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Cooling, running cold mystery to me...

xjwisconsin

xjwisconsin

NAXJA Forum User
Location
sturgeon bay, wisconsin
98, 4.0, ax15, np231.

Engine has been running cold for as long as I can remember. Consistently keeps the needle on the hash below 210. Does not reach 210 summer, or now with 10 degree weather. Decided to investigate today. Tightened the belt as it was a bit loose. Pulled the thermostat and replaced with new that was verified to be working. Replaced the radiator cap, 16lb. Appear to be getting no flow through the upper or lower radiator hose. Let idle in the driveway for a half hour, temp sitting on hash below 210. Then took half hour drive through town and on highway, needle would get to just below 210, then return to the lower hash.

Bad water pump? If so wouldn't it be overheating?

Any insight appreciated. I have searched but found nothing like this?
 
Ummm, sounds like just about perfect to me. Why do you think you have a problem. Just below 210...that ain't broke.

If you don't think coolant is flowing through upper hose...take it off, see what happens. If it wasn't circulating (water pump malfunction) it would be overheating, as you said. Your sensor/sender or gauge could be wrong too. I'd leave it be unless you're losing coolant or have other problems.
 
I have a 2001 that also runs around the line left of 210 or even a little below that. I have a 195 thermostat so I assume its sticking open. Still makes good heat so I'm not real worried about it. I have upgraded everything in the cooling system and it always runs a little left of 210 in the summer.
 
yeah, if it's holding at 195 or a little higher fuhgeddaboutit.

Is it coming up to temp quickly, even in cold weather? If answer to that is "yes" then you're fine.

BTW mine would always run 210 or a little higher until my rad sprang a leak, now with a new rad it runs at 195-200 most of the time. Be happy!
 
I suppose your suggestion on the hose is a valid one. Will try that tomorrow.
My heat in cab is less than stellar, fairly certain it is a clogged core. Was thinking that the thermostat was stuck, and that the engine was not getting up to full operating range. I became concerned when I could feel no noticeable flow in the radiator hoses.

I forgot to mention I am running a 3 row all metal radiator from CSF.

When I was running this afternoon it was with the e fan disconnected.
 
xjwisconsin said:
When I was running this afternoon it was with the e fan disconnected.
Click to expand...

You did not have the e-fan running all the time Did you?

The winter I spent in Iowa, my XJ would run below the 210* mark all the time unless I was sitting in traffic then it would get to or just above 210*. Bear in mind there is no mechanical fan on my XJ and the electric fans come on only when the temperature get to about 213*. With just the in cab heater turned on I would see a drop in temperature especially if it is turned up high. At highway speeds it would be about 195 or below.

What brand thermostat did you use? I use only the OEM unit from the Jeep/Chrysler dealer. If the heat in the cabin is not hot then you should take a look to see why it is not. Other than that, I would not sweat it especially if the ambient temperature in below 40 degrees.
 
I suppose that a problem with running cool would be less than great heat in the cab. But seriously, 195 is perfect IMO. Feel the two heater hoses. Are they the same temp? Are they close to the same temps as the upper hose. If not, the flow through your core is restricted.

Flushing the core independently is fairly easy...and decisive. If the hose flows through, it's all good. If not....

Is your upper hose...er...flaccid.

And BTW taking off the upper hose while the truck is running...I was kind of kidding as you'll spew coolant all over....and certainly not when it's hot.
 
I just figured Id fire it at the snow on the driveway to help melt it. HAHA! Sorry my wit does not a translate to written word some times...
I will do the old hose check again tomorrow and see if I can figure anything out.

Thanks for all the input guys.

I forgot to add/ thermo and cap are Stant. Boiled up some water and placed both the old and new thermostats in the water. Both opened with no problems. Put the new one in as I had no idea the brand of the old. Going to keep it as a spare. Have been running the e fan in its stock form. Removed it today to get at the tension bolt. I am planning on reinstalling it tomorrow.
 
Last edited:
Why in the world do you ask about running cold when it's running at 190 when your outside air temp is probably below zero?????

The heater core run on low heat into the cabin is all the engine requires to maintain temp when it's that cold.

When it's below zero my '01 runs a needle width below where it runs when the temp is above 50 - on the interstate pulling power working to stir the molasses in the differentials.
 
Mainly I was hoping in vain that part of my interior cabin low temperature was due to the engine running colder than normal... Not due to what is most likely a fairly plugged up heater core. I flushed the core last winter I think... The heat just does not seem to be where it should, could be.
 
I had the understanding that a clogged heater core would cause my interior air temp to be reduced, or cold. I am getting heat in the cab, but I literally let the rig idle in the driveway for almost 40 min the other day in 15 degree weather and it was barely warm inside. I remember when I first got the old boy I could wear a t shirt in sub zero weather.
Today I let the rig idle out front for twenty minutes, drove about 5 miles around town. stopped to talk to a buddy for ten min. Restarted the rig. Temp gauge was showing around 130-140...
When I was driving it this afternoon when I was driving with no interior heat going for most of the half hour. I turn the defrost on from time to time to combat my own breathing, but the needle on the temp gauge would only drop a minimal amount when the defrost was applied at full speed.
I am going to pick up a blower motor from a guy this week. I believe mine is going down, as I lost speeds 1-3 last week.
 
Clogged heater cores do not make engines run hot, especially in the cold dead of winter, they just don't heat well.

Every XJ I have had, including the current one which has all Efans is slow to come up to temp in the winter and to warm the interior. I don't even turn on the efans and the engine temp doesn't come up to 210 for a good 10 minutes of drive time. About the time I'm getting to work, the engine is reaching temp.

When I drove to La Crosse last weekend I watched the needle cycle between 200 and 210 which is very unusual for my 2001. I actually turned the heat down in the cabin to try and put some back in the engine.

Sigh, It's that time of year again, put a slice of cardboard on the grille and tie it on with tie wraps... That reminds me. Note to self - put cardboard on the Jeep grille.

Edit: Fan Speeds-replace fan resistor.

-Ron
 
Just a shot in the dark

Ive also done this...WB9YZU...to get my e-fan to come on

put cardboard on the Jeep grille.
 
Thanks for the input guys.

Yes some of the interior heat issue is probably related to the old squirrel cage taking a dump.
I have never had to run cardboard or the like, but I am thinking of trying it.
Tomorrows tasks will be -
Verify e fan operation by jumping it off of the battery.
Verify mech fan operation (feel its good as I get that beast roar on cold start)
If e fan is in-op, figure I will just dump it for now with the current weather.
Thursday I pick up the blower so we will see if that makes a difference.
I know its weird, but I just feel odd that all these other rigs with the same set up are hitting the 210 mark summer and winter and I am not?
 
Have you verified that your temp gauge is working correctly and your coolant temp is actually at temperature? I'd really start there.
 
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