mustafacomertt

Hello everyone. I know there are many similar topics... I've read them all, and I've been working on this issue for a year without finding a solution. By the way, I'm writing from Turkey, my English is weak, so I will proceed using translation. Thank you in advance for your understanding.

First, let me tell you about my vehicle;

1992 Jeep XJ Limited 4.0L High Output
6" Lift
32x11.5 R15 Tires
Standart 3.55 Axle Ratio(Rear 8.25, Front Dana 30)


During the summer months only, my vehicle runs at around 215F in city driving and between 230F on over 50mph highways and uphill drives. Below, I list all the procedures I have undertaken. It doesn't drop below 210F with the ac off.

1-New Waterpump (GSP WP900091)
2-New Thermostat (Motorad 160F-195F/I tried both of them. I drilled 1/8 holes towards 12 o'clock on both of them. Beforehand, I conducted a hot water test using a thermometer.)
3-New Electrical Fan(Crown 9 wings, 97-01) (I have checked my electric fan many times, it works on time. In addition, I made a switch inside.)
4-New ZJ HD Fan Clutch
5-New Serpentine Belt
6-New Radiator Cap 16ps (Motorad)
7-Despite my old radiator being perfectly clean, the new radiator (NRF50321)
8-I cleaned out the cooling channels in the engine, they are spotless. I also replaced the heater core and i applied a 50/50 mixture. I purged the air
9-New Radiator Hoses. (Lower hoses with spring)
10-I gave up on the transmission cooler on the radiator and bought a new, large transmission cooler.
11-Lastly, we decided to replace the cylinder head gasket. When we removed the cover, the gasket was intact. We conducted a crack test on the cover, and no cracks were found. While dismantling, we renewed and restored all components on the cylinder head.
12-I took off everything in front of my car that could block the wind. I washed the radiator and AC condensers fins, cleaned between them, air flow is very good.

By the way, I measured all cooling components of my vehicle with an IR thermometer. Thinking the gauge might be inaccurate, I also used a different temperature sensor and gauge.

I'm listing the readings I took during the measurement;

Dash gauge: 212-215F

Thermostat house: 210F
Upper Hose: 203F
Lower Hose: 182F
When I tried measuring around the sensor located behind the cylinder head, it was around 170-195F degrees.

The numbers averaged out like this.

By the way does not leak water, I have checked it many times.Despite these efforts, we haven't made any progress. This situation has really worn me down in every way... Please, someone help because I feel like I'm going crazy.



This is my car...

Ermond

I too

have a “93”,and the temperature reading you have are similar to mine. I’d say quit worrying about it and just enjoy your XJ. Nice ride, by the way here is my Jeep

mustafacomertt

i guess, i have no choice...

Jim Malcolm

How old is the catalytic converter? One that's getting clogged can cause the engine to run hot...

mustafacomertt

First of all, thank you for your interest. My car is a 1992 model with an OBD I engine and because it has only one o2 sensor, i had removed the catalytic converter. I forgot to include this in the list of items i mentioned earlier.

Jim Malcolm

It appears that your gauge may be as much as 20F higher than reality. Upon starting up from cold, it should sit at the thermostat temperature, 195F, for a bit until the radiator and the rest of the coolant get up to temp. Have you looked for that "pause" and compared it to the thermostat? Does the gauge read 220F when the fan kicks on? What's the air temperature?

Have you added a short piece of wire from the metal structure of the dash over to the kick panel? The dash in these XJs is only grounded through the mounting bolts.

50/50 mix is good for down to -32C. You can run as low as 30% coolant, which will protect down to -12C, while transferring heat better. There's also products like Water Wetter. Always use distilled water.

3.55s and 32s doesn't help any...

mustafacomertt

I didn't directly perform the comparison you mentioned, but when i compared the thermostat housing with the gauge while the engine was hot, i observed that there was only a few degrees difference between them.

Let's come to what you mentioned about the wire process... I haven't heard of such a thing before. yes, the sensor behind the cylinder head is a single-plug sensor and it grounds directly from the mounting bolt. Should i try this? Why not? I'll try it at the first opportunity

By the way, right after solving the overheating issue, I'm thinking of switching to the 33-4.56 combination. I've got the parts, but haven't had the chance to install them yet.