Its a 95 Accord with a JDM H22A. The engine overheats everytime i turn the a/c off and let it run for like 30mins. But everything is fine when the a/c is on. Just before the needle hits the middle...when i turn on the a/c everything else drops and cools off.

It just overheats( the needle starts to rise) when im running for the while with the a/c off. What do you guys think of the problem? Im not really techy on engines too. thanks!

 

your primary radiator fan probably isn't working right. the car only overheats if you're sitting still right? when you turn your A/C on a secondary radiator fan comes on and cools stuff down. maybe your primary fan motor is gone, or there's a problem in the wiring.

 

Sounds right to me...

 

It really sounds electrical.


When I turn on the a/c .. its like the rad starts working. Could it be a faulty thermostat? I mean..when the a/c is off and if ileave the engine running, i don't really hear the click from the rad. oh well.

 

Yum Vtec your the man!

 

No, it really sounds THERMAL.

Does it overheat when you're driving (not stuck in traffic) with the A/C OFF? When you're driving, your engine makes way more heat than it does idling. Really. But there's so much air blowing over your radiator that you don't even need the fan running. If its OK like this, then your radiator and thermostat are fine.

Now that leaves your fan switch, relay, wiring, & fan motor. The fan switch should have a setpoint thats a little hotter than your thermostat, so the fan only runs after the coolant gets a little hotter than normal. Turn on the ignition (I don't think the engine has to be actually running). Unplug the fan switch & short the 2 pins together in the wiring plug. If the fan runs, then your wiring & relay & motor are OK. That would narrow it down to a bad fan switch. If that doesn't make the fan run, you gotta figure out why...

Post back & let us know.

 

it is either your fan not coming on or your radiator doesent have enough flow (AKA clogged) and when the other fan comes on it is enough to make it cool down but it can be either

 

Sounds like what happened to me recently, (Non-h22 though) you have two fan switches. One that comes on at 180 degree's and another at a higher temp. The lower temp fan switch went bad on my car, I can't remember but there is some sort of test that you should be able to do to see if you can get the fans to turn on. Does anyone remember how to do that???

My car would start to go above the middle mark when I was stopped in traffic, since there was no airflow ... but would start going back down once the car started to move.

Another question, when you turn your car off .. are your fans still on? They should stay on if your engine is hot ... mine do that in the summer time.


[Modified by Accord_Munch, 6:10 AM 4/3/2003]

 

Hey Jim, I have some more questions for you. I tried what you said about shorting the plug to the sensors out and it worked. However, my cooling fan still does not come on when it gets hot. I have checked the relay and it is fine. I'm really not sure which sensor turns on the cooling fan. There is one on the thermostat housing which I now know turns both fans on together. There is a sensor on the front of the engine that turns on the cooling fan after I shut the car off. So, where is the sensor that turns on the cooling fan when the car is running and the engine gets hot? Also, one more note, when the temperature starts to go up and I rev the engine, the needle drops down again. I changed the thermostat also. Could this be a coolant/water mixture problem?
I would appreciate any help.
thanks

Craig

 

I had same problem i just wired both fans up too ignition so when i start my car both fans come on. Now my car is always running perfect temp.

 

i wired the primary fan to come on with the ignition... temp solution works fine

 

The sensor in the thermostat housing, the one that you jumpered to make the fans run, that's the fan switch. It sounds like you need a new one.

When you're actually driving (not stuck in traffic) does it get too hot? How about when you drive kinda hard?

 

Yeah but Jim is that switch supposed to run the cooling fan at a different time than when the AC is on. It does not get hot while I'm driving only when it's idling.

 

That switch should make the fans run when the AC is turned off. But it's setpoint is higher than the thermostat, so the temperature will get a little higher (but NOT into the red). When the AC is turned on, I think the way they're wired together (fan relay & AC relay) depends on which year/model car you're talking about.

The reason it doesn't get hot while driving is that driving 30 or 40 mph pushes more air than the fans can.

