PR5 overheating - radiator fans not running

Replacing your thermostat might be your next step.

They're only about 10 bucks, and aren't too hard to install.

Doing a coolant flush is part of regular maintenance anyways and the thermostat can be considered a wear item, so you're not really wasting your time or money by changing both.
 
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Ok, there is a contradiction here. This started out as an overheating/fans not running. Now it is overheating with one fan running. Which is correct? If overheating with fan running could still be a head gasket leak. If coolant overflow is bubbling or smelling antifreeze in the exhaust my bet is the head gasket. A sticky thermostat will cause the coolant to overfill the coolant overflow tank unless the radiator is too low.
 
slvrPR5 said:
While parked, the engine running, and the A/C turned off, only the drivers side fan would run.
Click to expand...

I started up my car and ran it in the driveway to see which fans came on. Only the driver side fan came on until I turned on the AC. So I'm assuming that your car is functioning properly as far as fans go.

If your car is still overheating with that fan running you may have a bad thermostat, a partially plugged radiator, or the dreaded leaking head gasket as mentioned above.
 
So, just now, I was driving my car home for lunch and my temp gauge starts rising...and I can feel that the A/C is not blowing cool at all, though it's been turned on. I switch over to heat, blast the hell out of it and luckily make it home before my temp got in the red. Turned the car off, let it rest for a few minutes, and went to inspect everything...no leaking coolant, no cracks in radiator, overflow tank looks normal...I go and turn the car over again, everything starts up, temp is normal and the fan has kicked on. I turn on the A/C, temp starts rising and the A/C fan DOES NOT click on. Turn the car off. I inspect both fan fuses (30) and they are both fine, but I blow em off anyway and switch them, just for giggles. Turn the car on, and the first fan kicks on as it did before...click the A/C on and the A/C fan turns on this time...temp remains normal.

Left my car at home, didn't wanna risk anything, but surely there is an underlying problem here? Electrical? Wiring? I've posted in the past that the pulley on my alternator (which runs one of the serpentines) has been borderline going out, as the belt squeals from time to time, more so when I have a lot of loads turned on in the vehicle (i.e. A/C, headlights, radio) - I've gathered that I basically need to replace the alternator to fix the squeal and get solid tension back in the belt, since it's the alternator pulley that is messing up. Been trying to avoid this repair, as it can get pricey. Is the alternator the culprit here?

Thoughts?
 
I'm pretty sure your fan not turning on and the alternator are two separate issues.
You may have a fan motor that's starting to fail or some sort of bad connection.
If the fan fails to turn on again, test for voltage on the wires feeding it, if you've got 12 volts going in and the fan isn't turning then your fan motor's bad.

Our alternator belts love to squeal... My car does it just about every time I start it... I turn off all electrical loads, wait a few seconds then it stops.
You don't want to over tighten your belt,... That will strain the bearing and cause a failure.
 
marcello.rifco said:
Replace the thermostat. Probably old and rusted.
Click to expand...

^^^ what he said... Seemed to work for the other guy too...

Makes no sense to me how a bad thermostat will stop the fan from working but changing your rad fluid is part of regular maintenance anyway so....
 
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The thermostat will set off a solenoid to switch the fan on when it gets to a certain temperature. It won't cost much to replace and should be done every so often anyway. Most cars I've worked on with overheating issues are because of thermostats being worn out


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Thanks for the replies! I'll get going on replacing the thermostat and flushing the radiator fluid...what's weird is, everything seems to be working fine now. But, that Texas heat is coming and I don't wanna risk anything, so I'll go ahead with these repairs.

@pcb - thanks for your insight into the alternator...about 6 months ago, my car died and the battery was recharged at a Mazda dealership (I have a friend who works there)...he went on to test everything and said the alternator was going out - went to AutoZone and they tested and said everything is all good. Weird. 6 months later, and besides the occasional squeal, everything has been fine. Hoping it holds out for a bit longer!
 
Forgot to ask, will there be a few gaskets that I should replace while replacing the thermostat? I literally just changed the thermostat on my girlfriend's Hyundai Elantra last weekend and replaced 2 gaskets in the process...
 
The thermostat will have a new gasket on it, you won't need gaskets if you are just doing the Tstat.
 
New thermostat on the way...basically, take the rad cap off, rad plug out, drain, pull thermostat, replace with jiggy (sp?) pin aligned in the housing/gasket (upwards?)...replace in reverse order...flush rad with water until clear...re-fill rad with 50/50 coolant/water mix, run idle for 10 minutes or so with rad cap off, turn off, check levels, adjust, run at 2kRPM and 3kRPM intervals with cap off to get out air? Or, what's the best way to run the air out of the system after the new Tstat is in?
 
mattzerstoren said:
New thermostat on the way...basically, take the rad cap off, rad plug out, drain, pull thermostat, replace with jiggy (sp?) pin aligned in the housing/gasket (upwards?)...replace in reverse order...flush rad with water until clear...re-fill rad with 50/50 coolant/water mix, run idle for 10 minutes or so with rad cap off, turn off, check levels, adjust, run at 2kRPM and 3kRPM intervals with cap off to get out air? Or, what's the best way to run the air out of the system after the new Tstat is in?
Click to expand...

Take it for a drive, make sure the heater is working, park it and let it cool, then top off the radiator and reservoir. Continue to check a couple more times after driving it a few times.
 
Hey y'all, changed the thermostat and everything is back to normal, if not better! The car feels like it's driving smoother and the A/C was ICE cold.

Repair took maybe 30 minutes front to back...I really took my time. Took off the air flow thingy on top of radiator (2 10mm nuts), drained the radiator, took off the thermostat housing (2 12mm bolts) and fluid went everywhere haha...whoopsie. I can confirm that my new thermostat came with the gasket already on it, simply put it in the housing with the little bleeder/bead thing in the correct orientation, assembled in reverse order, refilled the rad/overflow and ran the car for a good bit to get air out...and all is well!

Thanks for everyone's input!
 
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