Rep Power: 332

I've recently started having problems with my cooling system on my civic. When driving whether highway or in town there is no problem but as soon as the car is sitting still it heats up rather quickly. My radiator fans are part of the problem as they are not kicking on, but what could be causing this? If I turn on the A/C the fans kick on but the engine doesn't cool as much as it should. My coolant level is ok, so what else could be causing this? I'm thinking about installing a switch for the fans to see if that will help by turning them on manually.

Also, I've talked to a few people about this and they reccomend a thermostat from an 6th gen SI, for my LX. If it's a direct fit, it should cause the car to run cooler than it does now, which would definetly be a good thing.

Also I've been told the temp sending unit might be bad, so that is another possibility of things to replace.

Has anyone else had this problem and if so what did you do to fix it? It's just at idle sitting still that this problem is happening.

Thanks

 
Rep Power: 0

1) Try a Radiator Flush

2) Replace Thermostat

The gauge should never go over the HALF way mark.

 
Rep Power: 302

Fan switch, fan relay, fan fuse.... Since it works OK on AC, there's nothing wrong with either the radiator or the fans. Sounds like a sensor. Check the wires under the hood, and the engine temp sensor. Check the relay in the fuse box. It's going to be something stupid.

 
Rep Power: 0

...also check if head gasket is blown.

 
Rep Power: 302

Does anybody actually READ the original post? I don't mean to rag, but a bad head gasket does not stop the cooling fans. I must be getting old. Come on, people.... THINK!
But then again, I've pretty much heard it all in 20 years of fixing cars.

 
Rep Power: 302

Ok... looked in the book real quick. Check the radiator fan switch on the engine. It's on the left side, near the thermostat. Unplug the connector and turn on the ignition. Then jumper the connector (not the switch). If the fans come on, the sensor is bad.

If BOTH fans run with the AC on, everything else, including the relays and fuses are fine.
If only ONE fan runs with the AC on, check no.4 fuse (20 amp) and radiator fan relay.

The ecu itself does not control the fan, so it's easy to fix.

Oh yeah... make sure the PLUG is still on the fan temp. switch.

 
Rep Power: 380

Um, car repair rule #1... Change/fix the cheepest part first. So, since your fans are electrical, and they arnt turning on.... the first thing I would do is check the fuses.

 
Rep Power: 0

This possibility has already been eliminated because the fan works with the a/c on. My vote is the temperature sensor as stated above.

 
Rep Power: 362

headgasket. My friend Josh (aka drivetofast) and myself have had this problem for a while and when we pulled off our heads, we immediately noticed the headgasket was blown (mine was blown in 2 places).

In a nutshell: my head got blown by moving too fast and too hard

 
Rep Power: 295

wow, i don't know anyone that pushes their stock civic motor as hard and often as i do

no problem with my coolant ever. i just add water when the tank is below max and i have WATER WETTER

honda radiator are suppose to be every reliable

 
Rep Power: 812

It was hot today with the fans going, but my car almost stalled when taking off from a light. It's an auto, so this is hard to believe. Then it started driving really crappy until I got home. I opened the hood and the stock intake was so hot it could burn my hand. I don't know what happened, but I think it's just too hot. The air coming into the engine is so hot that there's not enough oxygen to run the reaction.

 
Rep Power: 0

Carefully feel your upper radiator hose. It should be hot. If not, then your thermostat has failed.

 
Rep Power: 812

Well it is hot, so I don't know. I heard a clunk or something when I stepped the gas, and it took a second for the car to move. Then after that when I was flooring it, the car would really lag up the rpms. I hope it's just the heat and humidity.

 
Rep Power: 295

WHAT ARE YOU TALKING ABOUT??? Are you talking about the combustion cycle?? Are u saying that the air is so hot there there is no combustion???

As long as you are getting air into the engine, you are getting in oxygen. The reason why colder air makes more energy than hot air is because the energy(i guess this would be a simple term) that you produce during the combustion cycle is greater with cold air.

I'm a Mechanical Engineer. Look up Otto cycle.

