OVERHEATING, or close to it AGAIN

AdamIsAdam · **Posted:** Thu Aug 03, 2006 7:31 pm

There was much discussion on this topic. Let me start out by saying a
few things:
- everything is working (ie, fan, thermostat, pump, etc).
- there is no mud inside or outside my radiator as far as I can tell.

Here's what was just done within the last three weeks in terms of
service:

I completely flushed my system per the manual by removing the thermostat
and upper radiator hose, and running water through the system until it
ran clear. I flushed it for about 5 min. I did not open the block drain
plugs.

As long as I had the stuff apart, I replaced both radiator hoses and the
thermostat with OEM stuff.

Three weeks ago, before doing this, when it was 100* and humid as heck
here in NY, my temp gauge went up some. Went as high as 3/4 mark.

I have 55k and 3 years on my KJ, so this was the first service of the
cooling system.

Today was the first time I spent any time in the KJ during 103* and high
humidity and it again, went up as high as 3/4.

What happens:
While driving on the highway (or in town) without traffic, the AC on
full blast, the temp gauge creeps up. I does come down if I turn the AC off.

I'd like to hear from the folks from Arizon and other very hot places on this next point:

Prior to my KJ, I owned a Mercedes. That car would allow the temp gauge to wander up and down as it ran under such severe conditions. According to many experts on similar forums to this, anything not in the red was normal. Mercedes confirmed this. They said that this was normal for all cars, but that many Japanese and other makes "rig" the gauges to not show this variance just to avoid customers complaining. They said the Benz was more accurate.

I never saw this variance in my KJ before. Has anyone else experienced this?

I'm wondering if I should pull the radiator and have it professionally cleaned/rebuilt.

Thoughts?

2006KJSPORT4x4 · **Posted:** Thu Aug 03, 2006 7:38 pm

You could have an EGR valve issue....that also has caused the temp gauge to go up...at least for me and my Dodge avenger that was the case....Could there also be a possible water pump issue with your KJ? I know you do a lot of wheeling and have done some water fordging too...it might all be adding up perhaps???

KJ_Dave · **Posted:** Thu Aug 03, 2006 7:40 pm

I would check to see if your fan is working?

Jeepjeepster · **Posted:** Thu Aug 03, 2006 8:11 pm

He said the fan is working. Lets think about this alittle. If its overheating going down the Hw, then the fan has no roll in this. It will only overheat in traffic of when stopped if the fan is not working. Are you sure the "Radiator" is free of mud? This means taking a water hose, and spraying back into the radiator from the engine bay. If you spray the condensor from the front, that means the A/C will work really good. If you know the coolant is good, the stat is good, the radiator is not clogged(Outside and Inside), then that possibly leaves a bad water pump. I do not really know what it means for a water pump to go bad? Does this mean the impeller(or what ever it uses) has just worn away?

The libby has a really good cooling system. Not matter if it is 100 degrees, that needle should not move even with the A/C on. :wink:

AdamIsAdam · **Posted:** Thu Aug 03, 2006 8:18 pm

I'll replace the EGR. I'm not sure how that would effect it, but it's not a bad idea to do anyway.

Now, remember folks, I know what I'm doing and have been around the KJ VERY actively for years now. So, yes, my fan is working. And yes, I cleaned the radiator from behind and inside.

I'm thinking that maybe my water pump is not keeping up, although frankly it seems odd that it would be ok without the ac on (immediately). I'm wondering if my ac condensor is involved too, if perhaps its bearings are going and adding extra load when on.

Well, mainly I wanted to hear from those who have driven the KJ in extreme heat, to know if they've ever had the gauge wander.

Remember, I'm not actually overheating. The needle just walks up in this heat, regardless of highway or city driving. Turning the AC off means the cooling system can keep up. With it on, it's getting hot.

I'll try the EGR.

How does one test the water pump? (I'll check both my manuals on this too.)

Thanks for the ideas. Keep them coming.

DaveKJ02 · **Posted:** Thu Aug 03, 2006 8:30 pm

Deja Vu

*cough*pump*cough* Once mine hits dead center, it doesnt move to the point I wonder if it even works. I'm not in AZ, but I'm driving in the same temps you are!

2006KJSPORT4x4 · **Posted:** Thu Aug 03, 2006 8:31 pm

Well i'm in some extreme heat for the past month...record breaking 100* days here in Memphis especially with the heat index in the 105+* range...but anyway...check the A/C stuff really good again, there could be something up with it drawing more load on the engine thus causing it to run harder and then hotter...maybe check your seals to your engine and make sure there is no leaks or anything that haven't thrown a code yet...check the oil too and make sure it still looks clean too, hopefully it will not be anything too internal...

Off topic a little now:
My dodge ran great after the egr valve was replaced but about a month after there was catastrophic engine failure...when I broke down the motor with a friend we found that 2 of the valves for one of the pistons had snapped clean off...in fact they didn't even seem to make contact with the piston which was crazy odd...thus we found the final culprit to be, once we broke it completely down ( I had the 2.4L V6 Avenger ES), to be a bad water pump. Caused too much heat and eventually the 2 valves in the piston that was running richer then the other sheared right off....crazy stuff but that is what happened according to the mechanic we had check out our findings...

