weird overheating - Honda Prelude Forum

bigliegs58 · 06-12-2005, 12:35 AM

I have this really weird overheating problem, i just put a new motor in and it seems to be overheating, but the thing is that when the thermostat opens the fans would turn on, then the temperture gauge would go up one bar, then fan would turn off after like a couple of seconds, but the the gauge is still one bar over, after a few more seconds it would drop down to normal, this is when the car is idleing, and when driving it does the same thing but the bar would stay lit longer then a couple of seconds, i also replace all the old cooling parts (fan swtiches, thermostat, temperture senors)parts for the orginal since i knew those work after i took out the old motor. this problem has been really fustrating since i have bleed the coolant like a 1000 times and the problem doesnt seem to get any better, and i cant figure out way it seems to do this, please help me

Sonik_Fury · 06-12-2005, 01:50 AM

Did you replace the radiator or cap??

bigliegs58 · 06-12-2005, 08:08 AM

no i didnt, and my radiator is in crappy condition, but it seems to be a electrical problem with the fan, not turning on early enough and turn off to early, if it matters, this is a jdm h22 w/ jdm ecu

red92s · 06-12-2005, 08:39 AM

Did you swap over the second ECT sensor?

bigliegs58 · 06-12-2005, 02:49 PM

if thats the sensor thats at the end of the top radiator hose then yes i did swap that

TruNinja619 · 06-12-2005, 10:27 PM

Quote:

Originally Posted by red92s

Did you swap over the second ECT sensor?

you only have 1 ECT sensor.. unless you're talking about the ECT gauge sensor...

or

are you talking about the 2 fan switch sensors?

TruNinja619 · 06-12-2005, 10:29 PM

Quote:

Originally Posted by bigliegs58

if thats the sensor thats at the end of the top radiator hose then yes i did swap that

thats the fan switch sensor B...

don't be fooled to think you have 2 ECT sensors like I did.. lol...

bigliegs58 · 06-13-2005, 04:55 AM

wheres the ect gauge senor located?

TruNinja619 · 06-13-2005, 07:53 AM

Quote:

Originally Posted by bigliegs58

wheres the ect gauge senor located?

if you're looking directly at the ECT sensor... its the sensor at the right of it...

try replacing that first... i'll try takinga picture of it for ya..

trident · 06-13-2005, 11:56 AM

I'm having the same problem. My car overheats, and then both fans turn on. The fans will not remain on after I shut off the car (like Helms says it should). The car does not overheat if my A/C is on. I attribute that to the A/C fan being on, and thus cooling the radiator. I have not tried replacing parts yet. I'm not sure whether or not to replace coolant sensor A or B first (or to just try and test them)

TruNinja619 · 06-13-2005, 01:28 PM

Quote:

Originally Posted by trident

I'm having the same problem. My car overheats, and then both fans turn on. The fans will not remain on after I shut off the car (like Helms says it should). The car does not overheat if my A/C is on. I attribute that to the A/C fan being on, and thus cooling the radiator. I have not tried replacing parts yet. I'm not sure whether or not to replace coolant sensor A or B first (or to just try and test them)

don't be confused like I did for the longest time thinking they were ECT sensors...

they are Fan switch sensors...

you only have one ECT sensor...

trident · 06-13-2005, 02:06 PM

So are you saying that sensors A and B as they are called out by helms detect whether or not my fan is on? If so, why would they be in the coolant stream? If I am not mistaken, these are switches that open and close based on the temperature of the coolant. This would make them temperature switches that are inputs to the fan control module. In this sense, you should be able to determine your coolant temperature by which fans are on. Now, to address my question, which switch would be bad if both fans do turn on, but don't stay on after the engine is turned off? In addition to this, they don't both turn on until the temperature gauge reads that the car is overheating. If the first part of my problem was not occuring, then I would assume that the resistance range on my ECT sensor was bad, and I would just replace that. Since that is not the case, there are only three other places where the system could be failing. That is coolant switch A, coolant switch B and the fan contol module. There is a troubleshooting scheme for the fan control module, but it does not address the symptoms that I am having. Does this all make sense?

bigliegs58 · 06-13-2005, 06:19 PM

Omg Thats my exact problem, Please help us

bigliegs58 · 06-13-2005, 08:59 PM

do u have a jdm motor?

trident · 06-13-2005, 09:13 PM

Yeah, I do have a JDM motor. I'm about 95% sure that the problem is ECT switch A. The radiator fan cannot run unless the condensor fan is running ( they work off the same ground). It can work when the A/C is on because the ground that ECT A makes is being bypassed by using the A/C. When you turn the car off, the A/C turns off, therefore, if ECT A does not close, the radiator fan cannot turn on. This is why both fans turn on for a little while (just to cool the engine down enough) and then they turn right back off. I'm going to buy this switch myself and see if it solves the problem (as I'm nearly sure it will) I'll let you know.

bigliegs58 · 06-13-2005, 09:55 PM

thanks you very much that makes tons of sense.

bigliegs58 · 06-15-2005, 04:50 AM

anyone else have any suggestions

fourthgeneration · 07-05-2005, 06:28 PM

Quote:

Originally Posted by trident

Yeah, I do have a JDM motor. I'm about 95% sure that the problem is ECT switch A. The radiator fan cannot run unless the condensor fan is running ( they work off the same ground). It can work when the A/C is on because the ground that ECT A makes is being bypassed by using the A/C. When you turn the car off, the A/C turns off, therefore, if ECT A does not close, the radiator fan cannot turn on. This is why both fans turn on for a little while (just to cool the engine down enough) and then they turn right back off. I'm going to buy this switch myself and see if it solves the problem (as I'm nearly sure it will) I'll let you know.

did you ever figure this out?

im having similar problems on my h23. slightly different though. at idle my temp starts to crawl up. i let it idle for a while and the fans did come on late, the temp bar goes up to 3/4's and I shut it off. also, the fans do not come on anymore after I shut off the car...

trident · 07-05-2005, 07:16 PM

it'll happen at idle too. It doesn't sound like a different problem. I have to be honest, though, I have not yet had a chance to switch out the temperature switch yet. It's only a $30 dollar part. Anyway, when I get around to it, I'll let you know how it turns out. Also, do you have A/C? If so, turn it on and see if your problem goes away. If so, then I can pretty much guarantee it's temp switch A. Good luck.

fourthgeneration · 07-06-2005, 02:09 AM

Quote:

Originally Posted by trident

it'll happen at idle too. It doesn't sound like a different problem. I have to be honest, though, I have not yet had a chance to switch out the temperature switch yet. It's only a $30 dollar part. Anyway, when I get around to it, I'll let you know how it turns out. Also, do you have A/C? If so, turn it on and see if your problem goes away. If so, then I can pretty much guarantee it's temp switch A. Good luck.

when i tested in my garage i had the a/c on 1/2 way. the temp still went up...