overheating

JL Rockies · **Posted:** Fri Jun 03, 2011 6:38 pm

I pulled the relay for the viscous heater and the fuel heater just now. I'll see what happens and junk.

Wobbly · **Posted:** Fri Jun 03, 2011 8:38 pm

Pulling the relay for the viscous heater won't disable it if the clutch has insufficient clearance to disengage.

JL Rockies · **Posted:** Sat Jun 04, 2011 1:59 am

Well, it's going to be the new owners problem I guess.

DOC4444 · **Posted:** Sat Jun 04, 2011 8:43 am

It is easy to see if you have been successful in disabling the VH. The center section of the pulley will be stationary.

DOC

JL Rockies · **Posted:** Sat Jun 04, 2011 1:33 pm

I will look at that then.

retmil46 · **Posted:** Sat Jun 04, 2011 3:25 pm

If you've troubleshot the cooling system to hell and back, found nothing wrong, and the beast still overheats, maybe the problem isn't the cooling system - perhaps something else on the vehicle is fubar and making the engine work harder than necessary for a given set of conditions.

Is the front end alignment REALLY correct? I've heard of several people discovering that their front end alignment had been off ever since having the stealership do the LBJ recall. I opted for the Moog solution, but found out recently the hard way my front end alignment was off.

Started hearing what faintly sounded like tire noise on a trip back to NC in Jan. Early Feb had it checked out at a local garage that said alignment and shocks were fine (note - that was at 53K miles with original factory shocks - yeah, I know...). Well, 3 months and a new set of tires later, discovered that those guys couldn't align tab A with slot B. In the meantime, even in spring weather here in SA, I noticed that the electric fan was working overtime whenever the A/C was on, and the aux tranny cooler was hot enough to burn after a 20 mile run on the interstate.

After noticing that the front tires looked as if someone had taken a disc grinder to the outside 1" of the tread, I took it to another shop that was highly recommended locally, had the tires rotated and balanced and the front end alignment redone. Mechanic's comment was "That other place may have checked the alignment, but they sure as hell didn't ADJUST anything - it was WAY off!". Difference was immediate - drove and handled like a new vehicle, fuel mileage shot up noticeably on the first 1/2 tank, electric fan was no longer working overtime (this with the metal mechanical fan still in place) and the tranny ran noticeably cooler as well. I also had to relearn when to put on the brakes as this thing now wanted to roll like it was on ball bearings.

As far as the shocks and struts - after doing some further testing, I've come to agree with the conventional wisdom - if you're past 40K miles and still have the original factory shocks, get them replaced NOW. I'm convinced that these worn-out shocks had a good bit to do with the front end alignment being off. And causing another problem with the rear suspension...

My tire noise I first noted in Jan kept getting louder, until when I got it up to highway speeds it sounded as if a tire was seriously out of balance or out of round, or the rear diff was trying to eat itself - but only noise, no vibration. Front end alignment, new tires, pulling the front driveshaft - noise was still there. Tests in the FSM pointed to the rear diff or driveshaft - but again no vibration or other problems. Turns out the worn out shocks were responsible for this noise as well.

The rear upper suspension arm (looks like a boomerang) attaches to the rear diff with a balljoint (Chrysler balljoint should have spelled "problem" right there) at the point of the "V", and at the ends of the arms with two rubber bushings to the body. The worn out shocks had put enough stress on the rubber bushings that they had stretched against the rubber and allowed the metal sleeves to move upwards such that they were now in direct contact with the body - almost direct metal-to-metal contact sound path from the diff to the cabin - I was simply hearing amplified normal drivetrain noise.

The out-of-kilter rear suspension arm was also throwing off the rear end alignment and tracking as well, adding to the engine's work load.

Other things to consider - running larger than normal tires? Changed the gearing on the rear end? Lifted the vehicle and changed the driveshaft geometry? Front driveshaft or CV joint getting old and binding up? Look at anything that would noticeably increase the engine's workload.

An aside - since most of the above happened, I installed the 11 bladed nylon fan from the gasser version - I'd already installed a Hayden clutch last year - that fan moves a crapload of air - I don't think I've heard that aux electric fan kick in yet - after a 20 mile run on the interstate and still having the A/C going full tilt, as soon as I pull off and come to the first stoplight, the coolant temp is already edging back down below the 12 o'clock position - no small feat on a 95 F SA day. Ranger1 recently did the same mod, and reported that after a hard run his EGT cooldown time to 400 F had been cut in half. I'm actually having to turn down the A/C on the drive to work now after about 10 minutes.

And yes, FYI the nylon fan is a direct bolt-up to our fan clutch - just take off the metal one, and bolt on the nylon version.

