Ok, bought a 1998 ZJ 5.2L Quadratrac. First time in a Jeep and I had no idea these ran so hot. Short of putting in an alum two core rad and elec. fan what can I do to make it run 180 deg. Chevy guy my whole life and 210 to 215 deg. scares the crap out of me. I've heard that you have to reprogram the ECU if you put in a 180 Deg. thermostat and you have to run a monster elec fan to replace the mechanical fan. Just want to be cool, thx.

 

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210 is normal. It has a195 degree thermostat from the factory, so 180 is not going to happen.

 

If you're a Chevy guy, you should know they ALSO have a 195* thermo. I wouldn't be concerned until about 240*, THEN I'd shut it off. 180* is the limit for nonpressurized systems, as in 50's cars. Some cars today have a 210* thermostat.

If I remember correctly, some Chevies don't even have numbers on the guage, IF they have a guage at all! Some of the mid 60's GM cars only had a HOT light!

 

Thanks for the feedback, it's a big help.

 

Is 210-220+ OK for a 2000 Grand Cherokee Laredo 4.0?

 

Yes.

 

Q? So my other jeep 4.0 95 lerado runs at 180 all the time why would 2000 run at 210-220+?

 

Emissions reasons.

Same reason, if you might be referring to a carb'd Chevy, anyway. The reason for the 195 degree t-stat, and 210-220 degree e-fan operation(in most late 90s, thru 2000s OBD2 cars) is for emissions and correct cat operation.

 

Today's cars run a much leaner mixture for a clean burn and more power per cubic inch. They also produce a lot more heat that has to be taken care of by the cooling system. The whole thing has it be held to a fine edge to prevent distruction of internal parts. The exhaust valves are high temperature Stellite or they would melt. What a lot of people don't realize is the lower the octane rating of the fuel, the hotter it burns. In high compression engines, 80 octane fuel explodes, doesn't burn smoothly. That's called "Detonation" or "ping". Most engines are set up for 8 to 1 compression and 87 octane fuel. This provide maximum power and a complete burn. The PCM is designed to keep this fine edge sharp.

School's out.