You think that the air going into your car is hot?? Imagine my car in the middle of a desert in Southern California. The ambient temperature is about 110F with the temperature on the track being about 130F. Now thats hot.

 
Rep Power: 812

I think I know what happened. The fans might have kicked on right when I stepped on the gas. I drove it around more and it seems fine again. Now it only gets up to 90F around here compared to your temps, but the humidity here is usually above 80%. That makes a huge difference, because of all the water molecules that hinders the combustion reaction.

 
Rep Power: 285

... or its like i said earlier. if your car fouled out copper plugs in a day, and iriduim magically solved the problem, there is a serious issue that was only covered up and not fixed. weather does affect performance.. but not to the extent a lot of people here think that it would cause stalling, rough idle.. etc.

 
Rep Power: 332

Tinman, thanks for all the information, I'll check that switch tomorrow.

I seriously doubt it's the headgasket but that's always a possibility. If it is, at least it's not that hard to fix. (and yes I DO know what I'm talking about, I've done several)

 
Rep Power: 332

Oh yeah, the reason I say it's not the head gasket is there is no white smoke coming out of the tailpipe, and no oil in the coolant.

 
Rep Power: 302

You are correct.

 
Rep Power: 362

what's your point? there was no smoke coming out of my tailpipe (and I have no cat) and there wasn't any oil in my coolant either

if you want me to snap a shot of my head gasket that was blown in two places, I'll be happy to. btw, my car isn't overheating anymore

 
Rep Power: 0

^^^ same here... Changed the head gasket everything went back to normal. Costed me $400 to have it replaced by a mechanic.

 
Rep Power: 812

A cheaper and easier way to see if it's the head gasket would be a compression test. I'm gonna do one soon.

 
Rep Power: 0

Headgasket can leak combustion gases into the water jacket without causing tailpipe smoke and without causing oil in antifreeze and/or antifreeze in oil. This will cause an overheat condition due to improper circulation and contact of coolant with the engine block.

 
Rep Power: 332

I'm suprised to hear that, every car I've ever seen that needed a headgasket showe dat least one of those conditions. I'll do a compression check to make sure that's not my problem.

 
Rep Power: 302

A blown headgasket would not cause your fans to come on, and it would overheat when you are driving fast as well. I'm going by the exact description of the symptom here.
The cooling fans DON'T come on. But they DO work with the AC.
No cooling fans and sitting still or moving slowly will cause overheat. But when you drive faster, enough air is pushed through the radiator and the car cools fine.

Overheating, though, can blow the headgasket.

As to this post:

"Headgasket can leak combustion gases into the water jacket without causing tailpipe smoke and without causing oil in antifreeze and/or antifreeze in oil. This will cause an overheat condition due to improper circulation and contact of coolant with the engine block."

This is true, and used to be very typical in rotary engines as well. Combustion gasses would bubble out of the radiator. Esay way to see if the motor was overheated. Nonetheless, the cooling fans will still come on.

 
Rep Power: 362

^^^ having the same problem with the cooling fans not turning on. Had them with my blown headgasket. However, now that my headgasket has been replaced, my car doesn't overheat anymore even in heavy traffic on a hot day (which happens everyday to me) ... even without the fans turning on.

btw, turning the cooling fans on by using the a/c (even when on HOT) will make your car overheat faster ... but I'm sure u all already knew that

 
Rep Power: 332

not really, turning the a/c on to turn the fans on cools the coolant more than the engine heats up

 
Rep Power: 323

with a headgasket leak, wouldn't there be coolant or oil issues somewhere? Either by leaking onto the ground, coolant in the oil, or oil in the coolant? Or is it simply leaking fumes?

 
Rep Power: 362

that's what my friend said too. Until the needle start shooting up even faster (believe me, I tried this theory many times ... it's not true)

 
Rep Power: 302

^^^ Having driven through the mojave desert with the heater on full blast and all the windows down to nurse my radiator to the nearest town, I can attest to that.
This was in another car, btw. But you DON'T want to add more heat load from the AC.

NO, NO, NO.

Damn, that was a hot trip. Made it, though.