rookcherokee

So recently the heep has been creeping up to 220* while driving for about 30 minutes or so but never really goes further and overheats. Any reason for this to be happening? I just don't want this to cause a problem for me in the future. Anything I can do to not have this happen and the keep the temp down? Any help would be great! Thanks!

kidkodiak

Have you done the normal cooling checks?

Backflush the system and refill it
check your hoses, check for leaks.
You have the Renix engine? Check your overflow container, make sure it doesn't have any holes and that the pressure cap is keeping pressure.
change thermostat?
make sure your electric fan is engaging at 220... that's your AC fan, on the front driver's side of the engine. It should auto-engage at about 220 to add additional cooling.
check your clutch fan, might need replacing.

These are just starter ideas. I spent most of the early part of the summer troubleshooting and fixing my cooling problems on my '90 laredo, so hopefully my lesson's learned will help you a bit

rookcherokee

Thanks for the quick response. Yes I have the Renix engine. Hoses are fine, no leaks. Haven't backflushed it.(Don't really know how) Overflow container is in good condition. What's the best thermostat that I should replace the one I have with? Was also thinking of replacing the fans with a dual electric but not sure of how to do this. Has anyone done this or no of a simple write up for this?

kidkodiak

For the thermostat, I buy it from the dealer. If you look at the oem thermostat next to a, say, Stant... the oem is way beefier. It cost me maybe $10 bucks direct from the dealer, too, so it wasn't expensive.

Have you ever replaced the fan clutch? That might be something to look into... after a while it wears out. Part costs about $60 bucks.

Also, check the AC fan, make sure it's coming on. You might not be having cooling probs, per se... it may be that you're alt. fan isn't turning on at temperature.

EDIT: and you can buy a flush kit for the cooling system, or pay $25 bucks and have a shop do it. They'll flush it all out back to the heater core and clean out the junk.

Radiator looks ok? no pinhole leaks? is it moving fluid through at temperature?

rookcherokee

I think i'm going to upgrade the entire cooling system - thermostat, radiator, hoses, fans, etc. Where should I start? And where are some good places to find these items? Thanks

kidkodiak

That might be kind of expensive... I think I paid about $600 bucks for all my gear for the cooling system redo... parts add up. Maybe start with a couple simple things and run your truck for a bit, see if it's running cooler.

Have the system backflushed and pressure checked first. Plus clean coolant is always a good thing. Replace the thermostat. Make sure hoses are new and in good shape. Run the truck for a bit, see if it's helped.

if not, then it's piecemeal, but I'd start with making sure the electric fan comes on at temperature first. If yes, move to fan clutch. If no, troubleshoot electric/AC fan.

And just work from there. Save you some money. In my case, I had to replace everything... most of it was original stuff in a 20 year old truck... radiator had a leak, pressure bottle got a pinhole leak, had original clutch fan, coolant temp sensor, etc etc... so I did it all at once.

But that's not necessarily what you need to do
I guess I'm a proponent for saving money where you can.

Good luck with this!

xj92

i noticed that my heep was getting hot and the electric fan kept coming on, i looked at my radiator and saw that there were allot mud caked in the front and back of the radiator, i went to a self serve car wash and spent $6 in quarters. that helped allot, my heep still runs hot, but not nearly as bad as it did.

Codycobra84

Mine did the same thing, ended up putting a cooler temp thermostat in it and helped alittle. Got to looking and found that the clutch fan wasn't holding like it should. Pulled the one off of my MJ and put it on it, runs cooler than ever now. May end up putting the OEM temp thermostat back into it in a month or so when the weather starts to change.

-Cody

Firestorm500

If its not blowing coolant out, its not running too hot.

220 degrees is not too bad. The coolant won't start boiling until about 240 or so.

Volcomroofus

I just got my fan clutch in today but havent installed it. The fan turns very slow when I get hot and im talking 260+ It jumps from 210 to 260 in a flash. The electric fan never turns on, on its own. It does however, turn on when I turn the a/c on... Would the fan clutch fix this problem at all, or is the electric fan have nothing to do with the belt driven fan? I know it's sounds stupid and lack of common sense but motors are chinese to me right now..

kidkodiak

Interesting... that's what happened on mine, too. Well, if it turns on when the AC is on, that's good... means the relay and the fan are both working.

In the meanwhile, when the engine starts to get warm, turn on the AC. Just engaging it will kick the fan on and blow more air over the engine. Good thing with replacing the fan clutch too, that'll make a difference.

The Coolant Temperature Sensor tells the electric fan when to engage. It bolts on to your radiator on one side and into a wiring harness on the other. I'd replace it, shouldn't be too expensive to do. You'll probably leak fluid... ( I did mine on a new install radiator, so didn't deal with it) I think you'll need to drain the existing rad first.

I used some plumbers tape on the threads too to make sure it was snug... pry don't have to do that, just throwing it in.

EDIT: And no, to answer your question. The clutch fan has nothing to do with the electric fan.

Volcomroofus

would that sensor not working properly affect why the clutch fan isn't spinning fast enough... Just a thought...?

kidkodiak

Nope, the two have nothing to do with each other. The electric fan is for the AC, but has that coolant temp. sensor that tells it to turn on when it reaches a certain temp, acting as a secondary fan for the jeep. The mechanical clutch fan spins with the engine... but doesn't spin at the right speed (hope I'm saying this right) when it starts to go out, thus decreasing the air flow over the engine.

I'm sure a better techie than me can explain the mechanics of it better... but that's the gist of it

Codycobra84

Basic thing is the fan has a clutch type setup in it allowing the fan to slip, the same why you would slip a clutch to keep from drivetrain shock. If the clutch part of the fan wears out then the fan doesn't come up to speed like it should, like a car with a bad clutch, it slips and is useless. Make any sense? I typed this on my phone so sorry if I misspelled anything.

-Cody

Firestorm500

X2. Your fan clutch is probably bad. Try replacing it.