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Jeep Cherokee running hot

I've got a '96 Jeep Cherokee 4.0L with 100k miles. I live in Las Vegas and spend months driving in 90-100+ temps (I've seen 120+ a few times), often off-road on grades at relatively low speeds.

Over the past two years the jeep has begun to climb up to the 240 degree mark on the thermostat and not come back down unless I turn it off and wait a while. Knowing the neglect I've put on the vehicle, I just put in a new 3 core radiator, a high flow water pump, and a new 195 thermostat, along with flushing the whole system with some prestone product. I also put in an electric fan in replace of the mechanical fan (I'm still debating weather this was a dumb idea.)

Nonetheless the vehicle can now hold steady between 210-215 in 90+ temps with the AC on and the vehicle stopped. It still seems a bit high.

My question is, ignoring the actual cooling components what engine parts could cause my engine itself to generate more heat? I've never done much with my fuel/exhaust system. I've got all original sensors (o2 etc..) and never used fuel injector cleaner. I've begun noticing a loss in fuel economy along with the heat problem and it does seem to idle a little rougher then when she was younger.

Any thoughts would be appreciated.

Thanks,

Matt

Reply to
s
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Well... I would guess the clutch on your original mechanical fan wore out.

You are describing the symptoms perfectly....

It is a cheap easy repair....

You have a 195 t-stat, runn>

Reply to
Mike Romain

The old system was slowly plugging up and losing efficiency, but the electric fan doesn't have the power of the mechanical fan by a long shot. A better idea would have been an electric fan in addition to the mechanical fan. I suspect that just putting the mechanical fan back in (assuming the fan clutch is OK) will solve most of the problem.

Reply to
Will Honea

Mine's an 88 - anything plastic is getting brittle by now so I just expect to break things like that when I pull them. I keep a sheet of

16-18 guage galvanized steel in the garage so that if something cracks I just cut a patch of steel, gunk it up with Automotive GOOP and pop-rivet the thing back together. Adds character to the beast. Seriously, no piddly-assed little electric motor is going to pull the air that the mechanical one will. I figure that the aux fan on mine is just that, a little help whe needed. It can be unplugged and I never miss it. It's all about the volume of air you put thru the radiator.

See above - it's CFM that counts in the end.

Now there you have a point.

At my age, noise has ceased to be a major problem - after over 4000 hours flying jets I could frequently use an ear trumpet, anyway.

I ran mine all over West Texas, last summer especially, 25-30 kt headwinds and 100+ temps with the A/C going full bore and never saw the guage get above the center mark even when I forgot to plug the aux fan back in after I had it off to swap the serp belt. I was also hauling some heavy loads around the farm pulling 6-8 tons on a flatbed in 4LO. Best I recall, there was one day that we hauled over 100 tons total up the hill from the back field to the dock - about a mile each way - and it ran rock solid there as well. The only time I've ever seen mine above the center mark on the guage was last weekend pulling long grades at 10-12,000 feet in 3rd (damned 3.07 diffs!) and it was either on or just barely above the line. That's with the original (at least the original style) 2-core radiator in this miserable closed system they used back then. I wouldn't think twice about replacing the clutch versus an electric myself.

Reply to
Will Honea

Well I didn't even get to the second day of testing. Mid way through my offroad trip saturday I had to pull off the trail because the Jeep was getting up around 240. Turns out the electric fan blades had made contact with the radiator housing and bent over a few blades and was now stalled. In retrospect I think it probably happened fairly earlier in the drive. I think its a testament to the other components in the cooling system that I made it as far as I did. This was during a 9 mi 7%-9% grade with tons of big rocks and ruts to negotiate very slowly.

I ended up hooking up my aux. electric fan to come on at 195 (like the main fan would.) With just this fan I made it up the last .5 mile of the climb and the 100miles back to town without ever going over 215.

I guess its time to put the mechanical fan back on.

Matt

Reply to
mpower

I think I am driving in one of the most hostile deserts in the world. Driving grades in 125 temps in and out of Death Valley and elsewhere in the Mojave can be awfully hard on a car (and a driver.)

Matt

Reply to
mpower

Reply to
L.W.(ßill)

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