 

Ok Jim, thanks for your help. One last question. I checked the level of coolant and it appeared to be full before. I think I made a mistake there because yesterday I thought I would change out the coolant and replace it and when I drained it, I only got about 2 quarts(maybe) out of the radiator. If my problem is all based upon low coolant level, I sure feel like an idiot. How much coolant should I get out of the radiator? Also, I read in my book that there is a coolant plug on the engine block, can you tell me where that is exactly? I looked up around the oil filter and I couldn't see anything.
thanks for the help.
Craig

 

I HAVE NO DOUBT IT IS THE THERMOSTAT, NOT A SWITCH, now that i have ur attention...same exact thing was happening to my car, it was the thermostat, the sensor/switch that turns on the fans is on the other side of the thermostat, if the thermo is stuck closed, then no coolant can go through the thermostat and run by the sensor/switch and the sensor will not turn the fan on, when the a/c is turned on it automatically turns on both fans

i didnt read everything but im assuming that with the a/c off, while driving above 30ish mph theres no overheating for short distances, its once u come to a stop or uve gone a long distance u start to overheat, change the thermo, easy to do, dont even need a new one, just stick a nut under the point where that rod goes to(when u take it out u'll know what im talking about) and it will keep the thermo open all of the time a just enough, however if u are in a cold climate it will take hella long for ur car to get to norm op temp in which u should get a new thermo and GET A HONDA ONE, other ones arent accurate

 

How'd you check the coolant level? Unless you opened the cap & looked in the radiator, you didn't really check it.

What car, what year, what engine? The block drain plug on my '95 Integra is on the front, under the exhaust manifold at #4. The '98 Accord 4-cyl it's on the back of the block, to the left of the oil filter. Who knows where it is on other engines?

 

I opened the cap and looked in there but it had some at the top. However, after I drained it yesterday I opened the cap again and it still looked the same. So, I was deceived by it and that is probably my problem. My car is a 97 Honda Accord 4 cyl. I assume it's to the left of the oil filter but there is a threaded hole that is empty. Could it be that the plug is supposed to be there and is gone, maybe that's why I'm losing coolant? Also, will the check engine light come on if the coolant gets too low?
thanks Jim.......

 

Sometimes at the radiator cap there's some kinda little shelf, you have to try & look past it, down into the radiator.

If that missing bolt was the coolant drain plug, you'd have probably set the engine on fire by now, so that must be something else... If I remember(lol) the drain bolt was sorta big, had a large opening with a fine thread. You might be looking at an unused mounting hole for something your car didn't come with. Your '97 is 5th-gen & my '98 is 6th-gen, so???

Check=engine light doesn't have any direct way of knowing about low coolant.

 

Great, thanks for all your help. I really do appreciate it!

 

hi Jim, it's me again. Ok I have one last question. Would I know the radiators clogged just by putting coolant in? I mean I only drained about 2 quarts out of it and when I tried to refill it again, I could hardly get the 2 quarts back in. I'm just wondering if this is a sign of a clogged radiator?
thanks

C

 

That may be, but it could be because there's air hanging out in the t-stat housing or the upper hose or heater core or ??.

Crank the temperature dial all the way to HOT.
Crack open the bleeder screw on the t-stat housing (if your '97 has one?)
Squeeze the hoses to push bubbles around & out.
If your garage floor isn't perfectly level you'll have air across the top of the radiator.

Besides, what happened with the block drain (did you find it)? I haven't really paid attention to refilling. I've never put the same coolant back in.

If some of the tubes are completely blocked, that would make sense. There's air below the blockage & those tubes won't fill. But I don't know how much it's SUPPOSED to take if you haven't drained the block.

 

Ok, I found the block drain but I haven't drained it yet. I thought I would figure out the radiator first. I'm not sure if I have a bleeder screw but I will look for it. I will probably pull the radiator and take it to someone who can see if it's clogged. I guess I will do the bleeder thing first and see if that helps it. As always thanks for the suggestions.

 

If you're worried about it, take off the big hoses, get a flashlight & dental mirror & look around in there. If the tubes are plugged, you'll also see lots of crud in the upper & lower tanks.

 

Hello again Jim. Well here's my latest and this should be the end of my pain. I finally took off the radiator and got the hose to it. I stuck the hose in the radiator and flushed it out as hard as I could. Well, it looked to me like everything was working fine but of course I still didn't know for sure. So I took it to someone else and they checked it for free. They told me it was fine. So I thought I would just put it back on the car and forget that the radiator is the problem. Before all this happened I tried to fill the radiator up some more and I couldn't. I only drained about 2 quarts out of it so I thought it was low. When I tried to refill it before, I couldn't get but only 2 quarts in it then. So, now after I flushed it with the hose, it seemed like I could put in about 1 gallon which for me seemed like a lot. So, I got everything back on, started the car, and it hasn't overheated since. I am really thinking I unclogged it by using the hose but maybe that seems wierd. That was the only thing I did and now it doesn't get too hot. GO FIGURE all this but hey that's what happened. I know you have said before that maybe there was air in the system which could have been and I got the air out when I took the radiator off. Anyway sorry for the long explanation but I'm good now. Really wierd but I'm happy. Thanks for all the help. Maybe this will help someone in the future.

see ya

Craig