View Full Version : Operating temp?

August 29th, 2010, 19:49
Lately my jeep has been running hot, most times its right at 210 but every now and then it goes just over 210, not alot and never into the red. I talked to a few guys around town with the jeeps (4.0, auto, 1989) and they all say that this is the normal temp. I'm just kind of curious because if its not then I'm goin to upgrade the cooling system when I put a bigger tranny cooler on in a few weeks.

August 29th, 2010, 19:55
I just got done with a temp problem. Thermostat changed out, problem gone.
Seems like I have to put this into the yearly maintenance schedule.

edit: temp is now below 210.
Mines a 99 (open cooling system)

August 29th, 2010, 20:14
When does the temp go up--idle/stop and go, or on the highway?

If at idle/stop and go, what happens if you kick up the rpms?

There is a normal cycling of the thermostat. The Stant SuperStat Premium is built special and reduces the impact on the engine.

Last time the radiator was cleaned--not the 15 minute flush, the cleaner you put in and drive for 3-6 hours kind?

Coolant mix?

OEM system with a pressure bottle?

August 30th, 2010, 18:25
I don't know when the last time it was cleaned out but it has 250,000 miles and i've only put about 150 miles on it since i've had it. Temp goes up at idle and then goes back to 210 but its just over 210, still on the line but i can see a bit of the line on the left side. Whats this cleaner you're talking about?

August 30th, 2010, 20:01
Prestone or Zerex. Says "radiator cleaner" on it, check the directions on the container. Says drive for 3-6 hours, but it can be over several days.

Check the pressure bottle on the firewall. Any dampness on top of the bottle? The caps like to leak. Recommend replacing it with a Stant 10244 cap. Pros--lower profile so it isn't pounded by the hood when the bottle expands, reducing stress cracks in the bottle and damage to the cap; I screws down tighter and maintains pressure better; rated at 22 psi so it raises the boiling point of your coolant. Cons--NONE.

It is now September, so check your coolant to ensure a 50/50 mix ethylene glycol/distilled water. You should run that late September through early Spring, then when you are out of the freeze time switch over to a 30/70 mix, 30 ethylene glycol/70 distilled water. Ethylene glycol is good for two things--anti-freeze and corrosion inhibitors. It makes a lousy coolant.

When the temp goes up at idle try raising the rpm of the engine. If the temp goes back down it is a sign that the fan clutch is getting weak.