• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Operating temp

T

Tacowhip

NAXJA Forum User
Location
New Jersey
My 4.0 got up to 215ish riding around town. Thought that seemed a little high. What is the average operating/coolant temp once warmed up? Thx


Sent from my iPhone using Tapatalk
 
200 - 210 is pretty much the norm.
 
My 98 XJ manual says something like this about electric fan operation

Electric cooling fan 4.0L: With or without A/C request the electric fan will come on only when the coolant temperature is at least 106° C (223° F), and will remain on until the coolant temperature drops to 103° C (217° F) or below. Regardless of coolant tem- perature, When air conditioning system pressures reach 2068.5 138 kPa (300 20 psi) the electric fan will engage and continue to run until the A/C system pressure drops to 1620.3 kPa (235 psi) mini- mum, then the electric fan will shut off.
 
IIRC there was a service bulletin about flashing the computer on late models that has the efan kick on 10° sooner. Not sure how it affects the AC programming.
 
Bent said:
IIRC there was a service bulletin about flashing the computer on late models that has the efan kick on 10° sooner. Not sure how it affects the AC programming.
Click to expand...

I would like to see that service bulletin. My efan definitely kicks in at over 220F
 
superslow said:
I would like to see that service bulletin. My efan definitely kicks in at over 220F
Click to expand...

I want to look into it as well.
I'll see if I can find it. It's here in OEM tech, and within the last 6 months.
I should have subscribed to the thread. :doh:
 
If your electric fan is switching on and staying on, but engine temp is not dropping down to the middle of the temp scale, then you probably have a cooling problem (e.g., your water pump is going bad, bad thermostat)

If your electric fan is not switching on, then you probably either have a problem with the fan electronics (e.g., bad temp sensor, blown fuse, burned out fan motor)
 
There is a lot of ambiguous information in this thread. What model year? Are you going by the dash gauge or a scanner?

In the last years, 2000-2001, the gauge was "dumbed down" so it rarely moves the next tick mark past center unless there is something wrong, or extremely high load, like driving across the desert passes in the summer with the A/C on. I forget the specifics but it will hover closer to center until about 236F when the PCM puts it at the beginning of red and at 247F the PCM buries the gauge.

Earlier models the gauge is more or less what it is.

I always thought my Red 97 was running hotter than my Silver 01 based on the gauges. But I hooked up scan tools to both and if anything the 01 runs a bit warmer because of the pre-cats but you'd never know that from looking at the gauges.
 
Its always best to install a couple good quality gauges with finer measurements if you need to/like to keep track of things like the temperature, oil pressure, etc. Temp. and oil press. are the two main ones that I keep track of. And as stated earlier, the factory gauges are VERY general. They are adequate, but general.
 
OEM thermostat is 209 degree running temp. My xj does not stray over or below that under load or just cruising. You may want to get some of that stuff that additive that flushes the gunk out of your cooling system, new water pump if its not new, new radiator cap and fresh coolant
 
Many times an apparent high operating temperature issue is actually a mis-calibrated temperature sender.
Verify the actual coolant temp with a infrared thermometer, aimed at the temperature sensor. Find the hottest spot and consider it to be the actual temp.
My 2001's sensor was out of calibration and I tried several new sensors before finding one that showed the actual temperature, when read on a scanner.

A mis-calibrated sensor, besides not showing the actual operating temp, can cause the engine to run rich or lean, depending if the sensor reads high or low.
A sensor that reads low can keep the engine in open loop longer than necessary.
 
md21722 said:
There is a lot of ambiguous information in this thread. What model year? Are you going by the dash gauge or a scanner?

In the last years, 2000-2001, the gauge was "dumbed down" so it rarely moves the next tick mark past center unless there is something wrong, or extremely high load, like driving across the desert passes in the summer with the A/C on. I forget the specifics but it will hover closer to center until about 236F when the PCM puts it at the beginning of red and at 247F the PCM buries the gauge.

Earlier models the gauge is more or less what it is.

I always thought my Red 97 was running hotter than my Silver 01 based on the gauges. But I hooked up scan tools to both and if anything the 01 runs a bit warmer because of the pre-cats but you'd never know that from looking at the gauges.
Click to expand...

Thanks this helps explain the behavior of the gauge in my '01 when the water pump failed.
 
lazyxj said:
Many times an apparent high operating temperature issue is actually a mis-calibrated temperature sender.
Verify the actual coolant temp with a infrared thermometer, aimed at the temperature sensor. Find the hottest spot and consider it to be the actual temp.
My 2001's sensor was out of calibration and I tried several new sensors before finding one that showed the actual temperature, when read on a scanner.

A mis-calibrated sensor, besides not showing the actual operating temp, can cause the engine to run rich or lean, depending if the sensor reads high or low.
A sensor that reads low can keep the engine in open loop longer than necessary.
Click to expand...



What brand sensors were you using? My 98 takes a lot longer to warm up than my 01. I know the purpose of the redesigned head in 00 was to get it to warm up quicker but my 98 takes a very long time. I replaced the temp sender in the 98 with whatever they gave me at NAPA. Probably a standard or something. It also might be the Stant thermostat which I read about others using them and they flow too well and don't allow the engine to warm up completely or quickly
 
You must log in or register to reply here.

Similar threads

C
Transmission
Replies
3
Views
2K
Saudade
Saudade
V
High temp woes
2
Replies
21
Views
391
Vitzaa
V
T
Temp gauge stuck ?
Replies
6
Views
2K
Tonyt22
T
O
0331 Strikes Again...?
Replies
11
Views
296
Ol Blue
O
T
OBD2 coolant temp readings
Replies
2
Views
1K
maxbraketorque
M
Back
Top