Mechanics

OVERHEATING

1989 Jeep Cherokee • 6 cylinder 4WD Manual • 127,000 miles

My jeep cherokee 4.0 6cyl is still overheating after I have replaced the thermostat, water pump, radiator, changed oil, spark plugs, and ive even ran it without a thermostat and it still overheats. It doesnt leak any fluids. Help me please.
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89jeepxj
May 23, 2011.



Are your radiator hoses s. Ucking flat (no anti-collapse spring, some do not have them anymore)

What about your fan clutch, maybe it's messed up, and free-wheeling too much.

The Medic


Tiny
CJ MEDEVAC
May 23, 2011.
The lower radiator hose has a spring. Upper hose gets extremely hot. And I have not checked the fan clutch. Would that make it overheat that bad?


Tiny
89jeepxj
May 23, 2011.
That would maybe let the fan, "FREEWHEEL" more than it should (this is sorta a fuel saving feature, less HP, to move the fan) If it sorta barely moves, then air is not pulled over the radiator fins, to cool it.

Is the A/C condenser, full of crap preventing air flow?

A reputable parts store, will be able to tell you if there is a problem with it. You can compare a new one with your old one (if yours is cold) Notice any difference in the way it turns, compared to yours?

How quick does your overheat? 5 minutes, 15 miles, etc.?

Does it drop in temp, if you are at speed. Heat up at idle mostly?

For sure, is it too HOT. Or does maybe a faulty sender or temp gauge just telling you it is?

The Medic


Tiny
CJ MEDEVAC
May 24, 2011.
Ok. Ill be sure to check that tomorrow. It does overheat in about 10 minutes at idle sitting still. And about the same while driving. And it is running extremely hot, smoking out of the top of the engine where the ccv air hose is.(Which is pretty oily inside) do you know of anything that will just give the engine a good interior cleaning.


Tiny
89jeepxj
May 24, 2011.
Wait for results, before you do this, you might even ask the "Been there awhile, Mature, auto parts store feller", his opinion too, about the overheat issue. I always gather all the info I can, before I go wild with new parts.

I'm more in tune with older Jeep CJs and Ford vehicles, I answer in those forums the most, however most overheating issues are common factors found in old or new rigs.

Search for vacuum leaks also, this will make you run lean.

As far as an engine cleaning, I use Marvel Mystery Oil, substitute a quart of oil for a quart of MMO, at your next oil change, Run it until the next oil change! It will also free up tappets (hydraulic lifters) that make the annoying tapping/ rattle sound in an older engine. Like I said WAIT, till you get the overheat issue straightened out.

Is your rig still in good shape, or has it been modified and stuff disconnected over the years?

The Medic


Tiny
CJ MEDEVAC
May 24, 2011.
The guy who had it before me apparantly did a engine swap from a 94 cherokee. He also lifted it and who knows what else. It was a cheap buy, just trying to work out all the kinks for a daily driver. I will say it worked fine when I got it, ran a little hot but not much until it busted the radiator hose, and after that, it was all downhill.


Tiny
89jeepxj
May 24, 2011.
Does the radiator still have a "fan shroud" on the engine side?

The Medic


Tiny
CJ MEDEVAC
May 24, 2011.