silver99accord

I have a 99 honda accord LX that is over heating when idling. The fans kick on when i turn my heater on full blast after the temperature needle rises well over have the normal temp. I start getting water vapors under the hood and that's when i have to turn on my heater. I've replaced the thermostat once but not sure if that could be the problem again. The car will not over heat while driving. I am experiencing another problem with the car shutting down but i suspect it's an alternator problem which might not anything to do with my over heating problem, i have about 135k miles on it and have not had many issues with it. Any help would be greatly appreciated.

Thanks in advance...

TejasNW

If the car runs fine and temps stay in normal range when you are driving, then you know a few things. Water is circulating through the system and the radiator is doing its job. If you are only experiencing temperature climb when idling, then the first place to look would be the two electric fans behind the radiator. You say these come on when (as in not before) you engage the blower motor for the cabin heater? These should come on anytime the radiator exceeds the threshold for the sensor, regardless of anything else. That is a red flag.

You get water vapor under the hood at idle. Can you narrow down where it is coming from? Front of engine, back of engine, driver's side, passenger side? You say you replaced the thermostat. A new part could be bad, however I would first check the housing it sits in. Did it get cocked funny on installation? Did you use a new gasket? Did you put any RTV or sealant on it? In moving all that around, did a old house spring a leak?

You have a leak somewhere. Start by running that down. The first place to inspect is the area around the thermostat and any and all hoses that run in that area. If you find nothing, pull the thermostat and seal it all back up. If it stabilizes (should be lower temp than normal) then you have found an issue. New thermo stuck closed. Unlikely, but you can then eliminate that variable. It is not a good idea to leave it out other than for testing. There are other systems in the car that need that thermo to do their job, so after you determine the problem don't forget to put it back in the housing.

If the vapor is coming from the driver's side of the car, then I would suspect the water pump going bad. It is 'internal' under the timing belt cover near the front left wheel. It could be that you are not getting enough water moving at idle, due to worn impellers.

Lastly, check your fans. They should come on anytime the radiator is hot, even with the keys off and out of the ignition.

motegicivic

When idleing the rad fan should come on when it hits a certain temp just about 200 degrees or so, if your car is like a civic, should be a switch on the thermostat housing, unplug it, take a paperclip bend it like a "U" put each in the 2 holes of the plug, turn the car to the number 2 position, see if the fan comes on.

supermoto

My car overheats sometimes while idle or standing still. I googled the issue and found that it could be the condensor fan. My 99' has two fans, one on the drivers side and one on the passengers side. The condensor fan is the one on the passenger side. I swapped or crossed my outlet plugs to test both my fans and outlets. Both outlets and the drivers side fan were fine, however, my condensor fan is not working. I ordered an aftermarket condensor fan, complete with motor online. My cost was $61.00 shipped.

thisdamnhonda

im having the same problem with my 99 civic

supermoto

New condensor installed, but old overheating problem still exists. Nothing lost though, cos' the old condensor fan motor wasn't working. It works now. Also, another upside is that the engine isn't really overheating. Matter of fact, it never has overheated. A closer look lately reveals that it's just the stupid guage in the dash that's bouncing all over the place. I mean, since the beginning of this issue, which has been a year ago now, the engine has always operated at or below 200 DEGREES, so I don't know what this foolish guage is screaming about. Going to troubleshoot the guage cluster this week. Will follow up on that as well.

silver99accord

After dealing with this issue for some time, my radiator cracked. I guess there was too much pressure in and it just gave. I had the top cover on the radiator replaced at a shop, when finished the tech there advised me that the fans worked but they weren't turning on automatically. He told me I could either have a bad temp switch or a bad sensor. After i replaced the switch I still had no fans coming on. I called in a mechanic who determined the sensor was bad. Upon replacing it, he broke it when he over tightened it in the head. While trying to remove the broken sensor the extractor bit also broke, his safest solution to the problem was removing the head and having a machine shop remove the bit and broken sensor. He didn't want to risk damaging my heads. Since he had the head off I asked him to go ahead and replace the timing belt and water pump. After a looooong week, he said the car was finished but now the RPM's go up and down by themselves and temp goes up. He suggested that there might be an air bubble in the cooling system. I tried bleeding the cooling system and still no solution to my problem. HELP!!!

AccidentproWn

Does it always do it or only when the car is cold? If it does it only cold I would suspect you're not burping the system properly. if it always does its probably a vacuum leak.

silver99accord

How would you suggest I burp the system? It does it after i start the car up and it runs for about a minute or two. I step on the gas and it starts dropping and climbing over and over. Temp needle also goes up.

AccidentproWn

The way I would do it is to have the front of the car slightly jacked up, remove radiator cap, turn heater on full blast, and turn the car on. Then you keep the radiator topped off while waiting for the car to reach operating temp to insure the thermostat has opened. You can stop once you're sure there's no one air bubble coming up anymore.

The service manual tell you to do it different. I believe there a bleeding nipple on the thermostat housing that you connect a hose to.

If that doesn't work try this thread.
https://honda-tech.com/forums/honda-accord-1990-2002-2/cleaning-iacv-fitv-tb-1844067/

VeeSykkz

I have a 95 Prelude H22a1. I had the same problem with fans not coming on, in my case it was the fan RELAY. I simply grounded it to run constantly. Never had a problem after.

jdmcertified909

i hope your not suggesting for him to do this. if you are why are you suggesting for him to do some half as ****. it has a relay for a reason right? so why are you putting a straight ground to it? why dont you just eliminate the ecu fuse and jump it with a wire. so when theres a short the ecu will fry. sounds good right?

Lost Again

So he replaced the switch in the head? Why not the one on the t-stat housing that actually controls the fans......

ajerman

That's a ridiculously dumb comment. Bypassing the fan relay isn't uncommon in the slightest. Some people prefer to put a switch on their electric fan and run it themselves. You act like a relay is an integral part of the engine that's going to cause the entire engine to blow without it. All it does is turn the fan on and off. The worst case scenario is that your fans might get a little excessive use rather than just running when needed and die faster.

Granted, replacing a relay that probably only costs a few bucks would seem to be a better idea, there's nothing wrong at all with the suggestion. Just make sure it's on either a switched power source so it only comes on when the car is on, or put a switch inside to control it yourself (just don't forget it).

Lost Again

I'm not even sure where to go with this........

VeeSykkz

That is exactly why I did NOT use a manual switch. I live in hot *** Florida. The car has seen LOTS of abuse and even tho it has never overheated except for this bad relay, I like the idea of the fan always running. Keeps a hard working and always wide open engine cooler....I'm not stupid. not bypassing safety circuits, its GOOD to have a cooler engine. When I shut it down so does the fan. Cant leave on what has no switch.

jdmcertified909

well better hope your car doesnt over heat. thats y the fan relay is needed. when you turn off your car the relay is a timer its self as well and keeps the fans on when you remove the key to cool down the extreme hot coolant then turns off when its cool. but if you want to bypass it go ahead. your risking blowing your head gasket much faster by not replacing the fan relay/timer

jdmcertified909

you sir are just out of this world. do you realize that the fan relay/timer helps the car ALOT? the fan/timer keeps the fans running after you remove the key from the ignition if the coolant is to hot. if you bypass it and turn off your fans when you leave the car your risking blowing a head gasket due to the fans not cooling the system down when the car is off. and especially with hot coolant that is just sitting and not circulating making the coolant even that much hotter? im sorry i just dont like doing jobs half assed.

kittchong

my accord 92 overheating simplely the rad cap gasket broken