02 KJ Coolant Temp. Questions

Discussion in 'KJ General Discussion' started by KJCrazy, Feb 5, 2018.

  1. KJCrazy

    KJCrazy Full Access Member

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    When I first rebuilt my daughter's 02 KJ 3.7L V6 engine, I reinstalled the replacement fan that she had bought for it because here e-fan was shot before the rebuild.

    I also replaced the CTS after the build. At that time, the e-fan was kicking on and operating perfectly.

    I recently replaced the failing PCM and am now struggling with other parts. But that's all besides the point of this thread.

    When her KJ is running, it runs for about a half hour at normal temp, I THINK.

    Normal operating temp., I believe, is indicated by the dash temp. gauge reading with the needle at 12 O'clock. Is this true or is normal operating temp above the needle's center position. Here's why I ask...

    After a half hour of driving, the temp. will climb to the next line between 12 O'clock and the red line. It doesn't ever get hotter than that mark. I'm gonna call that mark "3/4 hot".

    It will get that warm, then cool down to "5/8 warm", then warm back up to 3/4, then cool back down to 5/8. Is there a concern here or is this normal for an '02 KJ 3.7L V6?

    At this time, I can't get the bleeder screw to turn. At all. I see coolant seeping from it, so I'm assuming air is bled from the system. No matter how much torque I put on that alan-head plug, I CANNOT get it to tighten.

    Here are my questions:
    1.) Why's my bleeder stuck and how do I unstick it?
    2.) Why's the e-fan not kicking on now? Relay?
    3.) What is the normal behavior of the temp. gauge needle during normal operation?

    Thanks for any help again. I'm not sorry for the long post because I want to thoroughly explain what's going on. I hang out ALOT on the WJ forum somewhere else and can't help folks that don't explain the situation....
     
  2. Tog

    Tog Full Access Member

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    My 04 always sits at about half on the gauge. Mins has both electric and mech fan not sure if this changes where the gauge will sit though.

    2004 3.7 limited
     
  3. Casey.N

    Casey.N Full Access Member

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    the temp should never exceed the 12oclock position, in my 02 for ex. it sound like there is air in the system causing it to run hotter than usual... for the bleeder screw id loosen it all the way and take that ***** out examine the threads and reinsert if the threads look good. if it where me id replsce the radiator too, its only 70-$90 i believe for a mopar one. the efan wont kick on until the motor gets pretty hot. for awhile i thought mine was broken too but you gatta get the ol girl pretty warm. except i have NEVER seen my temp gauge exceed the black line indicating 12 position. now that i think about it the temp is always slightly below the half way point, so you should never see that gauge exceed the half way point.
     
    Last edited: Feb 5, 2018
  4. tjkj2002

    tjkj2002 Full Access Member

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    They have a updated fan relay(located about 10" under the battery),get the one from MOPAR only,like $80 and has a huge heat sink on it.Also check the connector,common to melt when the relay starts going.

    The KJ's temp guage is a "dummy" guage.At halfway point your engine temp is between 178 degrees and 229 degrees.At the 3/4 mark your engine temp is between 230 degrees and 259 degrees.At full hot(red zone) your engine temp is 260+ degrees.

    The electric cooling fan(main cooling fan) turns on at 219 degrees(+/- a few degrees).The mechanical fan(if you have HD cooling) "locks up" at 230 degrees if you have the stock clutch.


    For the bleeder plug it must be cross threaded and the only fix is to replace the timing cover.Actually a very easy job but special tools are required(crank pulley puller) and very easy to get crap in the oil pan,kinda expansive part also which when I last looked was about $450.
     
  5. KJCrazy

    KJCrazy Full Access Member

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    When I did the rebuild, originally, I filled the coolant to full and got her running up to temp. at idle. I then replaced the cap on the coolant jug and tried cracking that bleeder for the first time. It took a HUGE amount of torque to get it to squeak open just enough to let air out. I could only get it to turn counter clockwise maybe an 1/8 of a turn....I mean it barely squeaked open....it's not like I got two or three turns out of it.

    I wonder how it got that way? I couldn't imagine, right now, the operation it would take to remove that thing......the bleeder screw I mean. I've had the timing cover off three times and am a pro at that.