What Temp Is To Hot

[Melissa]

Okay, bare with me. What is the optium running and idling temp for a stock XJ? What I am trying to figure out is, I was in heavy stop and go traffic in a big city and I did not like how far my jeep heated up ( It made me really nervous ) On the open road my jeep runs at just below 210, but while in traffic it heated up to the white mark in front of the red zone. Should I be concerned? Suggestions?


I did read Mudderoy's thread on jeep 4.0L cooling system Re-Engineering. I have a brand new 180 thermostat, water pump, and thermostat housing, all put on about 3,000 miles ago. My jeep runs at the temp his does but it also just heated up to almost the same spot his did before he put his new 180 thermostat on. I have checked the coolant level, and checked for leaks, did not find anything.

[Mudderoy]

Have you replaced the radiator cap? Is it the correct PSI?

Did you put the high volume water pump ($150) from Hesco, or just a water pump from the parts store?

Have you replaced the mechanical fan clutch?

There is an article out there that describes how to wire a switch the electric fan so you can bypass the temp sensor and turn it on when you need extra cooling. This is good on the trail and stop and go traffic.

I need to do this to mine.

[Melissa]

Have you replaced the radiator cap? Is it the correct PSI?

Did you put the high volume water pump ($150) from Hesco, or just a water pump from the parts store?

Have you replaced the mechanical fan clutch?

There is an article out there that describes how to wire a switch the electric fan so you can bypass the temp sensor and turn it on when you need extra cooling. This is good on the trail and stop and go traffic.

I need to do this to mine.

Just a water pump from the parts store, have not replaced the mechanical fan clutch, Same radiator cap, but I do have a new one sitting around.

[Mudderoy]

I had to go back and look at my temp picture. Yeah that's too hot. Find you a local radiator shop and have them check your radiator.

Oh! You might want to change out the temp sensor first though.

[Melissa]

I had to go back and look at my temp picture. Yeah that's too hot. Find you a local radiator shop and have them check your radiator.

Oh! You might want to change out the temp sensor first though.

Oh that reminded me that it had a brand new temp sensor put on at the same time as the water pump and the other stuff. Should I replace the radiator cap and also have the radiator checked?

[Mudderoy]

Oh that reminded me that it had a brand new temp sensor put on at the same time as the water pump and the other stuff. Should I replace the radiator cap and also have the radiator checked?

If you have a way to make it get hot easily, then try the cap first. I don't think that is it, but having the radiator checked is going to be a lot more trouble and more expensive.

[Melissa]

I can only hope that maybe it might be the cap, I'd hate to have to put alot more money into it already after only 3,000 miles on the donor motor. In the mean time I'll start hunting around for a replacement radiator.

[Mudderoy]

Do you have a transmission cooler on your Jeep? It could be heat from the transmission that is causing the additional heat.

[Mudderoy]

You can check to see that the belt is tight.

I'd replace that fan clutch

If you haven't recently replaced the two hoses attached to the radiator, I would replace them, especially the bottom one.

oh, silly me, you did check the coolant level. The radiator is full right?

[Melissa]

That I don't know, How do I find out?

Both top and bottom radiator hoses are brand new, and yes the coolant was full.

What belt, the surp?

[Mudderoy]

You'll like this one.

When the engine is cold, just take the radiator cap off. Do you see fluid? If the answer is yes then it's full.

Have a look at your overflow bottle. If it is empty then your radiator isn't full.

The easiest way to fill your radiator to the brim is to fill the overflow bottle.

When the engine is off, and cooling it will pull coolant from the overflow bottle.

[Melissa]

You'll like this one.

When the engine is cold, just take the radiator cap off. Do you see fluid? If the answer is yes then it's full.

Have a look at your overflow bottle. If it is empty then your radiator isn't full.

The easiest way to fill your radiator to the brim is to fill the overflow bottle.

When the engine is off, and cooling it will pull coolant from the overflow bottle.