Cowcatcher · **Posted:** Thu Aug 03, 2006 9:58 pm

Some have similar complaints on the CRD side but mostly with towing. During the discussion though there has been comment on problems with the temp gauge that was apparently addressed with a TSB or recall. I don't know the number but I don't think it was CRD specific but KJ specific.

FreedomKJ · **Posted:** Thu Aug 03, 2006 10:22 pm

We've been in mostly 100+ temps since may and even crawling along wheeling with the A/C on my needle never passes center. There's definately something up.

Have you checked the oil for coolant? You might have an internal leak and not even know it.

You could have a clogged or corroded radiator core or a bad thermostat (I know you said it's working, but out of curosity how did you test it?)

The water pump impeller could be loose on the shaft, giving the appearance from the outside that the pump works fine, but it might not actually be performing properly.

Also don't rule out the possibility of a bad temperature sensor.

Jeepjeepster · **Posted:** Thu Aug 03, 2006 10:23 pm

I didnt know our gassers had an EGR? Where is it? What does it do?

2006KJSPORT4x4 · **Posted:** Thu Aug 03, 2006 10:56 pm

Exhaust Gas Recirculation Valve...

Check it out http://autorepair.about.com/od/generalinfo/l/bldef165.htm

FreeJeep · **Posted:** Thu Aug 03, 2006 11:00 pm

Had the exact same symptoms for over a year. Temp went up on highway with ac on. Finally gave in and took it to Jeep and guess what it was.....mud in between radiators :roll:

Had pressure washed it from inside, and outside in the past, but guess I didn't get it all. They pressure washed it out and no problem since. hmmm...

Gota luv the mud.

DonC

AdamIsAdam · **Posted:** Thu Aug 03, 2006 11:18 pm

Well, I just got a good look at the radiator and can see some mud down at the bottom left and right edges. I bet that's it. Bottom line is that when I need 100% capacity, I just don't have it.

I'll pull the fan shroud out tomorrow and get at the entire thing with a hose. I'm sure that will do it.

Oh, BTW, the EGR valve is located on the oil filler cap, poking out on the passenger side connected to a hose.

And my oil looks nice and clean, too.

Thanks for the thoughts. If I wasn't so tired and getting up at 5:45am, I'd pull it out now. But alas, tomorrow it's supposed to be a nice, cool 90* instead of this heat!

I'll post back tomorrow.

saxdogg · **Joined:** Fri Jun 02, 2006 7:26 pm **Posts:** 199

Thta's the PCV valve on the oil filler neck...from the SM:

The PCV system operates by engine intake manifold
vacuum. Filtered air is routed into the crankcase
through the air cleaner hose and crankcase breather(
s) (if used). The metered air, along with crankcase
vapors, are drawn through the PCV valve and into a
passage in the intake manifold. The PCV system
manages crankcase pressure and meters blow-by
gases to the intake system, reducing engine sludge
formation....just so there's no confusion!

You might go to a self-serve wash and pressure spray that sucker!!!

2006KJSPORT4x4 · **Posted:** Thu Aug 03, 2006 11:53 pm

Here is info on the PCV Valve....

http://autorepair.about.com/cs/generalinfo/l/bldef_621.htm

lilmatty · **Posted:** Fri Aug 04, 2006 10:42 am

Adam: I recently chased down the same problem. Did all the stuff you did except the EGR valve. Would even heat up on 80 degree days.

Then one day when it happened I popped the hood and noticed the engine wasn't hot. When it gets to 3/4 or even the red zone the heat should be blasting off the engine. That was a clue. I replaced the temp sending unit and all it back to normal. That is, staying pretty much in the middle of the dial.

AdamIsAdam · **Posted:** Fri Aug 04, 2006 11:23 am

Where is the temp sending unit?

I'm sure it'll be cured when I clean out the radiator better, but I'll keep an eye out for the sending unit anyway.

lilmatty · **Posted:** Fri Aug 04, 2006 11:29 am

On top of the engine kinda behind the water pump pulley. It won't look bad though. Got a replacement at NAPA. If you replace it make sure ahead of time you have a deep well socket that's deep enough. Mine weren't so I had to back to the store.

Recall I said the tell tale sign is that the engine itself was not hot even though the gauge said so.

I hope more cleaning of the radiator does it for you.

AdamIsAdam · **Posted:** Fri Aug 04, 2006 11:38 am

OK. tnx.

Out of curiosity, how can you tell the difference between 203* and 240* just by being near by (especially when it's 101* outside!)?

Jeepjeepster · **Posted:** Fri Aug 04, 2006 11:57 am

Just make sure there is no mud between the condensor and the radiator adam. Thats what it sounds like it is. If it was the sending unit, why would it go back down when the A/C was turned off? The sending unit is really easy to see. Its right where matty said it was, right infront of the intake manifold. If you have any problems finding it, ill take a pic for ya.

OVERHEATING, or close to it AGAIN

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