lower temp thermostat needed

M

Mike1

New member
Hi

I have a 98 Cherokee XJ 4.0L Auto. The normal factory thermostat is fitted kicking in at 195. Are there alternatives lowering the standard thermostat temperature, thus in theory allowing the vehicle to run cooler. Where would one purchase these thermostats and how cool can you go? Would it damage anything running cooler?

Is there a reason why these vehicles run hot so quickly, it seems to be abnormal?

Thanks Mike
 

My 83 CJ7's standard thermostat was a 195. Someone had put a 165 in it before I had it. I put a 195 back in and noticed an improvement in gas mileage. In my opinion it is a bad idea to change to a different temp range thermostat for a fuel injected vehicle. The computer is set up for one range and when you change to another range it usually confuses the computer causing it to even set codes sometimes.
 
If you lower that 98 you may have a "Check Eng" Light come on. If it works anything like a TJ. The Temp goes down and it starts adding more fuel to bring the Temp up to normal. then the Computer will fault and let you know it.
 
any auto parts place should have different temp thermostats. Though, most newer vehicles run better hot than cold. Ths computer adjusts settings for the temp and you can run alot hotter than older cars.
 
Hi

Not overheating, the mechanical and electric fans kick in as required. When offroading especially after long trips at high speed on the freeways, the JEEP seems very hot, and takes a long time to cool down. Friends have also commented that it seems to run a lot hotter than their vehicles, which I think is true.

Also remember that we are in South Africa and temps regularly get up to 36 degrees centigrade in the shade!

I have also fitted a gearbox cooler to bring temps down for the autobox. It is infront of the radiator.

Any suggestions?

Mike
 
Have you gotten a bigger radiator at all? A lower temp t-stat won't do you any good if you can't get rid of the heat fast enough....
 

I don't think a lower temp thermostat will make you run any cooler, it just opens sooner. The jeep's only gonna run as cool as the engine and radiator allow.

XJ's normally run hot.
 
You can run a slightly colder thermostat with OK results, don´t think I´d run lower than 185 or you gas mileage is going down noticiably. I´ve run a 190-192 with acceptable results. Have failed an emissions test with a 185, passed with a 192, if you have emission testing, something to think about.
I have a sticky thermostat now (gonna change soon), have noticed the idle changes with the temp. when the temp. is a little low, it idles higher and when a little hot it idles lower. In other words, the fuel to air and idle IAC, are somewhat controlled by motor temp.
When does yours over heat? If it´s at idle, the first suspect is a fan cluitch, they don´t fail all at once, but in stages. May start failing anytime after about five years old.
Also if you have to add much water/or coolant the calcium/kalk, settles to the bottom of the radiator and builds up over the years. Cutting off some of the flow.
Most guys that run in the hot country, at low speeds, usually change to a three row radiator, at some point. Many add hood vents.
A motor that is running lean for whatever reason, will overheat. Sometimes overlooked, usually happens at higher (top) speeds though.

http://www.xj-armor.com/electronics.htm Lets you turn on the aux fan before the temp. gets too high.
Running the air-conditioner at low speeds for extended periods, is gonna overheat it most times, no matter what you do.
Many guys have said hood vents help, hot air backs up in the top of the motor, hood vents, help move the hot air out of the motor compartment.
Couple of possibles are, if the lower radiator hose has been replaced, the replacement is sometimes missing the spring (or it´s too short) to keep the bottom radiator hose from partially collapsing at higher RPM´s. Another is the A/C condensor or the radiator partially plugged with bugs, the fuzz off of cotton wood trees, mud or pollen. Sometimes the outside of the radiator looks fairly clean and the blockage is between the layers, where it´s hard to see.
Last note, the thermostat has changed some over the years, it´s some different from model run to model run. Be carefull what you put in there. On some model runs, the thermostat has a slightly lower profile than most standard thermostats.
Hope I´ve helped a bit.
 
88Wrangles said:
You took your thermostat out?? And you Jeep never overheats?
Click to expand...

Taking a thermostat out will open the path for coolant, so it would not be cause for overheating. A lack of heat in the winter, yes, but overheating, no.
 

TwistedCopper said:
88Wrangles said:
You took your thermostat out?? And you Jeep never overheats?
Click to expand...

Taking a thermostat out will open the path for coolant, so it would not be cause for overheating. A lack of heat in the winter, yes, but overheating, no.
Click to expand...

Never seen it on an XJ, but V-8 Chevs, would push the coolant through there so fast (without a thermostat), it didn´t have much chance to get rid of the heat. Under certain conditions (desert country) , you´d end up with a fairly homgenous temp. that was often a little/or a lot too high. Was a warning letter from Chev, about that way back when. Said the system needed the thermostat to work properly, removing the thermostat could cause overheating, didn´t seem logical, sparked a large and heated (pun)debate.
The real name for radiators is heat exchangers (from the coolant to the air), modulating the flow is part of the process. Physics, is sometimes an illogical exercise. What it does, is more important than what logic says it should do.
 
Never heard of that. Those things must have had really good water pumps. I had a 350 Cutlass ('77) that ran without one for a year. No heat that winter.
 
What vehicles have you had?

My themrostat hung open winter before last, sure enough messed up my heater, full blast it was barley warm. Took forever for the motor to warm up. Never did get much above about 160. Every time it would dip below about 140 my motor would idle pretty high. Exhaust always smelled like unburnt gas and roasted cat..
 

that's about how mine smells now that I took mine out

yup smells like pole cat stew
 
88Wrangles said:
You took your thermostat out?? And you Jeep never overheats?
Click to expand...

that's correct no thermostat and it never overheats
a thermo is really a regulator anyway, it opens only when the engine reaches a certain temp (warm up) and then allows the coolant to flow through the block to regulate the temp, I've got a totally rebuilt cooling sys, and good fluid (50/50 mix -34 on the test and it runs cool all the time
 
Like mudderChuck said, some vehicles actually will overheat without a thermostat, which is why I asked. No offence, but what makes you think it'll run better without a thermostat. Most engines have the most power/torque when they are warmer (not too warm of course). I've done a fair amount of research on this subject in the past, and could never think of any benifit of having nothing there (i.e. thermostat) to control the temp of your engine.
 

I have to agree with Mudder.
The coolant system is designed for a specified flow rate and taking the thermo out could make it run through too fast for good cooling. If you can get a temp reading with a good IR gun where the coolant goes into the top of the radiator and then at the bottom where it exits, you should be seeing about a 30 degree drop. Anything less and the radiator may be partially plugged.

My XJ runs at 195 to 200 just like most other 4.0s out there.
 
You must log in or register to reply here.
Back
Top