I've been having a strange overheating problem for about a month now.
I've figured out how to replicated it also. When I turn on the A/C and leave it running for around 10 minutes minimum, the temperature gauge will start to rise and the A/C will begin to cut in and out (go from cold to warm and so on).
Especially if I slow down to side streets, the temp will start to sky rocket. However, if I turn the A/C off, the temp will eventually return to half way (normal position).
I've replaced the thermostat because that's the easiest thing to do, but it hasn't helped anything.
Any ideas on where I should start to troubleshoot this? It's and odd problem, but I guess every problem is odd to me being that I'm not so mechanically inclined.
Process of elimination. Is the radiator cap good and holding pressure? Replace that. Have you ever flushed the radiator? Flush the system, you may have a clogged radiator. Thats what happened on my Ram van. Stayed cool while cruising but temp would rise when going slow. Had to take the radiator to a shop and have it cleaned out. But it was a metal radiator. I think you have to replace the plastic ones.
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Is it an electric fan? Is it coming on when it is supposed too and working properly? Is it a clutch fan, and are the belts in good condition, not glazed or slipping? Is the clutch fan working properly?
Flush the radiator and replace the cap. Did you use an OEM or aftermarket thermostat for the replacement you did? I found the best thermostats were OEM, and not the cheap ones that some parts stores sell. Since you had the problem before the thermostat I think you can safely rule the thermostat out.
With the engine at operating temp and the AC on, see if the electric fan is kicking on. Also take a garden hose and spray out the radiator fins. Go from the engine side of the radiator. A build up of mud/dirt/debris will cut down on airflow.
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I agree with all the comments. I use a power washer, low setting, to clean my radiator in the spring. It blows out the bugs, leaves and other goo that can build-up. I have never had an issue with over heating. The electric fan going bad will cause over heating as a friend of mine found out.
As mentioned before, i'm not so mechanically inclined, but I think I can do the troubleshooting you all have mentioned.
I believe the fan IS kicking on when I start the A/C. It could be that the radiator is clogged so I'll be flushing that out.
I actually work for a company that makes flush machines so we did a full radiator flush on it (which I forgot to mention )
The thermostat I put in it was an aftermarket one that was supposed to be a step above OEM, whatever that means, but I agree, I don't think that's my issue now.
So it looks like I'm going to be doing a few things, checking the electric fan, cleaning out the radiator real good, and I suppose just paying real good attention to what happens when I kick on the A/C.
I'll post back with some results. Again, thanks a lot. I can always count on the Jeep community, haha.
Did you properly bleed the cooling system after you changed the thermostat? Trapped air can cause problems until it finds its way out, and in some rare instances doesn't find its way out unless the system is properly bled.
I'll have to look up some of the parts you're mentioning so I know what to look for.
As far as the bleeding goes. I had one of our techs at the shop do the exchange and I trust him so I believe it was done correctly. The same symptoms are still happening before and after the thermostat exchange anyhow.
It seems that the A/C fan is kicking on when I hit the button to turn it on though.
I'm not sure the fuse would be blow or else it wouldn't be getting cold, then warm then cold again would it?
I had a similar issue on a Dodge Neon 7 years ago. Took it to a shop, they couldn't find anything. Confirmed fan working, flush, thermostat. About 6 months later of driving without A/C on during the day I got a check engine light. Neighbor hooked up his diagnostic tool and was some code that ended up meaning I had to replace a bad or clogged fuel injector. May also want to change your spark plugs and see if there is any noticeable difference on any of them like running lean.(chalky white colored) Maybe someone knows of a surefire way to test for these things?
I feel so bad for putting my radiator through that. It must have been like that for months... Ugh, talk about feeling like an idiot.
I'm not even that mechanical and that just seems like an obvious thing to check out first.
So far so good though, A/C is staying on blast and no signs of overheating yet. I might giving a few more once overs just to be sure all the dirt is out of it.
Now i have a lot of making up to do with my Jeep...