I didn't look at the overflow bottle when I checked the level in the radiator, I'll do that first thing in the morning and change the cap just for good measure.

[Mudderoy]

Yeah do that first. I forgot the basics. You do it so many times that when you are telling someone you tend to forget.

[muddeprived]

I discovered a neat way to reduce your temps. Hack into the heater hoses that go into the heater core and route them down under the jeep to the back and return to the engine bay. Clamp em good against the bottomside of the body, out of harm's way. I lost 8 degrees from this mod. :cheerleader:

Of course this is an idiotic and worthless mod. I only did it cuz i have my heater core INSIDE the jeep and just happened to discover that the motor runs cooler cuz of coolant cools off on it's LONG trip to the heater core.

[Mudderoy]

The pictures were awesome though!

[Melissa]

I discovered a neat way to reduce your temps. Hack into the heater hoses that go into the heater core and route them down under the jeep to the back and return to the engine bay. Clamp em good against the bottomside of the body, out of harm's way. I lost 8 degrees from this mod. :cheerleader:

Of course this is an idiotic and worthless mod. I only did it cuz i have my heater core INSIDE the jeep and just happened to discover that the motor runs cooler cuz of coolant cools off on it's LONG trip to the heater core.

I'm not that brave, I screw up some how. :eek:


I did check the overflow bottle this morning and it was full, so I guess now I will have the radiator checked.

[Mudderoy]

I'm not that brave, I screw up some how. :eek:


I did check the overflow bottle this morning and it was full, so I guess now I will have the radiator checked.

Have you done a system flush?

[Melissa]

Have you done a system flush?

Yes, when the donor motor was put in.

[Mudderoy]

Okay, bare with me. What is the optium running and idling temp for a stock XJ? What I am trying to figure out is, I was in heavy stop and go traffic in a big city and I did not like how far my jeep heated up ( It made me really nervous ) On the open road my jeep runs at just below 210, but while in traffic it heated up to the white mark in front of the red zone. Should I be concerned? Suggestions?


I did read Mudderoy's thread on jeep 4.0L cooling system Re-Engineering. I have a brand new 180 thermostat, water pump, and thermostat housing, all put on about 3,000 miles ago. My jeep runs at the temp his does but it also just heated up to almost the same spot his did before he put his new 180 thermostat on. I have checked the coolant level, and checked for leaks, did not find anything.

Was the A/C on or off? What speed were you going when it was running just below 210? About what was the outside air temp?

[muddeprived]

The pictures were awesome though!

pictures? where...what? how? when? why? I see no pictures......should i remedy that?

[Melissa]

Was the A/C on or off? What speed were you going when it was running just below 210? About what was the outside air temp?

A/C was off, speed at just below 210 was between 60 and 67 mph, outside temp was reading at 58 degrees. I went to Pendleton today, about 60 miles away and It ran even cooler, it was almost 60 outside and never got close to wanting to heat up past 210. I did smell anti freeze at one point, but everything is still full and I checked under the passenger matt for a wet spot from the heater core, but there was no wetness.

[Mudderoy]

You have a leak.

Did you fill the overflow bottle before the trip, and/or top off the radiator?

[Melissa]

You have a leak.

Did you fill the overflow bottle before the trip, and/or top off the radiator?

Yes now that i'm nervous about the temp, I did top off the radiator befor I took off yesterday.
As money is tight at the moment what kind of radiator should I get. I saw a all aluminum (Brand New) radiator on e-bay for $143.00 plus shipping, do I want one like that or should I just get the OEM one for $200.00. I would really like to get an oversized one, but I don't think I can afford to right now. Dam cows, just cost me $3,000 for power to start the irrigation season, and $2,000 for fertalizer. :(

[Mudderoy]

Yes now that i'm nervous about the temp, I did top off the radiator befor I took off yesterday.
As money is tight at the moment what kind of radiator should I get. I saw a all aluminum (Brand New) radiator on e-bay for $143.00 plus shipping, do I want one like that or should I just get the OEM one for $200.00. I would really like to get an oversized one, but I don't think I can afford to right now. Dam cows, just cost me $3,000 for power to start the irrigation season, and $2,000 for fertalizer. :(

Get you a black light from Wal-Mart (just the bulb) and then shine it around your engine bay looking for that florescent yellow to show up. This will help you determine where the leak is.

