Coolant Temperature Below 210

[Bowhunter]

Hello All,

Found threads about coolant at or above 210 but what about coolant temp below 210 like this picture.

This is a new to me jeep and I’m thinking the PO may have installed a lower than 210 thermostats. When I asked him he said he had changed the radiator and hoses years ago due to leaks but that was it.

My only concern is that the motor may be trying to burn a lot of unnecessary fuel in an attempt to get to 210 degrees which the cooling system won’t let it.

The pic is at idle, driving around town temp stays the same, at highway speeds temp increases a little bit but not quite to 210

Thanks to all the help this forum continues to give me!

 

[jws123]

I put a 180tstat in my old Tj to make it run cooler in summer never had a problem . I didn't like how hot it ran with stock tstat if you are concerned just change it cheap and easy to do.

 

[rouxbicon]

Hello All,

Found threads about coolant at or above 210 but what about coolant temp below 210 like this picture.

This is a new to me jeep and I’m thinking the PO may have installed a lower than 210 thermostats. When I asked him he said he had changed the radiator and hoses years ago due to leaks but that was it.

My only concern is that the motor may be trying to burn a lot of unnecessary fuel in an attempt to get to 210 degrees which the cooling system won’t let it.

The pic is at idle, driving around town temp stays the same, at highway speeds temp increases a little bit but not quite to 210

Thanks to all the help this forum continues to give me!

View attachment 175308

That does look a bit cooler than normal, and there’s not much that can make an engine run too cool besides an incorrect thermostat, or a correct but faulty thermostat. If it were mine, I would replace it with a new 195 deg Stant Superstat

 

[AjRagno]

This is where an infrared thermometer comes I handy. When I a similar issue with my TJ it turned out to be the coolant temp sensor.

 

[Nightmare9]

Code Reader will tell you the true temperature.
My thermostat failed in the 'open' position and my Jeep threw a P1281 Code - Engine Cold for too long

 

[CodaMan]

The temp sensors are not that accurate. Get a code reader to see what it really is under normal operating conditions. And for god's sake, don't put anything other than a 195* thermostat in it.

 

[CodaMan]

I put a 180tstat in my old Tj to make it run cooler in summer never had a problem . I didn't like how hot it ran with stock tstat if you are concerned just change it cheap and easy to do.

This is NOT recommended at all. The computer is programmed to run efficiently with a 195* thermostat. Anything else will affect air/fuel ratios.

 

[pagrey]

No code, no problem. If the engine is running cold you will get a check engine light.

 

[jjvw]

No code, no problem. If the engine is running cold you will get a check engine light.

That is an unusually low temperature that is worth investigating.

 

[CharlesHS]

As others have posted.... connect a scan tool and read what the real time coolant temperature is; the factory coolant temperature meter can be off a little.
After checking what the ECM is seeing for temperature; if the temperature is low... then the problem is either the thermostat is a lower rating, stuck open or the temperature sensor is not functioning properly.
When the ECM sees a lower temperature caused by a out of specifications thermostat or temperature sensor; the ECM may attempt to add more fuel thinking the engine is still warming up.

 

[TJRick]

This is NOT recommended at all. The computer is programmed to run efficiently with a 195* thermostat. Anything else will affect air/fuel ratios.

This. And believe it or not, it is actually better for your engine to run with a hotter thermostat. Ford has been running a 195 degree thermostat since the 1960s.

The name of the game is to get the engine to operating temperature as quickly as possible, and to run it as hot as possible. A cooler running engine accelerates wear.

It's also not a good idea to let a cold engine sit at idle to "warm up." It is far better to drive it easy until it gets to full operating temperature. A cold engine will warm up faster in one mile of driving that it would if you let it sit and idle for 10 minutes.

 

[pagrey]

That is an unusually low temperature that is worth investigating.

The computer will throw a code if it does not reach what it considers normal operating temperatures in a set time. So that means if there is no code thrown the engine is operating in a range the computer thinks is normal, which I also think is normal. The needle is basically straight up and actually touching the two in 210, it appears normal. A stuck thermostat will throw a code, the wrong temp thermostat will throw a code, that has happened to me. Since you quoted me, why do you feel it is worth investigating?

 

[Bloodlines33]

This is interesting. I am experiencing the same Bowhunter is. The PO replaced the radiator and some hoses so I've been under the impression that it's slightly cooler/more efficient = better. I'll pull out the digital thermometer and check actual engine temp.

Is there a location on the engine block I should be targeting to check the temp?

 

[pagrey]

Is there a location on the engine block I should be targeting to check the temp?

Nope, an external temperature will be practically useless information no matter where you point it.

 

[Bowhunter]

Been thinking about buying a code reader/scan tool to read things like temps in the motor/trans and check engine codes since I believe 97s don’t have the codes that show on the tachometer.

Is there a certain reader I should be looking at or they all the same?

 

[Nightmare9]

The Best one under $100 is the Blue Driver. It comes with the software.
https://www.amazon.com/dp/B00652G4TS/?tag=wranglerorg-20

I got a $27 one and it seems to work fine. If you just want to read and clear codes this one works.
https://www.amazon.com/gp/product/B078K54MT5/?tag=wranglerorg-20

I tried 3 different "Free" Apps to use it. Settled on the CarScanner

 

[Jerry Bransford]

Been thinking about buying a code reader/scan tool to read things like temps in the motor/trans and check engine codes since I believe 97s don’t have the codes that show on the tachometer.

Is there a certain reader I should be looking at or they all the same?

The 32RH does not have a transmission temperature sender so its temperature is not available unless you install your own sender in the pan or in the coolant lines.

Your 97 can display its own codes... https://www.allpar.com/fix/codes/index.html which basically says to quick-turn your ignition switch on-off-on three times within five seconds and then leave it in the on position to let the diagnostics run. Once complete any stored diagnostic trouble codes will begin displaying in the odometer display. At a minimum, if you did the key-sequence correctly, it will always at least show the '55' code which says no more codes follow.

 

[TJRick]

The 32RH does not have a transmission temperature sender so its temperature is not available unless you install your own sender in the pan or in the coolant lines.

Your 97 can display its own codes... https://www.allpar.com/fix/codes/index.html which basically says to quick-turn your ignition switch on-off-on three times within five seconds and then leave it in the on position to let the diagnostics run. Once complete any stored diagnostic trouble codes will begin displaying in the odometer display. At a minimum, if you did the key-sequence correctly, it will always at least show the '55' code which says no more codes follow.

That is neat feature. Do you know why that only works on the 1997 models?

If I were to swap a 1997 cluster into my 1998 model, would it do that?

 

[CodaMan]

That is neat feature. Do you know why that only works on the 1997 models?

If I were to swap a 1997 cluster into my 1998 model, would it do that?

It works on my '04

 

[Bowhunter]

The 32RH does not have a transmission temperature sender so its temperature is not available unless you install your own sender in the pan or in the coolant lines.

Your 97 can display its own codes... https://www.allpar.com/fix/codes/index.html which basically says to quick-turn your ignition switch on-off-on three times within five seconds and then leave it in the on position to let the diagnostics run. Once complete any stored diagnostic trouble codes will begin displaying in the odometer display. At a minimum, if you did the key-sequence correctly, it will always at least show the '55' code which says no more codes follow.

Thanks for the info Jerry. I’ll likely end up putting a temp gauge for the 32RH and a new cooler in like you did to monitor and keep the temps down while off-roading. Did you see much of a difference in trans temp when offroading/crawling vs just driving around town?