from a cold condition do you see any white smoke coming from the tail pipe, and if so does it smell like coolant (that would be a sign of a head gasket leak). How quickly after you start the car from cold does it overheat? Will it overheat just idling? And again how about the fans?
You do have a cooling problem but I can't be sure what exactly it might be without answers to these questions.
It could be you have a headgasket leak (also how does the oil appear to you?). You may have a faulty radiator (needs cleaning?). Your water pump impeller may be loose(hard to diagnose without removal, is expensive repair). Your thermostat may be opening at too high a temperature (have you removed it and tried to heat it in a pan of water to see at what temp it begins to open?) There are a great many possibilies so you may just have to go thru each to find out the specific causes. Are sure that the radiator is filled to the cap opening and then that additinal ooolant is filled to line of the overflow bottle?
I think you may need to go to a radiator shop to have it analyzed, Jon, unless you want to do all the tests yourself and also to write back and tell me about each of the questions I have asked you.
Roland
Jon responded:
it will get up to 240 degrees the relays get so hot the open circiut and will work again when cooled down our pulled and put back if i fill over flow all the way up past could fill line it will bubble over but biggest problem in my mind is the upper radiator hose does not have pressur nor does the raditor overflow witch is a pressurized cap
Hi Jon,
That sounds very fishy to me. Is either radiator fan coming on (when you are NOT using the A/C) when you believe it is overheating. On what basis do you believe that it is overheating? Is it the temperature gauge reading off scale?, is it releasing steam to the overflow bottle? Can you put a meat thermometer or other thermometer in the cooling system filler (since you say that there in no pressure) and actually measure the temp of the coolant? I suspect that you are being faked out by your temperature gauge (faulty sensor) if there is no steam blowout somewhere. And you aren't having to add coolant to the system? There is no shutdown relay response to high temperature; it only will shut off the car if the crank or cam sensor signal is not present. So that is not proof of overheating. Nothing is automatically going to stop the engine when it overheats except serious engine damage and then of course it will stop. But I don't see any evidence for overheating.
Please respond to my questions via the "thank and rate" tab, as I am only taking one question a day at this time.
I will get an alert that you responded with the answers and write you back.
Roland
