My accord has been overheating lately - not to the point of smoking, but it gets in the red - but only when at idle, not for very long. If I'm at a string of 10 red lights in a row (10 minutes, tops) it'll be in the red. I initially assumed it had to be the thermostat, so I switched that out about 2 weeks ago. Since doing that, it actually seems to be doing it move often and a bit faster. After turning my car off, the radiator fan runs for (literally) 5 minutes or so, but it sounds like it just kicks on AFTER I turn my car off and possibly it's not running while my car is running?

Obviously I don't know much about cars, but I'm good at fixing things when told what to do. I really don't want to take this to a mechanic and pay him $500 to fix it when I can do it myself but I have no clue what the problem could be. thanks for your help in advance.

 

Do you have enough coolant in there?

Have you flushed it already?

 

Well, first thing is that you need to check if the fan comes on when it is running.
Then, check if enough coolant is in there

When you changed out your thermostat, how much coolant actually escaped? And did you replace it? and with what.

fs

 

I assume I have enough coolant in there. I didn't lose much coolant at all when replacing the t-stat, there was still plenty in the overflow so I didn't add any to it. I will re-check that.

I don't know how to flush the coolant, is that very hard or do you need a machine to do it? That's what I'd like to do as a next step. It has the green coolant in it, rumor has it that i'm supposed to have the red - whatever the hell that means. but i hit a phesant about 4 years ago and had the radiator replaced as it cracked and that's what's been in it ever since.

How do I tell when the fan is supposed to come on?

 

Nevermind flushing the coolant for now. Go for a drive with your car. When the temp guage shows about half way, open the hood, let the car idle and wait for the fan. Now if it goes beyond the halfway mark, and the fan still has not come on, you have a problem in that fan circuit. Be it the switch, open circuit, or whatever...

 

when the car is running and the a/c on,do both fans come on or just one? they both need to be running when it reaches temp.

 

I have a 20 mile drive home from work, I will check it when I get home tonight and see if the fan is running or not. When you say "both fans" - what is the second fan you're referring to?

If it is this circuit for the fan - is that expensive and/or hard to replace? It seems like the fan would be a logical explaination as when I'm idle it overheats, but when i'm driving it cools back down, so the motion of the air going across the hood (as the fan SHOULD do) gets it cool. This makes perfect sense to me, hopefully it's the problem if it's an easy fix!

 

there are 2 cooling fans under your hood if you have a/c,they both should come on if not,tap on the one that is not running and see it it tries to turn,if so, replace it

 

Did you replace the thermostat with a Honda OEM part? Some people on the forums including myself have had problems with non-Honda OEM parts. Bought a brand new Stant thermostat and it only made my overheating problem worst. Also, check your fans, radiator fan and condenser fan relays, and coolant temperature switch A and B. Like you said, when you drive the temperature goes down, so that's good. Doesn't sound like a bad water pump or blockage. Either of these two things would make your car overheat no matter how you drive.

 

so last night i drove the 20 miles home from work, parked, left the car running and popped the hood. the heat gauge was between the red and halfway, closer to halfway. popped the hood and neither fan running. (i dont' use my a/c, i drive with my windows down) turned on the A/C and both fans started running immediately. As soon as I turned off the car, the driver-side fan kicked on while the passenger-side one remained off. Shouldn't the driver-side fan be running while I'm driving if the car is that hot?

I did not replace the t-stat with an OEM part, it was an aftermarket brand, I don't remember what brand. the box was yellow and black stripes. big help i know

 

Coolant temperature switch A is a fan switch that is located on your thermostat housing. This switch will close the circuit and turn on both fans when the coolant passing by it is hot enough. Since your fans aren't coming on while you're driving then they're are several possible problems (given that you can confirm that your fans aren't coming on while you're idling). Open circuit between fan switch and fan, bad fan switch, bad fan, thermostat not allowing enough flow, bad condenser fan relays, and or radiator fan relay. You can test the circuit by unplugging coolant temperature switch A while the engine is running and jumping the circuit. Use a paper clip to do this. If both of your fans come on, then the wiring, fuses, and relays are okay. Do a search on overheating. You will find lots of trouble shooting techniques.

 

I will try to jump the circuit tonight. The only thing that concerns me is the car still overheats even with the A/C running. So although the fans don't run when they need to by the car being hot - even if I force them on (by running the A/C) - it overheats until the car is in motion.

Does this change your response at all?

 

Here's an update for you....

Last night I completed the circuit on the coolant temperature switch a by using a paper clip like dockersguy recommended (with a paper clip). Upon turning the car on both fans started right up, I therefore concluded that (since the fans weren't turning on on their own) that the switch was faulty. I swapped that out and took her for a test drive - the fans now come on when they're supposed to....but it was still overheating while the fans ran....so I let it cool down and this morning before work I woke up and bled the radiator. It didin't take much coolant at all (maybe 6oz) before it came out the bleed hole (if that's what it's called). So then I drove to work...still overheating....but at least the fans work now.

Any further suggestions?

 

replace the thermostat with OEM part from HONDA.

 

Couple suggestions...

Genuine thermostat, like Elvis says. Off-brand sometimes are good, other times...?? Genuine T-stat isn't all that expensive.

Run the car with the heater set to full-hot. Air bubbles can hang out in the heater core. Then bleed it again.

When it's cold, squeeze each radiator hose. You should be able to hear sloshing noises if there's air, & the hoses feel different. You should only hear that funny little pin rattling in the thermostat.

Finally, after ruling out the easy stuff, it's possible that your radiator is plugged with crud. If so, you might need a new radiator.

 

FYI - the day after the next post it stopped overheating. I'm not sure if the radiator flush/bleed just took a day to kick in or what - but I've had this thing in VERY extreme conditions (meaning - about 10 times worse than what it used to take to overheat) about 5 times in the last week and the temp hasn't even gotten near the halfway point. I'm going to proclaim that it was a bad switch a to the fans and air in the system, a combo of problems.

Thanks a million for all your help guys and gals!

 

Ok - it worked perfectly for 2 weeks and now my fan isn't coming on AGAIN!!! I'm going to test the switch again tonight but what could cause a switch to go bad so fast. The absolute SECOND I turn my car off the fan turns on, but it doesn't run when the car is running - it worked perfect for 2 weeks after I did the switch A replacement...


NOTE/EDIT: this was a false alarm, i'm a ******* tool and didn't tighten one of the hoses after switching these parts and all the coolant leaked out -- it's fine now and has been for a LONG time. it was an ID 10 T error.


Modified by fleetmack at 8:55 AM 10/13/2004