Guage temp VS engine temp.

I posted about running temps on my newly aquired 87 4.0, the stock guage as my other early XJ seemed to run to cool to be right. Anyhow this is after a 40 mile drive, the stock guage,new 195 thermo and clean system with 50/50 mix of coolant,it runs just above the middle mark between the 100 (170?) start and 210 center. The head where the thermo housing bolts on was 197, face of housing was 185 (fan cooling it probably) rear of head where the sender screws in was surprisingly 198 and the center of the head casting was 215 between cyls 3 and 4. Just thought ya might find this useful. Id say if the guage on mine at least was actually at 210 Id be in trouble or knocking on its door with engine meltdown.

Keep in mind that probably 90% of the people's jeeps here run at or around 210 on the temp gauge mark with no problems. Understandably the renix years seem to run at lower operating temps than the later years, but there are obviously going to be hotter spots and colder spots throughout the system, and you can be sure the engineers knew that when they placed the coolant sensor at its present position.

I just recently replaced my motor in my 90 with a motor out of a 89 with 68k on it. While doing this, I decided to run 2 temp gauges, 1 in the front by the T-stat and the stock one. The aftermarket one comes off the front of the engine and will read out at 197ish all day long and the stocker usually sits around 1/4 hot. The gauge in the front of the motor is the MOST accurate due to the simple fact that it is gauging the temp of the coolant as it comes out of the engine and back into the radiator. There are hot and cool spots on every motor and that is nothing to worry about. But I would say to monitor the gauge at the front is you want the most accurate readings.

Just my .02

LATA

pauldo39 said:

Keep in mind that probably 90% of the people's jeeps here run at or around 210 on the temp gauge mark with no problems. Understandably the renix years seem to run at lower operating temps than the later years, but there are obviously going to be hotter spots and colder spots throughout the system, and you can be sure the engineers knew that when they placed the coolant sensor at its present position.

Click to expand...

Agreed, but my 95 ran right at 205 with a 195 thermo and produced the same numbers on the head with the infared sensor, the 87 is basically the same numbers except the guage shows about 180 for some reason.

Hmm, I see what you're saying. Maybe that explains why a lot of people who have Renix jeeps say their normal operating temperature (when the cooling system is working correctly) is around 180 or so.

That what I was getting at, like me I thought the thermo was bad and it wasent running up to temp.

My 01 lives at 210 on the gauge, no matter if I'm on the highway or crawlin' with the A/C on. It dips a little on the highway, but not much. Course, the Hellas will do that to your airflow

TellicoReadyXJ said:

My 01 lives at 210 on the gauge, no matter if I'm on the highway or crawlin' with the A/C on. It dips a little on the highway, but not much. Course, the Hellas will do that to your airflow

Click to expand...

Same here on my '93 . ALWAYS a tick above the 210 mark . I thought it was high , but after reading about it and watching the gauge , it doesn't go any higher ...

Guess it's OK .

Yep, my '98 hangs out at 210 all day too, same as most other people. I would say it's nothing to worry about, unless your gauge is reading too cool and the temps are actually higher.