Hi everyone,
My 4.0 (new to me) had some ugly coolant, so I decided to change it. Never had overheating issues. Temperature needle would, at worst, touch the higher side of 210F (likely around 210, per my OBDII).
I drained the fluid and filled with distilled water several times before finally replacing the old thermostat (195F Motorad) with a Mopar 195F, filling with Zerex G-05, and installing a new radiator cap (18 psi).
In the process of burping the system, I left the radiator cap off until operating temp, and noticed my heater wouldn't work unless my radiator cap was on. The water pump heater hose was bone cold unless I had it on.
So, that was sorted to my knowledge.
Driving on the freeway was perfect. Once in high speed stop and go (drive half a mile at 45 mph, then hit a stoplight for 2 or 3 minutes), I noticed my temperature creeping up. I oberseved this several times. It would get to 220-230. This is after a while of stop and go with AC on. For the first 30 minutes, I'd see 205F pretty consistently.
One day, when completely cold, I opened the radiator cap and some pressure released and spilled fluid. I put the cap back on, and drove some short drives with no issues.
Another day, during extended stop and go, I got up to 220F again.
When I would hit these temperatures, I'd turn the AC off and it would be totally fine, dropping back to 205F in about 2 to 3 minutes.
Got my mechanic to look at it, he suggested I replace my radiator, so I did; it had some noticeable rust on the tubes and outside of the core. He suggested a 180F thermostat which I have in now. Has fresh coolant as well.
Now I understand using a low temperature thermostat has its problems, and I'm not a fan of this.
My question is, do you think my water pump could be causing these issues?
Fan clutch operates properly per some quick tests I did.
Mechanic doesnt susppect combustion leaks, and I have no symptoms. I also ran a successful compression test before buying the Jeep about 2 months ago.
Of course the Jeep runs colder on shorter drives, and colder than before, but it still seems to have an uncontrolled creep up in stop and go traffic.
2000 TJ, 4.0, 136k miles, 0331 cyl head
My 4.0 (new to me) had some ugly coolant, so I decided to change it. Never had overheating issues. Temperature needle would, at worst, touch the higher side of 210F (likely around 210, per my OBDII).
I drained the fluid and filled with distilled water several times before finally replacing the old thermostat (195F Motorad) with a Mopar 195F, filling with Zerex G-05, and installing a new radiator cap (18 psi).
In the process of burping the system, I left the radiator cap off until operating temp, and noticed my heater wouldn't work unless my radiator cap was on. The water pump heater hose was bone cold unless I had it on.
So, that was sorted to my knowledge.
Driving on the freeway was perfect. Once in high speed stop and go (drive half a mile at 45 mph, then hit a stoplight for 2 or 3 minutes), I noticed my temperature creeping up. I oberseved this several times. It would get to 220-230. This is after a while of stop and go with AC on. For the first 30 minutes, I'd see 205F pretty consistently.
One day, when completely cold, I opened the radiator cap and some pressure released and spilled fluid. I put the cap back on, and drove some short drives with no issues.
Another day, during extended stop and go, I got up to 220F again.
When I would hit these temperatures, I'd turn the AC off and it would be totally fine, dropping back to 205F in about 2 to 3 minutes.
Got my mechanic to look at it, he suggested I replace my radiator, so I did; it had some noticeable rust on the tubes and outside of the core. He suggested a 180F thermostat which I have in now. Has fresh coolant as well.
Now I understand using a low temperature thermostat has its problems, and I'm not a fan of this.
My question is, do you think my water pump could be causing these issues?
Fan clutch operates properly per some quick tests I did.
Mechanic doesnt susppect combustion leaks, and I have no symptoms. I also ran a successful compression test before buying the Jeep about 2 months ago.
Of course the Jeep runs colder on shorter drives, and colder than before, but it still seems to have an uncontrolled creep up in stop and go traffic.
2000 TJ, 4.0, 136k miles, 0331 cyl head