4.0 running too hot?

OK - here's the scoop

2000 Cherokee, 63k miles - upgraded to the 3-row brass/copper radiator from radiators.com (CSF brand) - flushed the cooling system, new robertshaw hi-flow thermostat (195), new hoses, new fan clutch, added a seperate tranny cooler. The new fan clutch is fine, and the aux fan works fine - the system has been sufficiently burped, and has a mix of 50/50 distilled water & antifreeze, plus a bottle of Redline's Water Wetter. (Yes, I'm anal! )

Well, running down the highway, it's running just under 210 (about the width of the gauge needle) - in town, particularly sitting, but if running at 30mph or lower, it runs over 210 (again, about the width of the gauge needle) - once it gets there, it takes a quite a bit to come back down under 210. The aux fan will come on (even with the A/C off) when idling, so it's doing it's job ...

I've went back with an infrared heat gun and checked a few areas. The thermostat outlet is about 225, as is the inlet side of the radiator - (when the needle is reading just over 210) - isn't that a bit on the hot side? I've seen it get upwards of 230 ...

Any advice, or is this normal? (BTW - I have searched - haven't found anyone who has checked with the infrared gun, which is what I'm hoping to have answered here ... )

MightyXJ said:

Well, running down the highway, it's running just under 210 (about the width of the gauge needle) - in town, particularly sitting, but if running at 30mph or lower, it runs over 210 (again, about the width of the gauge needle) - once it gets there, it takes a quite a bit to come back down under 210.

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That's exactly how my '01 runs in the summertime. After reading some past threads, I concluded that around 210 was fine for the 4.0.

thats actually good .....when i sit idle mine goes past the 210 needle a little bit more than yours.

Pete

Sounds OK to me. The 4.0 is designed to run in the 195-220*F range.

thats normal

Well, guess I AM a little old-school - I come from the "hot oil - cool water" folks.

Thanks all!

With the exception of the heater core, my entire cooling system is new. Pump, hoses, t-stat, fan clutch, hoses, all new.

Mine runs EXACTLY like you describe. A teeny bit below or at 210 when moving, a teeny but above if now.

97, just under 90k.

Mine runs that hot too. A little under 210 driving down the highway, a little above 210 sitting still. 2000 Sport 76000 miles.

Alright, let me tell you about mine. I just swapped in a 3 core radiator, seperate tranny cooler, 180 degree failsafe thermostat, upper and lower radiator hose. One heater hose. Radiator cap, 50/50 glycol mix, and one bottle of water wetter. Clutch fan is tight, only turns about half a turn when spun by hand, and you can hear it engage, disengage when you spin the crap out of the engine. Electric fan comes on and stays on at anything above 200. New water pump and new head gasket. A bottle of preston radiator flush, and then backflushed it. Hooked garden hose up to heater hose out put on thermostat housing, removed radiator cap and flushed water. then reversed, then unhooked upper hose, reconnected heater hose and flushed through radiator. Today mine hit oh about 260, and even when it dropped back down the engine detonated all the way home even though the gauge showed it was not overheating.

i'm in south texas where it gets fairly hot. my 87 xj in the summer normally runs one mark under the 210. i don't remember exactly but i think it's 205. my aux. fan comes on at 210. everytime i wheel it my jeep gets up to 210. if 210 is a normal temp for the xj, is there a way to adjust the aux fan?

cruzmyxj said:

Alright, let me tell you about mine. I just swapped in a 3 core radiator, seperate tranny cooler, 180 degree failsafe thermostat, upper and lower radiator hose. One heater hose. Radiator cap, 50/50 glycol mix, and one bottle of water wetter. Clutch fan is tight, only turns about half a turn when spun by hand, and you can hear it engage, disengage when you spin the crap out of the engine. Electric fan comes on and stays on at anything above 200. New water pump and new head gasket. A bottle of preston radiator flush, and then backflushed it. Hooked garden hose up to heater hose out put on thermostat housing, removed radiator cap and flushed water. then reversed, then unhooked upper hose, reconnected heater hose and flushed through radiator. Today mine hit oh about 260, and even when it dropped back down the engine detonated all the way home even though the gauge showed it was not overheating.

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OUCH - I fell a helluva lot better about my just under/just over 210 .... good luck with yours .....

No luck with mine, the head is cracked.