Your source, please.

 

here we go!

 

Most every 4.0 on the road

 

I'm convinced that 210* on the cluster gauge is as close to "correct" as my '93 4.0 will ever see. Four minutes driving to get there and then never moves until I turn it off.

Took some doing over the years to get there.

Please, massa, don't tell me that is not correct!!!

 

Is 209F or say 211F incorrect? What if the XJ gauge just had a "C" at one end and a "H" at the other end with no number in the middle of the gauge (like most cars).......what would the "correct" temp be? Why does the FSM never refer to a "correct" temp? If one installed a Mopar 180F stat purchased from a dealership (at least at one time) would the "correct" temp have changed. How is it possible to run 210, "correct" temp, in freezing cold weather running the heater. How is it possible to run 210, "correct" temp, in 3 digit ambient running a/c while stopped by traffic or boulders/rocks?

Most every 4.0 on the road doesn't overheat....but what/where is the source that says 210 is the "correct" temp?.....again, "correct" temp is never referenced in the FSM, that I'm aware of.

What/where is the source that says "it (meaning coolant temp, I presume) should not cycle"? How can coolant temp not "cycle"?......coolant temps (yes, the do vary/cycle) are determined by a bunch of components and all kinds of different driving conditions, so how can temps not cycle?. Again, what/where does it say "it (temp) should not cycle" and what/where does it say 210 is the "correct" temp?

I don't see the word "correct" anywhere on that dash gauge, not even at 210.

 

We're all searching for "correct". Some folks just have an opinion that if it is not running 210, doom and gloom will be upon us. How does the XJ make it through the winter months?......I know for a fact the ScanGauge says coolant never gets over the stat rating in winter running the heater. The fact is, the motor struggles to get to the stat rating in really cold weather but that doesn't mean doom and gloom because the motor won't actually reach the "correct" 210 temp.

 

When I typed that I was referring to 210 on the dash cluster, within a needle width or so. Certainly not a full hash mark above or below. Most everyone seems to say this is the way their 4.0's have operated since day one. Its dead center on the gauge. It's good advise for someone who is having trouble with coolant temperatures or those that think its high because every other car they've driven was 180F. I know that you like to run a 180F and that may be fine for you. I am not sure about the ScanGauge readings you're mentioning. Even on the coldest days during Colorado winters, my Jeep engine temp is right around 210 on the dash gauge.

 

I originally started to post with comments about the use of the word "correct" in this context but decided that I would let someone else do it. Reading through threads on the subject turn up those who are very nervous about overheating if their gauge gets up to 210*. Some aren't concerned about 220 or 230*.

I'm not sure what you mean by cycling as respects the dash gauge. Are you saying that you feel that it should fluctuate as the coolant temps and ambient temps fluctuate? Okay, that's a dumb question but I will leave it. My '93 gauge stopped cycling when I installed a 195* Stant Superstat about a year ago. Obviously if the gauge isn't fluctuating, the coolant temp at the sending unit (2 year old Mopar) isn't fluctuating. Ambient temps have varied from ~ 25* (I think) to ~102* with driving from extended idling in the take out line to 75 on the highway.

Is my current setup a freak occurrence or do others have a stable reading on the dash gauge under these conditions?

Edit: Note I was posting in response to djb383's posts.

 

The ScanGauge plugs into the ALDL under the dash and displays what the ECM is seeing/reading.....similar to the scan tool at the dealership being plugged into the ALDL port under the dash.

Factory dash gauges are "rigged" to point where the designers/engineers want them to point. As long as coolant temps r within predetermined parameters set by said designers/engineers, coolant temps r "normal".

One of those parameters is 160F.....when 160F coolant temp is reached within X amount of time after cold engine start-up, a normal warm-up cycle is counted by the ECM. If 160 is not reached in X amount of time, a CEL is set, at least on OBD-II systems. Another one of those parameters is 218F....the temp when the ECM turns on the efan. 218 is where the designers/engineers decided decided things r getting a little toasty, but not overheating, so that's the temp they want the efan on to cool things down a little.

Think about it this way.....if the dash gauge fluctuated between 160 and 218 a lot, the line of XJs (and other cars as well) at the dealership, along with their furious owners, would be a mile long.........and for no reason at all because the gauge is indicating normal parameters. To prevent the long lines at dealership service departments, designers/engineers "rig" temp gauges to point in a very narrow area on the gauge as long as temps remain within "normal" parameters. Jeep/Chrysler, for what ever reason decided to print the number 210 in the middle of the gauge. Most others just have a "C" and "H" on the gauge and the need points to the middle.....just like the XJ points to the middle.

Use a scan tool (or just about any after market temp gauge) to monitor temps and one will see how temps do "cycle" up/down in various different daily and seaonal driving conditions. The "rigged" factory dash gauge just sits there in the same spot as long as things remain within normal parameters that designers/engineers have predetermined.

 

^ dude just likes to argue

 

Been here over a year and just now figuring that out?

 

You are still confusing two different issues. They are saying exactly what I said.

 

Please refresh my memory as to what 2 different issues I'm confusing.....I'm old and forgetful......and at this point dazed and confused.

 

Ok, normal operating temp for the 4.0 is 210ish. I wish there were no numbers on my gauge, I like the Ford gauges where NORMAL is most of the needle sweep. My ZJ with the 4.0 runs between 208 to 215 depending on the type of driving, but once the needle creeps to the right of 210 I start to get paranoid for no real reason.

 

omg mine runs between 210 and the first hash to the left.