If it is the radiator leaking, that was the problem with mine. You can take out the radiator, take it to a radiator repair place. They'll check it over, tell you if it can be repaired and fix it. Mine was under $100 to repair.

It is possible it cannot be repaired.

I bought the 3 core, you can see it in my post. It was $160 at the time, I think I read someone recently bought one for $175.

I bought that one AND had my 2 core repaired. Now if something happens to the 3 core, I can put the 2 core in until I have it repaired or replaced.

Those radiator shops will remove and install the radiator for you but I didn't want to pay that extra money.

Oh and don't forget to check the electric fan. Make sure it is coming on with the A/C or when the temp goes above 210 (217 I think)

[Melissa]

I'll look into it and see what happens, thanks

[DETOURS]

Heres my take..........

You've got A/C condensor infront of your radiator, you 'possibly' also have a transmission cooler stacked in there as well (***most likely not from the factory with a D35 rear end, but still possible***)........you may be suffering from years of bug splatter, some mud possibly, any and all road crap that cold possibly have gotten lodged in there over the years.......plus maybe some deer fur???

Suggest: Go to the car wash....or use your own pressure washer, open the hood, and spray the heck out of your radiator as possible towards the 'front' of the vehical......if you can remove the fan shroud........even better! Spend some time doing this. (more than 3 minutes)

Loose 5 degrees: old hot rod trick.........remove your thermostat, drill '1' or a 'single' 1/8" hole through the outter portion of the thermostat, reinstall........typically you'll drop 5 degrees for free.

[Melissa]

Heres my take..........

You've got A/C condensor infront of your radiator, you 'possibly' also have a transmission cooler stacked in there as well (***most likely not from the factory with a D35 rear end, but still possible***)........you may be suffering from years of bug splatter, some mud possibly, any and all road crap that cold possibly have gotten lodged in there over the years.......plus maybe some deer fur???

Suggest: Go to the car wash....or use your own pressure washer, open the hood, and spray the heck out of your radiator as possible towards the 'front' of the vehical......if you can remove the fan shroud........even better! Spend some time doing this. (more than 3 minutes)

Loose 5 degrees: old hot rod trick.........remove your thermostat, drill '1' or a 'single' 1/8" hole through the outter portion of the thermostat, reinstall........typically you'll drop 5 degrees for free.


I do have a pressure washer, I will start there as I am keeping an eye out for a replacement radiator, Thanks Spanky;)

I will also keep in mind the old hot rod trick

Oh, and about the Deer fur, I am still picking it out everytime I wash my jeep :D

[BlueXJ]

I have read all 27 posts and no one mentioned the auxillary fan (the electric one). Mine came unplugged and the temps shot up. As soon as I plugged the sucker back in they came back to normal.

[DETOURS]

I do have a pressure washer, I will start there as I am keeping an eye out for a replacement radiator, Thanks Spanky;)

I will also keep in mind the old hot rod trick

Oh, and about the Deer fur, I am still picking it out everytime I wash my jeep :D

Pressure wash your keyboard while your at it......:rotfl2: (I saw that picture!)


Our bad, I myself assumed her fan had been checked........

[Melissa]

I'm pretty certain that the fan is running as it should, I'm so used to hearing it come on and off that I tune it out, but I will double check it as well.

Oh spanky about my keyboard.......................................... ......I did clean it up and my desk as well.

http://i730.photobucket.com/albums/ww305/melreese83/HPIM0473.jpg

http://i730.photobucket.com/albums/ww305/melreese83/HPIM0475.jpg

[DETOURS]

Very nice.......Thankyou! :thumbsup: