Temperature Question

[oneirishpollack]

Hi all,

Can you help me sleep at night?

What is the a "normal" temperature range for a (93) XJ in the following scenarios...

1. Idle (no AC or heat on)
2. Driving in-town 45 MPH or less (no AC or heat on)
3. Driving on the highway 65 MPH+ (no AC or heat on)unning
4. Idle with AC running

 

[cruiser54]

210 degrees fahrenheit

 

[DanB98TJ]

My '96 runs at 210* (or a needle-width to either side) during freeway driving, AC on. In town it will creep up to 220 or so, a touch higher at traffic lights. All with the AC on...been 108* for the past few days so it has been on all the time.

I just installed a ZJ fan clutch, new 195* thermostat, new hoses, and a new 2-core all metal radiator. Had some issues wheeling a few weeks ago that are *hopefully* fixed by all the above....

 

[ehall]

1. Idle (no AC or heat on) 210
2. Driving in-town 45 MPH or less (no AC or heat on) 200
3. Driving on the highway 65 MPH+ (no AC or heat on)unning 195
4. Idle with AC running 210-220

Heat transfer is mostly from engine to coolant to air (some heat transfer directly from engine to air too). The faster you go, then the faster the heat is transferred--the water pump pushes coolant through the system faster (~2000 RPM on highway vs ~500 RPM at red light), and air flows through the radiator faster (full frontal exposure at ~60 MPH vs small openings at ~500 RPMs when idling). A/C should not make much of a difference when everything is moving, but it can accelerate heat buildup at idle.

 

[carves]

Hi all,

Can you help me sleep at night?

What is the a "normal" temperature range for a (93) XJ in the following scenarios...

1. Idle (no AC or heat on)
2. Driving in-town 45 MPH or less (no AC or heat on)
3. Driving on the highway 65 MPH+ (no AC or heat on)unning
4. Idle with AC running

According to the FSM ...

1/. Prolonged idling is an "abnormal" condition that may cause overheating,
2/. Driving in town should be fine unless an "abnormal" condition such as slow traffic or traffic jams, causes overheating,
3/. High speed driving / uphill grades is another "abnormal" condition that causes overheating,
4/. A/C operation normally means the additional aux fan is fitted to compensate.

There is no "normal" stated operating temperature for the 4.0l engine. Probably because running temperature varies, depending on location and use ...


It is typical for them to run at 210'f in most scenarios tho .... with a well maintained cooling system.