Hello all, I have a 95 that has been overheating for about 3 years now. We have spent $2000 on mechanics trying to fix it with no luck. Here's what's been done to the car so far:

The following parts have all been replaced with new ones: Radiator, Radiator Cap, Thermostat, A/C Heater Blower Motor, Fan Motor, Fan, All Hoses, Anti-freeze(multiple times).

The coolant has been bled and flushed several times, all electrical systems related to cooling have been replaced, there was an intake vacuum leak which was repaired, and the on board computer has been reset numerous times.

After reading a few other threads on this forum about similar issues I have bypassed the thermal switch with a jumper so the fan is running all the time. This helped slightly, but the car is still overheating. It seems to be running cool the majority of the time, and then seemingly out of nowhere the temp gauge will shoot way up to the red. It used to take a long time to go back down but now with the fan always on it takes only a few minutes to cool back down. My questions are these:

1) What would cause the temperature to suddenly shoot up on its own? I have tested several theories including revving the engine or otherwise just driving like an idiot and none of these have an effect. I'll be driving 60mph on the highway for 10 minutes with the temp gauge floating around the mid point and out of nowhere it shoots way up.

2) If the fan is running 100% all the time and the engine is still overheating, could this be a faulty temperature gauge(it's not really overheating)? It's a brand new radiator and all related components are brand new. Obviously the car feels hot to me when the gauge is in the red, but should I try sticking a thermometer on the engine to see if it's really too hot? What is a good operating temperature range and how would I check this?

3) Is there anything else myself and the mechanics are missing? I really hate to spend any more money on this but if we can't fix it we have to sell it.


Thanks for any info.

 

Does the lower radiator hose remain cool when the engine is hot?

Has the cooling system been thoroughly and properly bled?

Has a bad water pump or blown head gasket been discussed?

 

It is slightly cooler than the upper hose is, but it's still pretty warm. If I had to guess I'd say in the 120°-150° F range.

I don't see anything marked as "bled" or "bleeding" in our stack of receipts. I do see "Flush complete cooling system and replace anti-freeze" several times.

Neither of these are marked in receipts, and as my wife is the one who took them to the mechanics over the years(before we were married) I'm not sure if it ever came up. Would these cause the symptoms I have described? The water pump seems like something they would replace before the radiator if it was bad...maybe they overlooked it.

 

If you can get hands on infrared thermo gun, you verify the coolant hoses temp. The temp sender can be faulty and it easy to replace. Hopefully its not a head gasket problem, the Civic engine don't take to kindly to repeated overtemps.

 

My recommendation is that you start by bleeding the cooling system. You can do this yourself.

1) Park the car on an inclined driveway with the front end higher than the rear.

2) Push the dash heater lever/**** to MAX heat.

3) Follow the directions in the diagram below (hint: the bleed bolt is located where the upper radiator hose connects to the engine):

 

Thanks for the info, I'll try bleeding it tomorrow. If that doesn't work I'll be replacing the water pump.

 

Doing a thorough cooling system bleed is definitely worthwhile. But, regarding the water pump, I wouldn't just replace it, unless it's time for a new timing belt. The water pump is often replaced when doing a timing belt job, which costs $350-$550 or so. If when the radiator cap is off, you see coolant moving, then the water pump is likely fine.

My greatest concern is that you have already spent $2K attempting to fix a problem that is not yet resolved. This suggests to me that you should seek out a more reputable mechanic. With that said, if the bleed doesn't work, you may want next to compression test the cylinders to check for a possible blown head gasket. A cylinder leak down test would also be informative. If the head gasket is fine, then I would suggest that you replace the radiator. This is a DIY job that you can do at home (save $$$).