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Inoperative radiator fans, bad water pump, failed headgasket?
I'm not a mechanic but, I had to replace my radiator to fix the overheating problem on my 1994. That was the last thing I replaced after replacing the water pump, thermostat, and replaced my fan with a clutch fan. have not had anymore problems with it overheating once the radiator was replaced. Flush the coolant first then replace the radiator. Hope this helps.
Ingeneral, the fan will run only if the temperature of the radiator is above the normal range. If the fan is running, then the radiator must be over temp unless the radiator fan thermostat or it's relay is defective. If the radiator truly is over temp then you have a larger over-heating problem You state the thermostat was replaced. if you replaced the fan thermostat then either the radiator really is over temp and it is doing what it should, or there is a problem with the thermostat-fan relay or switch. If you replaced the engine thermostat that controls the flow of coolent between the engine and the radiator, then that probably wasn't your problem and you should look elsewhere for an overheating cause. I would start by determining if the engine actually is overheating or not. If it is, I would look for coolent system problems like the engine thermostat (if you didn't replace it already), water pump, leaks, scale build up in the radiator, or blockages in the system. If the engine isn't overheating then I would consentrate on the fan, fan thermostat and relays.
The top radiator hose is above the thermostat. If the top radiator hose is hot, the thermostat is opening. The thermostat is not the problem. Perhaps the radiator is clogged up or the water pump is bad. Look elsewhere.
are the cooling fans coming on
Your radiator might have a small pinhole in it, causing it to not build up pressure.
My 1990 Honda Civic Hatchback had a similar problem where it overheated on a seemingly random basis. I first replaced the thermostat, but that did not fix the problem. Then I replaced the water pump, again with no positive result. Finally, I replaced the radiator, which fixed the problem. As it turned out, the radiator had pinhole leaks that caused the problem. Also, when it comes to a leaking radiator, I do not suggest the 'quick fix' of additives to the radiator water that plug holes and stop leaks. These additives can cause more problems than they resolve. The best solution is to replace the radiator.
i would have replaced water pump long before replacing radiator. also check engine oil to see if it has engine coolant mixed in.if it has then the problem is more likely to be a bad head gasket
Same problem turned out to be a hair line fracture to the head!
likely possibilities are the following. Low or bad coolant , water pump, thermostat needs changing, clogged radiator or lines, coolant temperature sensor or radiator fans not coming on, head gasket Also check the radiator caps on the hose and the overflow container. That was my problem. One or both may have to be replaced.
Take your thermostat out and put everything back together, run your car without a thermostat... If your car no longer overheats, replace your thermostat.
Dirty or plugged radiator Water pump Defective radiator cap Thermostat Cooling fan not operating hoses collapsing