Overheating and not reaching optimal temp

[disneyridedoctor]

Hello,

Im a CRD noob. I've only had mine about 3 weeks now. So far I've discovered that I get about 30 mpg and I have way more power than any only Jeep I've had. So here's my problem:

Under load, ie going up a grade in 70-100° F weather with the AC running, I look down and see my temp gauge is in the red. I shut off the AC, took it out of OD to get the water flowing faster, and eventually pulled over and doused the radiator with cool water (that brought it down). Then about 5 miles later, the cycle begins again. When I shut it off, I could easily rotate the fan by hand and I never heard it howling under load so im led to believe that the fan clutch is bad. Agree?

Next, as I descended down the very same hill that I overheated on, under no load, my temp gauge failed to even reach 1/4. Is my thermostat bad or in the failed open position? Normally, it hovers right below the half mark. This is all in 80+° F weather.

First its too hot, then its too cold. Any ideas? My 07 Wrangler no matter what the condition is always straight up at the half position. Thinking back all my vehicles in the past maintained consistent temp.

Please help before my OCD takes over!!!!

 

[Billwill]

Hello,

Im a CRD noob. I've only had mine about 3 weeks now. So far I've discovered that I get about 30 mpg and I have way more power than any only Jeep I've had. So here's my problem:

Under load, ie going up a grade in 70-100° F weather with the AC running, I look down and see my temp gauge is in the red. I shut off the AC, took it out of OD to get the water flowing faster, and eventually pulled over and doused the radiator with cool water (that brought it down). Then about 5 miles later, the cycle begins again. When I shut it off, I could easily rotate the fan by hand and I never heard it howling under load so im led to believe that the fan clutch is bad. Agree?

Next, as I descended down the very same hill that I overheated on, under no load, my temp gauge failed to even reach 1/4. Is my thermostat bad or in the failed open position? Normally, it hovers right below the half mark. This is all in 80+° F weather.

First its too hot, then its too cold. Any ideas? My 07 Wrangler no matter what the condition is always straight up at the half position. Thinking back all my vehicles in the past maintained consistent temp.

Please help before my OCD takes over!!!!

Could be the fan clutch...most KJ owners replace it with the Hayden heavy duty clutch and some people replace the fan with the plastic fan from the gassers which has more fins.

Does your electric fan up front switch on? It is supposed to switch on if you have the AC on and also if things are getting hot.

Do you have any history of the water pump ever being replaced? Most guys replace the water pump at the time of the cam belt replacement which should happen at 100,000 miles.

The thermostats are known to give problems and hopefully your previous owner used the correct orange HOAT coolant in the cooling system and not any green stuff.

If you do not come right try the CRD section at L.O.S.T Jeeps Offical Web Site - For Jeep Owners for good CRD advice.

 

[disneyridedoctor]

The electric fan does kick on especially when the AC is on. What I don't hear is the mechanical fan engaging and "roaring" when its under load.

My rig has only 56,000 miles on it, although it is coming up on 8 years old. I have no idea on the service history as I got the Jeep from a second hand dealer. It does have the Orange coolant thank God.

Does the water pump have a clutch on it by the way? Never seen that....

 

[Mopars-Only]

No clutch on the water pump, so don't worry about that. The only failure you will ever see on a waterpump is a leak at the seal, dripping coolant on the ground. The fan clutch seems a likely culprit for the first issue, but then why it was running below the proper temp is likely due to the thermostat sticking in the open position. My CRD has just over 125K miles now and my thermostat has been perfect. My fan clutch did fail however, and the way I determined it was bad was to note it overheated slightly on a steep bridge I was climbling while pulling an enclosed trailer loaded with lumber. I had noticed my A/C seemed to be sub-par too, and the slight overheating on the bridge warned me to check my fans. I could spin the fan easily after shutting the engine off when I got home, so I replaced the fan clutch; not expensive from Jeep and very easy to change it out. It also fixed my A/C woes.
Now as to your temp gauge showing low temps you should consider the thermostat to be the problem. You can remove it and check it easily in a pot of water on a stove top, monitor the temp with a thermometer you can trust and watch the thermostat open and close as the temps change. I am a retired diesel truck mechanic, and I saw more than a few thermostats stick open and cause this problem. Ironically, you hear so many wanna-be mechanics blame the thermostat first for most all overheating problems, and in thirty some years I saw only one thermostat stick closed. It was an Isuzu car driven by the dispatchers, the spring broke and blocked the works so it could not possibly open. My experience is they rarely stick closed for what that is worth.
I would change that fan clutch that is not stiff when it is warmed up properly, and I would check the thermostat to see it is functioning as it should be.

good luck with it;
Jeff

 

[disneyridedoctor]

Thanks Jeff. I got my fan clutch delivered today. I will install and test it.

 

[marcgvky]

My fan was blown at 90K miles

I had the same issue. My truck was overheating in summer weather when the ram-air pressure from highway speeds was not present. I am not certain of the design of these fan clutches, but I noticed oil slung radially along the same plane as the fan/fan clutch. Upon inspection the fan could EASILY be spun by hand, while at operating temps, when the clutch should be interfering with ease-of-rotation to ensure proper CFM.

I replaced mine with a high-duty fan, because I do a lot of towing. But, it's a pain in the azz in the winter because the coolant always hovers somewhere below "normal operating".