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Jeep is running hotter but NOT overheating

ottexj2000

NAXJA Forum User
Location
Guilford, CT
Specs:
2000 w/ 223,000 (Changed Cylinder head october last year)
Water Pump 2 weeks old
Hoses good, Upper 2yrs old, lower 2 weeks old
Radiator seems fine. (3 core)
E-fan works, wired to switch
Mechanical Fan seems ok (have HD clutch to put on)


So recently I have noticed that my XJ has been running hoter than normal. I replace the Lower Radiator hose AND spring and the Water pump the beginning of the month. If I am on the highway it stays at 210 or just a hair under. But once I hit traffic it will climb to past 210. The E-fan always comes on when it should. I will also be adding an Aux trans cooler this week. My question could there still be air in the system? Got any tips for bleeding air outta the system? Thanks that covers all of it. Thanks for any help
 
The "open system" is self-burping the vast majority of times. Takes a few heat/cool cycles--hot expanded coolant moves into the recovery bottle, as the engine cools a vacuum is created and it sucks coolant back in.

However, you can park with a nose up attitude, trying to get the radiator cap at the highest elevation of the entire cooling system, then warm the engine up fully and let it cool down.

Do you have a proper late Spring--early Fall coolant mix of 30 ethylene glycol/70 distilled water? When was the radiator cap new? Is the cap a 16 lb or an OEM 13 lb?
 
I do not have the 30/70 mix. The radiator cap isnt new but I think I will just go get a new one. I am going to flush out my heater and put the HD fan clutch on.
 
New cap is a good idea. They are about $5.00 and are OFTEN overlooked. I just replaced one on a Camry that had 210k. Unreal.

How much past 210 does the gauge go?? Devil is in the details.

Also might be a good idea to verify your actual temperature by shooting an infrared thermometer at the thermostat housing. Sometimes, there is a little inaccuracy between the sending unit and the gauge.

Good luck.
 
HD fan clutch can be a band aid to the real problem. I probably wouldn't use that unless you do a lot of hill climbs and/or towing AND you have a properly functioning system.
 
Not saying that the cap "isnt" faulty but .......

Its now summer ... and your running temps are higher ... and you didnt mention what the temp is - over 210' either ... ;)

That would indicate that some failing part that could manage the job in winter... is now struggling with the hotter temps.

The cooling ability of the radiator would be my first concern under the given circumstances and info. ... and maybe a thermostat thats not opening properly.

Clean/flush rad, check for blocked fins etc - replace t'stat ... use a 195' until you isolate the overheating cause.

Also the cooling ability of the liquid in the radiator ... As joe_peters suggested - 30/70 ethgly/water ... Helps keep things a bit more stable in hotter weather ... But using it is dependant on your daytime minimum temps.

50/50 is "new world order", global car drivel, average mix for all locations. ( just my opinion of course ... ;):D ) .... And as with tyre pressures and engine oils or anything else ... Use what you need for your driving conditions.

Radiator caps or anything else pressure related would have been causing a problem prior ... unless it has only recently failed .... Generally, things dont just suddenly fail ... they wear out over time due to use/neglect.

Pulling more air with a better fan is a nescessity on the mediocre factory cooling system ... and fitting a better fan is only a bandaid measure ... If you dont fix the underlying fault.
 
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Well when it does run hot it doesnt get past 220 becasue the E-fan kicks in. My thermostat is 3 months old, 195' with a 1/8" hole drilled in it to help bleed the system.

My Jeep ran perfectly temp wise until July 4th when the lower raditor hose started to leak. With the help of a buddy who is a mechanic we bleed at the air out of the coolant system about a week ago and it ran great temp was 205' and would go just a hair past 210 in traffic. That was with 50/50 mix. What I am going to do tomorrow is replace the radiator cap and flush out my heater core with a garden hose. If that doesnt help then I will switch to the 30/70 mix. Does any one have a tip for making this mix. I was thinking of using a half a gallon of water and half a gallon of coolant.
 
Most would probably say your XJ is running normally ... Its certainly performing as per the FSM.

Another flush is probably a good idea ... Might have some gunk in there that was dislodged when you replaced the bottom hose.

As for mixing ratios ..... probably need to suss out the stuff available.

Theres three main components of the wet stuff that goes in the radiator ...

Eth Gly ... to prevent freezing ...
It also provides a higher boil temp - and so it should ... since it raises the engine running temp ... and it doesnt shed heat in the radiator as effectively as water.

Water ... For cooling.

Additives for anti-corrosion.

Eth-Gly doesnt break down over time ... but the additives do.


Down here I normally buy "Type B" premix ... Has hardly any eth-gly but still has all the additives ... so they reckon :rolleyes:

In addition to the "Type A" 50/50 premixes that you fellas have ... we also have "Type A" premixes of 30/70 where presumably, the manufacturer has watered down the eth-gly ... but not the additives.

A "Type A" concentrate, diluted ... not only dilutes the eth-gly but also the additives ... just something to consider if its going to be left in the radiator for considerable time periods without changing.
 
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