96 honda accord running hot cant figure out why
 

96 Honda accord automatic, 152k, it has a 2.2 vtec, the head that is in it is not original nor is the radiator, I put a new thermostat in it, the hoses are good, fans are running, radiator hoses on top and bottom are hot BUT it runs smoothly cranks easily.Drives like a brand new car.
Problem is it tries to run hot after driving about 3 miles. For about two miles it stays a little below half then it starts to climb somewhat rapidly, within a mile, its to the red. I have never let it run hot. I pulled over and let it cool off. Both fans were running after I turned the car off. Ac didnt seem to work however. I just got this car a few days ago. Guy I bought it from said its been parked for 5 months. Prior to this he bought it, drove it home about an hour away with no problems, gave it to his daughter age 16 she immediately hated it when she looked at it which I do not know why the body is perfect on it and never drove it. As a matter of fact, he never touched it again until I had it brought to my house. I trusted the guy that ive known forever that it was a good car. Anyway, the mechanics I have used all certified are at a loss.
Could this be a case of the wrong head put on it before I got it since it isn't the original head? Its NOT losing water anywhere, the oil is very good (NOT MIXED at all) Could putting the wrong head on this block and it not matching up with the computer make it run hot?
How about the water pump? Is there an easy way to tell if its good without spending hours getting to it to visually inspect it?
Im about to scrap it out cause Im tired of trying to figure out what it is. ANYBODY got any advice? help?

When thermostat was replaced, did you thoroughly bleed air from system. I've seen similar performance due to trapped air.

A faulty thermostat is also possible even though it's new. Suggest removing thermostat and see if problem is corrected. Replace w/ OEM part if bad thermostat.

These symptoms are also consistent w/ head gasket allow combustion gas into coolant system. A compression test on all cylinders and chemical test of coolant are good ways to rule out head gasket. See videos by Schrodingers Box on youtube on head gasket testing.

Is car actually overheating? Is it possible that temp gauge is inaccurate; either faulty gauge or temp sensor?

I don't know if wrong head would cause these symptoms.

good luck

Thanks for the reply. What is OEM? I bought this thermostat at Autozone so not really sure. If the thermostat is IN or OUT it still runs too hot. I am going to watch those videos if I can find them that you suggest after posting this. When you ask if the car is actually overheating....when I pulled over after the needle got almost to the red, you could hear it boiling loudly, smelled hot and after about 5 minutes I took the radiator cap off and it the water came spraying out fast and hot. Does that mean my guage could be faulty or temp sensor faulty? or does that sound right? The mechanic says he simply does not KNOW what is wrong with it and he is ASE certified. He just says "its gotta be inside the engine" recommends to put a whole new motor in BUT this just does NOT sound right to me. ANy other help you can offer?

OEM means original equipment manufacturer. So TexasHonda is asking if you bought the Honda thermostat. Honda technicians on here suggest to use a Honda thermostat, because it opens at the proper temperature. The autozone thermostat is not OEM and called an aftermarket part.

Pick up a thermostat at your local Honda dealership. It will cost around $25. The pin/hole on the rim of the thermostat should be installed pointing up.

The overheating issue may also be due to a failed headgasket, faulty radiator cap, etc.

See this link to learn more about overheating symptoms:
Overheating: Symptoms and causes

its your temp sensor i had same problem

There's different temperature sensors, but not a bad idea to check them out.

But just because zepljak18's was caused by a bad sensor, that's not the only possibility. Even a faulty gauge reading can be caused by wiring problems rather than a bad sensor.