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Car running hot, help needed.

H8D-XJ

NAXJA Forum User
Location
San
So i went and picked up my XJ yesterday, car runs great an everything. Heres the mod list:

jeep cherokee laredo 4x4 4.0 automatic
4in lift
33in tires
5 jeep rubicon wheels
custom front/rear bumper
tire rack with hi lift and jerry can on back
KC lights on front and 2 accessory lights for night wheeling on back
dana 44 rear with detroit EZ locker in rear
4.10 gears
rear disc brakes
rubicon express drop down brackets with brace for lower radious arms. ( no death wobble )


Only thing is over the altimont pass which is a pretty good climb to 1000 feet from sea level it got really hot. Was sitting right at or below 210 and the more I did the climb the higher it got. It reached all the way to the beginning of the red as I got to the summit then it cooled back down as I coasted down.

He said it has a radiator from a 94 in it and the electric fan is wired to a switch so I had it on the whole time. In traffic or at idle it was fine, stuck right at 210.

 
Heres some pics of the open system conversion, if you guys could look at it and tell me what to fix cuz it looks crazy right now.

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And somebody tell me what the hell is this thing??

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It also looks like he bypassed the clutch on the fan by bolting a bracket straight from the pulley to the fan, is this a bad thing??

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I've fought that problem on mine off and on for years. I would restore the viscous fan myself. No need to rob any power when you don't need it. Mine had a plug radiator originally along with a bunch of little stuff Its surprising how little in the system even on the later years makes a big difference and how hard it can be to get out. I had a hairline crack in my heater control valve that was just dripping and replacing it made a night and day difference. I also have my electrical fan wired to a switch on the dash and just recently added one of those aftermarket thermo fan switches in line as well. That way I have control of the fan manually but don't cook the engine if I forget to turn it on in traffic. Good luck!

BTW: that round bulbous thing is the vaccum resevouir. Keeps your heater and things working under WOT. Normally is mounted in the front bumper but if you swap our bumpers it gets stuffed wherever you can fit it.
 
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It could be that the tranny fluid is heating up the coolant when you are going up a hill. I had this problem with mine. I installed an auxiliary tranny cooler and didn't run the tranny fluid through the radiator any more and it solved that problem. I recommend you thoroughly check out the rest of the cooling system for issues. It seems the previous owner was having problems and rigged the fan to turn at full speed all the time so there's probably problems elsewhere.
 
And somebody tell me what the hell is this thing??

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FYI, a good thing is that the brake booster and master were upgraded. oem booster was a single diaphram and it was upgraded to a dual diaphram. not sure of the year and model(xj or wj) the booster came from though. just wanted to let you know incase you need a new master cylinder in the future
 
If you don't see any leaks and the fluid level is full, check the fan clutch and pull the radiator and have it checked out. If it's fine except when under a good load, I'd think it was either the fan clutch or a partially plugged radiator.
 
Ok, so you just got it.

Now, you get to A**ume that the damn thing has never ever been serviced. Start with a flush of the radiator--not plain water, not the 15 minute kind, get the good stuff you put in and leave for 500 miles kind. Replace the hoses and thermostat--recommend the Stant SuperStat Premium 195 degree. Before and after the flush inspect the weep hole in the water pump, if you see any coolant replace the WP--new, never used. Yes, loose the ghetto fixed blade fan, the viscous fan stops engaging when the temperature of the airflow through the radiator hitting the bi-metal spring is less than 170 degrees and that takes a load off the engine--you can upgrade to the ZJ HD fan clutch from NAPA, part number 272310, $44, direct fit--not the ZJ MAX Cool, it won't fit. Do a poor man's flush on the transmission, Dex III--bad fluid = slippage = heat. Check the radiator, make sure nothing is blocking airflow through the fins and around the tubes. Check the belt, recommend the Goodyear Gatorback, set to 180~200 ft lbs for a new belt.
 
Definitely replace that rigged fan clutch. I would also return the electric fan to its intended mode of operation unless you plan on going in to water with it and have the need to shut it off. Have the radiator checked or cleaned.. but depending on the rad shop pricing in your area it may just be easier/cheaper to replace the rad.

I have no idea what is going on with that open system conversion, but I'm also not familiar with the closed system.
 
One thing I'd take a look at (after looking over the cooling system) is your cat... a good way is to feel the floor board above it while you're having these overheating issues.

I was having a similar issue and mine was clogged shut, caused the Jeep to heat up quite a bit on grades, and cool off almost instantaneously on the downhill.
 
Since the fanclutch has been bodged up to be on permanently ... ( not nescessarily a bad thing depending on your driving requirements ) ... and you have still rising temps underload .....

X 2 on joe_peters comments re: servicing / flushing .... Other likelihood is that a new / reconditioned radiator is required ... as your described symptoms are typical for that problem ....

Gearbox & cat temps as mentioned, also need to be considered ... but its a matter of getting the basics sorted first ... and then look at the non-cooling items, that affect the cooling system.

An over-ride switch for the leccy fan is a good thing .... but a cooling system with a decent radiator (non-genuine) and a decent fanclutch (probably non genuine) ... and a proper 195'f thermostat (non genuine) should avoid the need for it.

BTW .... it is "normal" for an engine to get hotter under load ..... Thats why manufactures should provide a decent cooling system in the first place ... instead of one just suited to their "best for them" testing levels.

Its also a good reason to have a lower, "normal" operation running temp .... so it doesnt get toooooooo hot under heavier, short-term working loads ... when the OE cooling systems are inefficient for all circumstances.
 
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theres absolutely nothing wrong with having ur elec fan on a switch u can turn it on when ever necessary u just gotta always keep an eye on the temp. i actually had to put mine on a switch cuz having it plugged into the system it wouldnt come on no matter the temp
 
theres absolutely nothing wrong with having ur elec fan on a switch u can turn it on when ever necessary u just gotta always keep an eye on the temp. i actually had to put mine on a switch cuz having it plugged into the system it wouldnt come on no matter the temp
True, but it should still be setup to automatically run when the temp gets to the correct temp it is supposed come on at.
 
Thats the beauty of running a bypass but keeping a thermo switch on the electric fan. Got mine from summit for $25. Fully adjustable and came with a probe I panduited to the upper radiator hose. Set it so the fan switches on when the temp just gets above the norm and cuts out 20 degrees below the on point. Switch in the cab lets me shut the fan off for water crossings.
 
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