Normal engine temp?

[Jeff Allan]

I’ve had other TJs and they’d run right at 210. Wondering if this is within normal range.

I got this TJ earlier this year. Very low miles. Took into a shop had some electrical issues fixed. Also had the system flushed, t- stat changed, they said they used a Stant 195. My heater works pretty well, gets warm, but not as well as I remember my others did. They could get so hot, I couldn’t keep my fingers on the vent.

 

[Jerry Bransford]

Nope that's not normal. If that's with the engine fully warmed up I'd say they either installed the wrong temperature thermostat, it should be a 195 degree model, or they installed a defective thermostat.

 

[beaufrusetta]

Looks a little on the low side to me...mine is always riding left of 210 or on it in the summer. Maybe the heater core is plugged up a bit?

 

[Jeff Allan]

Heater core was flushed, also fill and bleed coolant. They said they tested heater and it’s showing 150 F at the vents. I’d think that’s hot enough but it doesn’t feel that hot. Not like the other three TJs I’ve owned.

It seems to run fine. The shop owner tells me it’s good for it to run on the cool side.

Should I just change the t-stat first? Or what else can I check?

 

[Jerry Bransford]

Heater core was flushed, also fill and bleed coolant. They said they tested heater and it’s showing 150 F at the vents. I’d think that’s hot enough but it doesn’t feel that hot. Not like the other three TJs I’ve owned.

It seems to run fine. The shop owner tells me it’s good for it to run on the cool side.

Should I just change the t-stat first? Or what else can I check?

If that engine was thoroughly warmed up and had been driven for a while at that temperature, again they either did not install a 195 degree thermostat as they claim or it is defective.He is wrong about it being good for it to run cooler than it was designed to run at and the PCM was programmed around, he is simply trying to avoid doing any additional work he won't be paid for.

 

[beaufrusetta]

Heater core was flushed, also fill and bleed coolant. They said they tested heater and it’s showing 150 F at the vents. I’d think that’s hot enough but it doesn’t feel that hot. Not like the other three TJs I’ve owned.

It seems to run fine. The shop owner tells me it’s good for it to run on the cool side.

Should I just change the t-stat first? Or what else can I check?

A new t-stat is like $7 on amazon. Can grab a new felpro gasket for less than $5 too! This is me assuming you're running the same setup I have (4.0 6cyl) - not sure if the 4cyl is different. It's an easy enough fix for cheap to see if that was maybe the case.

I had a t-stat fail open one time...and it ran oddly cool at night time...never got up to operating temp after driving around for a while.

 

[KingCarGuyZ]

https://wranglertjforum.com/threads/how-hot-is-too-hot.42028/
just to link even more info

 

[RMETeeJay]

Before you get into anything, I would grab an OBDII reader and see what temperature is getting reported to the PCM. It should be close to 210 once fully warmed up.

 

[Jeff Allan]

I’m going to check it with a scanner tonight and see where it’s at. Then probably try another T-stat if needed

It’s been in the 40’s. So I’ll get it real warmed up. Best I’ve seen the dash gauge even in summer is where it’s right between the 2 and 1 on the 210.

Thanks!!!

 

[Jeff Allan]

Got it on the scanner at my buddie’s place. The Jeep warmed up idle, reading 190. Reving gas got to 194 was the highest.

The temp coming out of the vents with heat on max is 135 F. I


I guess it’s a little low but is it bad for the engine?

 

[beaufrusetta]

Got it on the scanner at my buddie’s place. The Jeep warmed up idle, reading 190. Reving gas got to 194 was the highest.

The temp coming out of the vents with heat on max is 135 F. I


I guess it’s a little low but is it bad for the engine?

I would assume that it would read slightly higher than 195 after it's warmed up (then again, I live in AZ and it's hot as hell 6 months out of the year). The thermostat should open at 195, but then it's going to pass the cooler fluid back through - so I dunno - sounds like it might be normal? How cold is it outside where you are?

 

[Jeff Allan]

I would assume that it would read slightly higher than 195 after it's warmed up (then again, I live in AZ and it's hot as hell 6 months out of the year). The thermostat should open at 195, but then it's going to pass the cooler fluid back through - so I dunno - sounds like it might be normal? How cold is it outside where you are?

