I am having problems with my heating/cooling system. I replaced the radiator, upper and lower hoses, coolant reservoir/overflow tank, thermostat (twice!), coolant temperature sensor and thermo fan motor sensor. AND MY CAR STILL OVERHEATS after driving for ten minutes or so. What usually happens is my thread top pops off of the coolant reservoir/overflow tank. That is a lot of pressure build up. I also noticed that after driving for miles the lower hose is still cold. I though that meant thermostat problem but I replaced that twice properly with a mechanic buddy. He is now suspecting that it might be a problem with the water pump. I have 220,000 + miles on the 2001 Civic EX. I replaced the engine and so the engine has 180,000 miles. He says I should change my timing belt as well soon.

Does anyone also know about an air bag recall for my '01 Civic EX? I got a letter in the mail about it and my SRS light is on. Thanks.

 

what type of engine did you replace your old engine with?

 

Same type. V-TECH 1.7 L (SOHC)

 

I'd be thinking blown head gasket. See if air / coolant blows out when you rev the engine (cold) with the radiator cap off. This gas pressure buildup will displace coolant out of the engine so it can't flow, thus the radiator stays cold and the engine overheats.

 

My car cooled down overnight and I just went out and tried what you said. I opened the radiator cap and topped off the fluid. Took about half a cup of fluid to top it off. Then I ran the car and revved it from inside the hood by pulling on the throttle and every time I did that bubbles and fluid flew up from the open cap. But I thought that is normal when you rev the engine because the force of the fluid pumping? No?

 

That is not normal. There would be no fluid pumping through the radiator with the engine cold because the thermostat is closed. If you want to be absolutely sure with a more sensitive test, take the hose out of the reservoir and put the end in a clear container of water. Leave the radiator cap off but hold your hand over the radiator opening (entire system COLD so you don't burn yourself). If bubbles come out of the end of the hose, more when you rev the engine, that is gas from the cylinders. It can't be because of trapped air or flow.

 

How do you find out the difference between a blown head gasket and a cracked cylinder head? I noticed that replacing a blown head gasket is not too costly to by yourself, but costly if you take it to a repair shop. What about the cylinder head? Is that costly to do yourself or does that mean you just need a new engine at that point? I notice I should also change the timing belt and water pump and some other hardware at that point. Thanks for the input so far.

 

Take the head off and find where the gasket is blown. Inspect the head and block for flatness and visible cracks. The head can be re-machined flat but if the block is no longer flat, the engine is probably too far gone from repeated overheating. If everything looks OK reassemble with a new gasket and test.

 

Thanks for all this advise. I can tell you are correct. It is a bit chilly here in Northern NY so I will wait for a good day and inspect the head. I have never done this before but have one of those Haynes book and have replace my crankshaft sensor and other minor repair jobs. If you have any suggestions and things I should be aware of before I do this then please let me know as well.

You say that the head can be easily machined down. If this is the case then do I send it out to a store to exchange for one they machined down or do I take mine somewhere to do that? Also, where can I buy one of those combustion leaker kits or do I not need to get one now because every time I rev the engine when it's COLD I see bubbles and displaced fluid?

 

YouTube - Fixing Tough Head Gasket Leaks

The guy in this clip shows Steel Seal. Should I try that first?