Maybe you all can lend a helping hand. I recently acquired an 86 GT. I seem to be having an overheating issue. I replaced the stat with a 180 degree piece and put on a new radiator cap. That didn't seem to fix the issue as when I run it for more than 20 minutes at highway speeds and park it the radiator starts to steam and overflow the overflow container. The car is 100% stock with no mods and has the factory plastic fan. Could I be looking at a fan clutch problem or even a Water Pump problem? Ideas
Overheating and don't know why
- Thread starter 93-331-29psi
- Start date
mustangsquared
Founding Member
I would flush the coolant system and replace the fluids (since you do not know when done last). I would then "turn the fan". Does it move back and forth easy? Especially when hot. If so then it is a bad fan clutch. Also check to make sure coolant system is holding the PSI (I think 86's are 16 PSI). If all that doesnt fix it then it is probably the pump.
mustangsquared
Founding Member
bln92cpe
New Member
get a flex fan and a fluidyne radiator..Thats what i did and now the fan blows cold air and my hood ramains chill after driving it.
Screw getting a flex fan and the hell with the stock clutch fan. Go to the junkyard and get a taurus electric fan for $25.
I had trouble with overheating when it would idle for more than 10 min.
It would slowly climp to 220-230* until I got moving again.
Now, it will stay at 170* all day long at idle.
If it boils over when you park it, it sounds like you don't have enough anti-freeze to prevent it from boiling over.
My probem was that the stock fan couldn't pull enough air through the radiator at idle....but my GT has a worked 351w though.
I had trouble with overheating when it would idle for more than 10 min.
It would slowly climp to 220-230* until I got moving again.
Now, it will stay at 170* all day long at idle.
If it boils over when you park it, it sounds like you don't have enough anti-freeze to prevent it from boiling over.
My probem was that the stock fan couldn't pull enough air through the radiator at idle....but my GT has a worked 351w though.
Well this is just a daily driver so I am not putting tons of cash into it. I need to get my 93 done. Anyhow I have a 70% antifreeze 30% water mixture. It can sit and idle and not overheat at all, or at least not over the period of an hour, but starting cold a 5 mile drive around the block and she climbs and overflows the overflow tank. I am going to flush it again and replace the water pump and s ee what that does.
If it overheats while driving then it's the radiator. If it overheats while at idle then it's the fan.
Since it doesn't overheat at idle then I doubt it's the water pump.
At this point, I would take the radiator to a shop and have it hot tanked. That will get out anything you might have possibly missed with the flush kit and absolutly rule out a bad radiator.
You don't have a bad head gasket do you? Check the oil dip stick and make sure it's not milky.
Since it doesn't overheat at idle then I doubt it's the water pump.
At this point, I would take the radiator to a shop and have it hot tanked. That will get out anything you might have possibly missed with the flush kit and absolutly rule out a bad radiator.
You don't have a bad head gasket do you? Check the oil dip stick and make sure it's not milky.
Well I think I figured it out. There was an air bubble in the cooling system. I let it run for about 30 minutes with the cap off in the driveway and noticed the fluid level went down. Topped it off with water, put the cap on and gave it hell. No boiling over but the factory gauge runs on the high side of normal. I will have to get an after market gauge on it and see where I am for temperature. Thanks guys
the one thing your overlooking is what caused the airpocket.air pockets don't form for no reason.air has to be entered into the system by someone opening the system up and not properly filling it or you have an internal leak such as a blown headgasket or cracked head or block.if your air pocket comes back in a few days then you better start worrying.
nah, i think D is actually right. the thinking is this:D347643 said:
while driving (normally alikened to being on the highway), the air being forced through the coil from speed (not the fan) cools the radiator. but when stopped, the only means to force air through the coil is the fan.
you are right - it is a little counterintuitive - it seems that the fan spins slow at idle. this is where electrical fans really shine. but a clutch fan will spin enough for an idling motor (that is the way it is engineered - to flow enough CFM's at idle to cool the charge sufficiently in extreme conditions).
once one is travelling at ~25 MPH or so, the fan being on (even a Mark 8) is immaterial - the speed of the air hitting the radiator (or creating the cavity of low pressure behind the radiator, in some cases) is enough to create a nice 'gust' that is much more than what the fan could do.
Just an FYI, I was told by a mechanic once that a good way to see if your fan clutch is on the outs is to have a friend turn the car off when it is at full operating temp. Stand to the side of the car with the hood open and count the number of times the fan spins before stopping. More than 2-3 times, its shot.
Similar threads
