Overheating car?

Question

My 2004 Honda civic overheats. Only after coming down from highway speeds to stop sign speeds. My fans work, I have replaced the radiator, replaced thermostats, bled the radiator, and some people say it could be a blown head gasket, but the oil is not milky, nor is there any combustion gasses coming from the radiator cap. I think it might be a wrong radiator cap, but not sure yet, because i have replaced the radiator twice. Oh and after it overheated, i noticed the reseivor was full and the actual radiator was empty. So it is obviously overheating from leaking coolant, but we did a pressure test and a vigorous check of all the hoses and found no leaks. HELP ME!

Thanks.

Answer 1

It is not a headgasket, if that were the case you would have white smoke coming out of your muffler, and like you said your oil is not milky. If no coolant is entering the radiator than you most likely have a bad thermostat. I know you stated that you had it replaced, but don't trust mechanics, they are scum (im not a mechanic, just a hands on do it yourself guy). A thermostat is fairly easy to remove, just upper rad. hose, and two bolts are the only thing attached to it, well depends car. I suggest check out thermostat. A trick I use to check if thermostat works is, remove it, place it in a pot with water, boil the water with thermostat in it.  If the thermostat is working properly than it will pop open when the water is boiling.  If everything else works, than I am pretty sure you have a heat sensor that is not functioning properly.  Be advised, I am NOT a mechanic, but have had these things happen before. I suggest you buy car manual that shows you how to troubleshoot your car. Or just take it to a trusted mechanic.

PS: My car problem was similar to yours but it turned out at the end that all I had was a bad sensor.

Answer 2

My car was overheating and the fan was kicking in for ages. I kept filling my water tank up but it kept emptying. My oil was all gungy so my water was obviously mixing with my oil. I had nothing perculiar coming from my exhaust.

My cylinder head gasket had blown. I had to pay £550 for a new one. Any of my cars symptoms sound the same as yours?

Answer 3

Have you checked the thermostat

Answer 4

Sounds like a headgasket. Check Kragen for stuff in limegreen bottle, it works well and costs about $22-24. Its better than $500 at a shop.

Answer 5

definitely sounds like a radiator cap.

the cap has a valve in it so that when the coolant heats up and expands it flows out into the reservoir then when it cools down the coolant gets sucked back into the radiator.

i would replace the radiator cap then recheck it.  you are obviously losing coolant, but it could be bubbling out through the top of the reservoir.

Answer 6

sounds like its just a piece of c**p, Run it off a mountain

Answer 7

Head gasket needs replacement. The car is burning/losing the coolant thru the motor.