YJ overheating...need some input!!

JK:CRAWLER

New Member
Joined
Aug 2, 2008
Location
Mint Hill
Got a 1994 YJ...I-6, auto... around town it runs ok, an average temp. of 210....as soon as we hit the highway speeds (steady 55 mph) it wants to climb from 210 (halfway mark) to about 230-240 (3/4 mark)....it's still all factory on the engine....


....we've flushed it, used water wetter, flushed it some more, changed the thermostat, flushed it again, changed the pressure cap, changed the water pump......pretty much everything short of getting a bigger heavy duty radiator......

so that's my predicament let me know your suggestions!

oh yea here's the Jeep.....by the way it was heating up before the lift tires and axle

ai150.photobucket.com_albums_s107_fallenangel1006_r.jpg
 
does it have the shroud still on it?

what about the fan clutch, no mention of you checking it

thats about the only 2 things left to check that i can think of. hope this helps

(after looking at the pic a second time, was the winch on it before the lift and tires? or was it all done at once? after the intial winch install, did you notice this difference?)
 
Stop by a garage and have them put a laser gun thermometer on it to make sure your temp gauge is reading the actual engine/rad temp. THEN start looking for issues.
 
Add a few more items up front that will block air flow. Seriously you need a GOOD (new) radiator. You've made the jeeps poor arodynamics even worse with all the stuff up front.

I run 180 all day long on the trail with a full size rad. but mine still slides up to 195 when i get over 65 for any length of time..
 
I'll assume you have no overdrive, so at highway speeds you are pulling alot more rpm which equals higher temp, put a cheapo manual gauge on it to see if you get the same reading as the factory gauge, if you do not want to get another radiator you can always try hooking up an auxillary electric fan to the front of the radiator. x2 on fan clutch check it as well
 
We put a new BIGGER radiator on it and hopefully we'll see a difference....it was over heating on the way home from buying it, bone stock.....thanks for all the suggestions....I'll post again with results from the new radiator!
 
Good luck. However Jeeps are notorious for gauge issues. Did you have any indications of overheating beside the high temp reading on the gauge? Did it boil over or anything? I would have verified the actual engine temp before putting in a new rad unless I had physical indications of overheating such as boil over, leaking, odor,etc. Just my .02
 
I firmly agree with all the advice given thus far. That said, this happened to me back in the day. I had a 1970 Plymouth Duster. I swapped in a 318 small block to replace the tired slant sicks. It ran really hot boiling over occasionally. All my friends kept saying the 6 cyl rad wasn't big enough. Being a Mopar man I knew they were wrong, no difference btw. 6 & 8 cyl. rads. One day I noticed a freeze plug leaking. Went to pep boys & got the kit. After yanking the motor & old plugs, My Mechanic neighbor came by & said to flush the water jacket with a garden hose & a coat hanger while I was in there. Trusting his vast mechanical knowledge, I did what he said. Out came a ton of rusty metal shavings. I'm not talking about grinding dust. This looked like Brillo pads! he said it was the milling crap from when they originally machined the block. He said this is a common thing in older Detroit iron. Use this info as a last resort, But if all else fails you have nothing to lose but time. Freeze plugs tend to rust out anyway.
 
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