4.0 cherokee sport, overheats when pulling a trailer. Has a new pump and radiator. I wired the aux fan to a switch. Had a mechanic do a test to check for ,C02? in coolant while running, but was negative. Could a crack in head cause problem only under load. I don't think it is using any coolant under normal conditions. Would like to drive it to VA, but don't trust it for the mts.

 

check your clutch fan. when hot and engine off, fan should be hard to spin by hand.

and maybe add a tranny cooler.

 

I will check the fan clutch tonight. I added a tran cooler a couple of years ago. What about the after market electric fans to replace the clutch and aux fan? Thanks

 

Well the electric fans will def free up some unused power. You'll notice a little more power not using a clutch fan. Maybe improvement in mileage also. Yes electric fans will also cool your motor better also. I do not personally think a cracked head would make it overheat under pressure. You'd be having more problems than overheating if you had a cracked head. Loss of coolant, mixed fluids etc.

 

I'm not convinced by these arguements for an electric fan, that fan has to be powered somehow and the only place that power comes is from the engine. Whether the fan is driven directly or via the alternator/battery you've still got to burn gas to do it.

I'm with you on the cracked head though, if it was bad enough to affect cooling there would be other symptoms.

 

Yes well you need to be convinced. Think about it. The fan is driven by your pulley system. It takes a lot to turn that fan. Therefore decreasing power, mileage etc. Now electric fans take next to no power to run and only come on at CERTAIN moments. The fan on the motor is constantly spinning. The elvtric fans put no stress on your vehicle what so ever where as a clutch fan has many downfalls. Proven fact.

 

^jarrett is correct.

here's a link...

http://www.go.jeep-xj.info/HowtoTaurusFanInstall1.htm

 

So, I can get more power out of the engine, and possibly correct the overheating problem. Seems like the route I should take. I don't have any water in the oil, and it never shows any problems under normal driving. I overheated last night pulling a small trailer and it was 30 degrees outside. Does this sound right? and can anyone recommend a fan to replace with?
Thanks

 

if you're into doing a bit of work, the link above explains it all.

or you can go out and purchase a flex a lite. i think you want a #110. but they're expensive compared to a junk yard taurus fan. $250.00 vs. about $30.00

 

I don't see why you don't get another aux fan and hard wire on up to run when your stat tells it to and then route your other that's on the truck to a switch also that way if you need it while not using ac you can still flip it on allowing your vehicle to cool down a little more under load. Just a suggestion. You can pick up an extra aux fan for like 15-20 bucks at a yard from there on it's all you better just be a wiring guru lol

 

I checked the fan clutch as soon as my son drove in. He popped the hood and the fan was still spinning after the engine was off. It stiffened a little bit after the engine cooled . That's not right, right? Bad fan clutch? Thanks for the fan ideas. I can save some money if this is indeed the culprit.

 

my 95 was running fine until i got on some serious hills like the cajon pass in cali. I changed the thermostate and that was the problem. 10 bucks at autozone and some blue rtv.

 

What's your anifreeze mixture at? If it's pure, it won't cool the engine properly.

 

Its not pure. But I dont know the ratio. After reading some suggestions, I think I am going to start at the beginning, new 16# cap, 195 stat, flush and fill with 50/50 mix of water and anti freeze/coolant. I still think I have a bad fan clutch, I like the idea of electric fans, so I will go that route. Betwwen all this I hope to have fixed the problem. Thanks all.

 

i think there's something up with your clutch fan.

grab one from a wrecker or someone that has a spare. at least to rule that out. then go for an electric conversion. but you will need to wire in a relay and inline fuse to the switch. just like wiring up aux lights.

you could just use another stock xj fan (one with the curved blades, older ones like renix are straight blade and weaker), but i would just grab a taurus fan and go that route. then you've got different speeds and like 4000 cfm.