8G: Engine Overheating during Idle because fan won't turn on (explained)
OP Notes: On my other job I repair HMNVEEs (Military "Hummers") and we usual go through this same problem mainly because the PCM relay box wears out. Because I starting to see many threads on this forum and many just scuff them off by saying "Hey go change the thermostat". This isn't a Nancy Drew mystery novel or some lost Ancient crystal skull alien bs. Most of them already changed their thermostat and the coolant flushed but still having this problem I felt obligated to make a thread out of this....
I'll use this as a questionare:
Quote:
Originally Posted by
Zero_4073
Hey guys. Haven't been on here in awhile. Anyway, my 8g 4cyl overheats while idling for a couple of minutes. If I'm in a drivethru, I have to turn on the heat and the temp goes down. Not too fun in the summer.
I've had this problem for years, and it's getting worse. I still had it after waterpump replacement, thermo replaced, and fluid flush.
Anyone else have this problem? Is there an Eclipse performance radiator that will fit?
Thanks
Good question, now multiply that by 100 people and you get a serious problem. I went to a local Mitsu dealership and there were 7 Galants/Eclipse of the same gen sitting on standby getting this problem sorted out. I will bet clams even the dealership cannot figure out the problem (like they did with mine a few years ago). I can only imagine how many more cars are awaiting repairs or getting a 'for sale' sign because they couldn't solve it. And what's worse, isn't keeping your engine really hot for an extended period of time may lead to a blown head gasket?
The answer(s) are quite simple really.
If you have the Haynes Repair Manual with you (can purchase one at the local auto part store or online), flip through Chapter 3 on section 3-3: Thermostat, 3-4: Engine cooling fans ( Cooling, heating, and air conditioning systems) and Chapter 6 on 6-6: ECT & 6-19: PCM (emission and engine control system)
http://images.solidcactus.com/autobarn/hay68035.jpg
Because of copyright laws and whatnot, I cannot quote what's on this book but you might want to purchase one because it has really cool pictures in them (if you are into that sort of thing)
Basically, here are the components that are involved this overheating issue (in order):
1. Coolant System & Thermostat
2. Engine Coolant Temp Sensor (ECT Sensor)
3. Power Control Modual Box (PCM Box located behind glove box)
4. Fuse Relay (in fuse box)
5. Fan motor assembly
The majority here will see a problem with the idler fan not operating rather than the A/C fan kicking in so you you want to refer items 1, 2, 3.
Refer to items 4 & 5 if A/C comes on but the fan doesn't kick in.
I recommend getting a hold of this book, read it's contents, grab a friend, and work on this problem. According to my experience, the only real challenge is removing the thermostat and coolant (which are explained in the book) and the rest are unscrewing, unbolting, and unclipping stuff.
If anybody wants to add stuff like step by step procedures (in your own words) feel free to do so on this thread.