It's been a while since I've made any updates to this thread, but unfortunately that hasn't meant I've been just driving the Jeep.
Since the last post I've:
- rebuilt the CV joint at the transfer case end of the front driveshaft.
- replaced the TIPM.
- replaced front diff bushings.
- flushed the heater core twice.
- replaced the thermostat.
- rerouted the PCM wiring.
The driveshaft work and bushing took out some slop in the driveline, but also made it apparent that at 160k miles there is internal slop on the differentials and transfer case that shows up under very light loads.
The TIPM was to address the engine cut-out that I thought had been solved by the PCM replacement, but had returned during hockey season when driving further to get my son to practice. The TIPM didn't solve the cutting out, but did fix some other issues like the power windows. The power windows used to stop working randomly and the way to get it to work again was to open the window on the opposite side.
Googling revealed that Chrysler products still display codes if you cycle the key on/off the right number of times. This revealed a previously unseen code for the TCM losing power when vehicle was moving faster than 20 mph. More googling found that the "solution" was rerouting the PCM portion of the harness higher along the firewall. I figured it was worth a try, so I did that as well as raising the harness where is was resting on the ignition coils.
So far no stumble or shutdown since rerouting the harness.
Heat has been lacking this winter but coolant levels and engine temp were good. I flushed the heater core with garden hose, got all the air out of the system and heat seems to improve, but faded away with time. Running at higher rpm's would bring it back, but not to the levels of the previous winter.
I did notice the coolant level was dropping gradually, but it was hard to tell how quickly with the variable use the jeep currently sees. I had a theory that maybe there was air getting trapped in the heater core from a seeping head gasket, hence the coolant level dropping and poor heat. I also noticed the cooling system built pressure quickly.
My attempts to use a combustion gas tester showed no combustion gasses in the coolant, but there were some weird bubbling and boiling over captured in this thread (Blue).
Since the coolant level was already low from the boiling over yesterday, I went to the dealer this morning and bought a new thermostat ($126 😡). I replace the Gates thermostat I had installed when changing the water pump and bled the system, again. Heat was still poor so I popped the lines off the heater core and flushed it another time with the garden hose and bled the system.
Now I have heat and it's gone from needing to put the temp all the way to hot to try to warm the jeep, to air that gets uncomfortably warm if you hold hand in front of the vent for too long at that setting.
If heat fades again I'm going to add a filter on the inlet side of the heater core. I'd really like to avoid replacing the heater core, just because I don't want to pull the whole dash apart to fix it.
Now some pictures:
OEM on the right: