Engine overheating when turning AC on

[TrexMex]

Well, hot season is finally here and I finally needed to turn the AC on, just to find out the engine temperature needle started rising as if it was the speedometer what I was watching.

I took a look at the usual, Cooling fluid, Oil, etc and everything is fine.. My guess is the problem will not be that simple (hopefully I'm wrong). I was thinking maybe the thermostat, but the problem is only present when the AC is on. I also noticed the engine whining a lot more...

I would appreciate any input before starting to mess around with this problem. It will make my life much easier since I live in Calexico CA and average temp is 100s.

I guess just rolling down the window is not a quick fix on this one..

Thanks.

 

[TrexMex]

Fan clutch.....

 

[KELLY88]

Sounds like for some odd reason your AC compressor is putting extra added stress to the engine causing it to heat up. Could be the compressor clutch sticking.

 

[Ranger44]

Hmmm...this seems a little weird. When the engine overheats, is the compressor extremly hot? Does the compressor act weird when used?

 

[MAKG]

The fan clutch is ONLY an issue if the observation occurred at idle or very low road speed.

I'd suspect a plugged radiator or faulty thermostat.

When the air conditioner is on, you have a big air heater in front of the radiator.

And Calexico is not a good place for cooling systems. I'd strongly suggest the oversize 4.0L radiator if you can get it to work on your 3.0L (I'd suspect so).

 

[Ranger44]

Aahhh. That makes much sense. Didn't think of that.

 

[TrexMex]

The observation was made when going at low speed indeed. Now, the AC system was serviced in January, changed the Radiator around last september and I installed a stock temp Thermostat (there was none before, seems like previous owner didn't like thermostats) about 3 months ago... I inspected the fan clutch last monday and turned out the thing wasn't working at all (free spinning when engine REALLY hot). I went ahead and changed it but I haven't tested it at Hot conditions like the ones we had this past weekend. I can tell the temp is lower at night/morning now, though...

Thanks for all the input guys, really appreciate it. I'll keep you posted about the engine's behavior as soon as we get another over-100 temp day, which I think will be today... blessed desert... but hey, look ma!! no rust!!

 

[fixizin]

And Calexico is not a good place for cooling systems. I'd strongly suggest the oversize 4.0L radiator if you can get it to work on your 3.0L (I'd suspect so).

The totally LAME Chilton's on CD implies the 3.0 and 4.0 radiators are the same... or at least that they remove/install the same way. What years are they different?

No matter, when my '99 3.0 was young it spent a summer off-roading in the NV Mojave @ 108F, and the next summer in the AZ Sonora @ 118F... 4-Low, A/C on, not even a faint rumor of overheating... (and all of this on the "exploding" Firestone tires... LOL)

Hope my upcoming mega-flush doesn't dislodge something, and give me cooling probs...

 

[fordrngr]

I had an "overheating" problem once. It turned out to be the battery. I don't know why but when I was driving the truck and turned the blower motor on the temp gauge would climb. Then I noticed the fuel gauge was rising as well when I turned the blower motor on so I looked into the electrical side and found the battery to be bad.