OK guys - I got a weird one for you!
’03 TJ 4.0l. 122k miles. Some PO along the way installed aftermarket radiator.
When I bought it, CEL bulb was not there. Deal I made with Seller is that it would pass emissions - and he said it would once the readiness codes set - just drive it around and come back. So I brought it home, scanned it - it’s got codes. Took it back to dealer, to,d him “ either the CEL bulb is burned out or not there”. Code is the engine isn’t getting hot enough. I tell him “it either doesn’t have the right stat, or likely no stat in it. Put a stat in it”. He gets his mechanic, no CEL bulb. They replace. Mechanic replaces temp sender, not stat. Taking Sellers word, I drive for 2-3 more days. cEL lights up, same code. At this point, easier for me to replace stat, I do - old stat was 165 degrees. I pet a 185 degree in.
All is well for the next 2 years - and then in a discussion of gauge and OBD scanner confirmation of temperatures - find that not all stats are made equal - get a specific because I’m still running too cool at around 180-190 degrees.
So, i order the specific Stant stat that everyone says to use on TJ’s. Did a full coolant flush and change at the same time. Life is good. Idiot gauge and OBD scanner say temps are up in the area of 208-215.
2 - 3 weeks later, wife and I are stuck on eastbound I30 traffic - and my dashboard lights up and buzzes like the circus is in town! Idiot gauge is in the red! Rut-roh! This could be bad as we were on a bridge going over a lake. But the engine never stuttered. We worked our way over to where we could hopefully pull off the road, but the engine never stuttered, never smelled, never sizzled.
Ive run engines got before - they don’t run smoothly for very long before it starts missing and you crack a head/blow a head gasket. Never happened.
Then as suddenly as it happened, everything was back to normal. 10 minutes later, still on the highway, it happens again. By the time we drove another 10 miles, it “cooled” off and went bonkers a couple of more times. We pull into a Buckie’s gas stop - I get out, lift the hood - no smell, no radiated heat from engine, radiator is full, overflow bottle is where it should be, etc., etc., etc..
I squeezed the upper hose a few times with the engine running and the radiator cap off. No bubbles. Or anything out of the rad cap hole. Fluid is mildly warm - temperature was probably in the upper 40’s, lower 50’s.
we were motorhome shopping that day - when we got through at Buckie’s we headed west on I30 stopping off at the various RV places looking to see what we could find. Around 1:00, some people I had contacted previously about a motorhome called and said was still available - in southeast Ft. Worth, 40 miles away. So we head that way.
The dashboard circus of lights and buzzers repeated itself, but didn’t happen as frequently as before.
We’ve only put about 200 miles on it since all that happened with only 1 or 2 more instances since.
And then Saturday morning, it doesn’t want to start, like it’s out of gas (new OEM Bosch fuel pump last June).
I forget to look, but it seems that the temp climbs very quickly at times after the Jeep has sat over night or for a few hours. Temps around here have not gotten into the 70’s since this started happening.
nomidea what temp sender the mechanic installed, but betting the O’Reilly’s special “Standard Parts”. Not to demean “ Standard Parts”, but I’ve read on here, and have followed as closely as possible, that our Jeep’s are picky about their sensors.
Am thinking to replace the temp sensor with OEM or recommended (I assume Bosch).
Not sure I trust the fan clutch either. But then engine never ran hot. Was thinking maybe the water pump impeller was loose on the shaft, but again, engine never seemed to run hot.
So, after you’ve wasted this much time reading of my plight - a few words of any ideas you may have to help narrow down what might be causing this weirdness?
Thanks for reading!
’03 TJ 4.0l. 122k miles. Some PO along the way installed aftermarket radiator.
When I bought it, CEL bulb was not there. Deal I made with Seller is that it would pass emissions - and he said it would once the readiness codes set - just drive it around and come back. So I brought it home, scanned it - it’s got codes. Took it back to dealer, to,d him “ either the CEL bulb is burned out or not there”. Code is the engine isn’t getting hot enough. I tell him “it either doesn’t have the right stat, or likely no stat in it. Put a stat in it”. He gets his mechanic, no CEL bulb. They replace. Mechanic replaces temp sender, not stat. Taking Sellers word, I drive for 2-3 more days. cEL lights up, same code. At this point, easier for me to replace stat, I do - old stat was 165 degrees. I pet a 185 degree in.
All is well for the next 2 years - and then in a discussion of gauge and OBD scanner confirmation of temperatures - find that not all stats are made equal - get a specific because I’m still running too cool at around 180-190 degrees.
So, i order the specific Stant stat that everyone says to use on TJ’s. Did a full coolant flush and change at the same time. Life is good. Idiot gauge and OBD scanner say temps are up in the area of 208-215.
2 - 3 weeks later, wife and I are stuck on eastbound I30 traffic - and my dashboard lights up and buzzes like the circus is in town! Idiot gauge is in the red! Rut-roh! This could be bad as we were on a bridge going over a lake. But the engine never stuttered. We worked our way over to where we could hopefully pull off the road, but the engine never stuttered, never smelled, never sizzled.
Ive run engines got before - they don’t run smoothly for very long before it starts missing and you crack a head/blow a head gasket. Never happened.
Then as suddenly as it happened, everything was back to normal. 10 minutes later, still on the highway, it happens again. By the time we drove another 10 miles, it “cooled” off and went bonkers a couple of more times. We pull into a Buckie’s gas stop - I get out, lift the hood - no smell, no radiated heat from engine, radiator is full, overflow bottle is where it should be, etc., etc., etc..
I squeezed the upper hose a few times with the engine running and the radiator cap off. No bubbles. Or anything out of the rad cap hole. Fluid is mildly warm - temperature was probably in the upper 40’s, lower 50’s.
we were motorhome shopping that day - when we got through at Buckie’s we headed west on I30 stopping off at the various RV places looking to see what we could find. Around 1:00, some people I had contacted previously about a motorhome called and said was still available - in southeast Ft. Worth, 40 miles away. So we head that way.
The dashboard circus of lights and buzzers repeated itself, but didn’t happen as frequently as before.
We’ve only put about 200 miles on it since all that happened with only 1 or 2 more instances since.
And then Saturday morning, it doesn’t want to start, like it’s out of gas (new OEM Bosch fuel pump last June).
I forget to look, but it seems that the temp climbs very quickly at times after the Jeep has sat over night or for a few hours. Temps around here have not gotten into the 70’s since this started happening.
nomidea what temp sender the mechanic installed, but betting the O’Reilly’s special “Standard Parts”. Not to demean “ Standard Parts”, but I’ve read on here, and have followed as closely as possible, that our Jeep’s are picky about their sensors.
Am thinking to replace the temp sensor with OEM or recommended (I assume Bosch).
Not sure I trust the fan clutch either. But then engine never ran hot. Was thinking maybe the water pump impeller was loose on the shaft, but again, engine never seemed to run hot.
So, after you’ve wasted this much time reading of my plight - a few words of any ideas you may have to help narrow down what might be causing this weirdness?
Thanks for reading!
