Low Operating Temperature

Last week I had a shop replace the radiator and tstat. . Prior to this my jeep would run around 210-220 and once or twice under heavy driving it would overheat.

But now it reads 140 when i am driving down the freeway and 150 when i am at a stop or in traffic. I had it get up to 190 the other day while parked and idling, but i have only seen it get that high the one time.

So did they put in a bad tstat? or did they mess up the temp sender when they redid the radiator?

- Is it possible i am actually running at 140?
Or is it more likely
- Am i running at 210 and the gauge only says 140? (causing the aux fan to never kick in at the right time)


Last... if i leave it the way it is what would be the repercussions.

My vote is bad sender. Can it really run at 140? I really don't think so. People that run cooler thermostats and high flow housings on their XJ's (160-165) still get up to operating temp, it just takes longer since the stat opens up at 160ish. I would have it checked out because it could cause some engine damage if that aux fan doesn't kick in when needed.

Has the CEL light come on? It will throw a code if the motor does not come to operating temp in a certain amount of time.

It is possible that the stat is not in the housing correctly.It could have slipped down,and still the housing could be tightened enough to not leak.Ask me how I know:doh: Code will be 17

Wayne

yeah... no codes have been thrown yet and i have put about 100 miles on it.

i called the garage and they said they i shouldnt be concerned if its that low because the radiator must just be working really well.. lol..

your rig is meant to run at a certain temp. too low is NOT good and for a garage to say "oh well" is b.s. you're xj is going to run rich if it thinks you're not up to temp. i'd track down the problem if i were you.

XJ96Classic said:

yeah... no codes have been thrown yet and i have put about 100 miles on it.

i called the garage and they said they i shouldnt be concerned if its that low because the radiator must just be working really well.. lol..

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What a pile of crap that is. Unscrew the coolant sender and see if they used teflon-peel it off if they did. It could result in a poor ground. Make sure the cooling system is burped too.

i would say its a bad thermostat or bad sending unit.

as said, its very bad not to have a computer controlled fuel injected engine to run lower than the operating temp(190-210). it will produce high emmissions because the combustion chamber is not getting hot enough. it also increases wear on any moving part of the engine. cooler doesnt always mean better. the engine will also run too rich and it will get poor mileage.

I recently installed a high flow 180 degree thermostat, high flow thermostat housing, a 3 core radiator, water pump, upper and lower hoses, and heater hoses.

Mine runs between 200 and 210, very close to 210 cruising around off the highway. If I run 65 to 80 mph it will run 210, or a little over for about 3 miles and then it drops to 210 steady.

I don't think it is possible for it to run 140. Get you a mechanical temp gauge and check it, or if you have, or have access to an IR scanning thermometer, point it at the thermostat housing. It will be a little cooler, but maybe by only a couple of degrees of the coolant.

If they did all this work and now is running lower than usual I would take it back to them and complain(since the job wasnt done correctly). If they keep fighting you about the radiator is working REALLY WELL I'd tell them straight up its B/S you need to be at 210.