New radiator, hoses, fan motor, thermostat and coolant temp unit. Bottom hose cold, top hose hot. Can idle and temp goes just above half…Start driving, after a few miles temp goes to red, then back down a bit then back up. Open radiator cap no visible “flowing”, however water will burp out every few seconds. Do I go ahead and replace water pump or is this a different issue? Ideas would be fantastic help.
What I’d do w/that situation, I’d remove the thermostat and put in in a pan of hot water on the stove. Use a thermometer to see if it opens at the correct temperature and the full opening dimension as spec’d by Honda.
If it does, make sure you are installing the thermostat correctly, with the correct orientation, and that it is the correct part number for your car. Also make sure you are following the correct cooling system bleeding procedure.
Still overheating? Try replacing the radiator cap.
Next step after that is a cooling system pressure test. Note that this problem can be cause by a head gasket leak, so you might want to ask a shop to test for combustion gasses in the cooling system.
A Honda with those symptoms and that age?
Head gasket!
I bought all the Honda’s I’ve owned with either a blown head gasket or a broken timing belt.
Cheap!
Tester
I am not losing a drop of coolant, oil is clean as well. I could try a pressure test and rule it out I guess.
Just remove the radiator cap when the engine is cold. Start the engine and let it idle and watch the coolant in the radiator.
If bubbles begin to appear in the coolant, that’s an indication of a breached head gasket.
Tester
A head gasket can fail in such a way that it allows exhaust gas into the coolant, but not allow any coolant out of the cooling system. That you aren’t loosing coolant doesn’t imply the head gasket is ok. The bubble test above is a good idea too.
No bubbles at all.
Sometimes you have to bump the rpm well beyond idle rpm before the bubbles will appear. And bubble appearance can be coolant temp related too.
Not saying you have a head gasket problem, but you haven’t disproved that possibility yet.
Okay.
Check for a restricted catalytic converter.
This is an OBDI vehicle. So it doesn’t monitor if the cat is a problem.
Tester
I did get a code 6 on CEL. no other codes.
Did you put the correct coolant temp sensor since there are two?
Suggest to clue us in what a code 6 flags for your Accord. OBD I codes vary car to car and year to year.
Coolant temp
Well, that’s not much help … lol … at least you know your dash coolant temp gauge is consistent with the one the computer uses, that’s something at least. If you are pretty certain it isn’t a head gasket, and a cooling system test confirms it holds pressure ok, and you are certain there’s no air in the system, probably what I’d do next is replace the radiator cap. If that didn’t fix the overheating I’d replace the water pump next. After that I’d replace the radiator again. It may take some trial and error but eventually you’ll find it. BTW, you may serve yourself best by having a pro mechanic with a lot of experience in fixing Accords fix it for you. Best of luck.