The Jeep was very warmed up, driving it for 20-25 minutes and it was reading 190 idling.

So I’m wondering if thermostat could still be at fault somehow.. I’d like it to be in normal range. Not sure what else to do.

 

[DSMITH]

my 05 Rubicon manual runs right around there since the radiator and hoses were replaced by the dealer. ticks up a bit higher with ac running or at long idles in traffic.
my son's 03 sport sits right at 210 but creeps higher at idle.
following this thread, as the 05 almost never gets to 210.

 

[RMETeeJay]

I think that's a little low. Even though it's not enough to throw a code, you may want to pull the thermostat to see if it's stuck open (the lower heat output also indicates a stuck open stat).

 

[beaufrusetta]

The Jeep was very warmed up, driving it for 20-25 minutes and it was reading 190 idling.

So I’m wondering if thermostat could still be at fault somehow.. I’d like it to be in normal range. Not sure what else to do.

I think that's a little low. Even though it's not enough to throw a code, you may want to pull the thermostat to see if it's stuck open (the lower heat output also indicates a stuck open stat).

Yup - that's what I'm thinking. And when mine stuck open...it was fairly new. For $12 and some wrenching time, you should be back in the game fairly quickly. Just don't over torque those t-stat housing bolts...I found out the hard way. LOL Luckily...t-stat housings are pretty cheap.

 

[KingCarGuyZ]

The Jeep was very warmed up, driving it for 20-25 minutes and it was reading 190 idling.

So I’m wondering if thermostat could still be at fault somehow.. I’d like it to be in normal range. Not sure what else to do.

Are you sure it’s not a 185 T-stat in there? Sounds exactly like what it would do. I have a 195 T-Stat and I will warm up to about 197 (on cool days) and stay there, just where the stat starts to open.

I would pull the T-Stat and replace it with a MOPAR/Stanly. There cheap enough and it’s not a bad job, make sure to get the 195*, drill a 1/4” bleed whole in the stat and check your coolant when your done, oh and torque it down pretty good. These housings like to leak.

on another note, what was the ambient temp (*F) / weather (raining, sunny, cloudy) if it’s cold and raining then mine will take forever to warm up and struggles to achieve 190*.

 

[bromel]

Yeah my money is on the shop used a 185 stat.

 

[MrMark52]

I agree on the 195 degree stat is the only stat that should be used.

But no one has suggested the temperature sending unit. Easy to replace, and not that expensive IIRC. And easy to check with a scanner.

Oreo had a 165 degree stat in it, and a missing CEL bulb when I bought it -

1. Replaced CEL bulb.
2. Scanner says engine not getting warm enough.
3. Take back to “mechanic” who guaranteed to get it to pass inspection - tell him to replace stat - he replaces sending unit, clears codes - tells me to drive it for a couple of days to allow readiness codes to set. cEL light come back on within a couple of hours.
4. Its easier to replace the stat myself than to take back to “mechanic”. Replace stat, clear codes, start and drive for about 5 trips.
5. Readiness codes quickly set - take back to “mechanic” to get inspected - PASS!

Moral of story - just because someone calls himself a mechanic doesn’t mean they know how to do anything but call himself a mechanic.

 

[KingCarGuyZ]

It could be the sending unit, but the fact that he’s not getting any heat makes me think the engine is actually cold and it’s the stat. Plus the stat is a lot more likely to be wrong than the sending unit is to break, but if the 195* Stat doesn’t work. That would be a good second place to look.

 

[MrMark52]

It could be the sending unit, but the fact that he’s not getting any heat makes me think the engine is actually cold and it’s the stat. Plus the stat is a lot more likely to be wrong than the sending unit is to break, but if the 195* Stat doesn’t work. That would be a good second place to look.

I agree with you, although when he said the heater gets hot but not as hot as previous TJ’s is somewhat subjective. For one, human‘s can not remian in contact with anything over 120-125 degrees F for any length of time without being burnt - so to be able to distinguish a temp difference of 10-20 degrees F at 185 x 195 degrees F is very, very subjective.
A scanned temp reading, or better yet - 15 minutes under the hood with a new $8.00 195 degree stat will end all doubt.