JL Rockies · **Posted:** Sat Jun 04, 2011 4:02 pm

My alignment is fine and has been fine since 2007. New tires installed Feb and alignment done then.

I looked at the viscous deal and it's not turning. It's a beautiful day in UT, low 70's and sunshiney. I took the KJ out on the freeway over "Point of the Mountain" which is a very minor grade, not even enough to warrant a trucker low gear warning sign. With the AC on and the viscous and the fuel heater relays unplugged, the temp gauge quickly shot up to the 3/4 mark into Utah County and the first red line back into Salt Lake County. This is with the cruise control set for 65 mph. The only impact the relays seemed to have had was the temp dropped back to normal very quickly once I was flat. This inspires no confidence however since it will soon be in 90's and many of the grades I drive over are much longer and steeper. The good news is, at least this season I now have another vehicle to pick up the KJ's slack. Like I said, this KJ is an awesome winter vehicle.

Wobbly · **Posted:** Sat Jun 04, 2011 5:22 pm

DOC4444 wrote:

It is easy to see if you have been successful in disabling the VH. The center section of the pulley will be stationary.

DOC

Good point and it's visible without removing anything.

Wobbly · **Posted:** Sat Jun 04, 2011 5:27 pm

JL Rockies wrote:

My alignment is fine and has been fine since 2007. New tires installed Feb and alignment done then.

I looked at the viscous deal and it's not turning. It's a beautiful day in UT, low 70's and sunshiney. I took the KJ out on the freeway over "Point of the Mountain" which is a very minor grade, not even enough to warrant a trucker low gear warning sign. With the AC on and the viscous and the fuel heater relays unplugged, the temp gauge quickly shot up to the 3/4 mark into Utah County and the first red line back into Salt Lake County. This is with the cruise control set for 65 mph. The only impact the relays seemed to have had was the temp dropped back to normal very quickly once I was flat. This inspires no confidence however since it will soon be in 90's and many of the grades I drive over are much longer and steeper. The good news is, at least this season I now have another vehicle to pick up the KJ's slack. Like I said, this KJ is an awesome winter vehicle.

First step is to make sure that the gauge reading is roughly accurate.

JL Rockies · **Posted:** Sun Jun 05, 2011 12:21 am

Is that really important? If the KJ thinks the gauge is accurate and starts cutting off the AC and fuel when the needle gets into the red, you got the whole broken clock being right thing going on. When the dealer looked at mine in 2009, they checked to see if the gauge had been updated... it had. When Yellocoyote was driving my KJ around Pastafari, she had to keep it in 4 Lo and the heat on. When I lifted the hood after we stopped, you could've cooked an egg on any given part of that engine bay.

The reality is a percentage of these KJs behave like this and no one knows how to fix it. There are threads as old as the US CRD posted on these forums none of which offered any verified solutions.

ATXKJ · **Posted:** Sun Jun 05, 2011 8:43 am

JL - as part of 'I've replaced everything'
- did you actually verify that the mechanical fan turns on?

Admittedly the only time mine had a problem was climbing a mountain pass once - however I've climbed a lot of them without problems.
My purpose in buying the diesel was to have something that could drive to Colorado and still fit on mountain trails - My break in trip for the CRD was to drive from Austin to Pike's Peak and back, so getting hot once was a concern - but not a big deal and even at that, I've never heard the mechanical fan turn on. It should be noisy and obvious.
Some of the first posts on overheating were KeighJeigh and his troubleshooting - the issue was the fan not turning on and the fix was the clutch replacement.

so lots of discussions - but 2 basics
1) make sure you don't have anything adding heat - alignments, dragging brakes,viscous heaters ect.
2) make sure the mechanical fan turns on.

(as part of not adding heat - unplug the Edge for a test run up the mountain and see if that changes)
and if you have questions about the fan turning on
Kap's FFM will remove all doubt
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=51618&hilit=fixed+fan

DOC4444 · **Posted:** Sun Jun 05, 2011 8:42 pm

When we tow a 5K pound trailer up a long highway grade in 90+ degree temps, our temp gauge that has been recalibrated with the TSB, pegs within a minute. Despite replacing the fan clutch with another OEM fan clutch, we have never heard it engage. We used to have a diesel Suburban and when the fan clutch engaged it sounded like a small hurricane under the hood. I am told that when the KJ CRD fan clutch engages, it sounds similar.

So, I believe your problem is simple and the same as ours, that needed increased airflow through the radiator is not happening. I have purchased a Hayden "Extreme Duty" fan clutch, but do not plan to install it until I do the timing belt/etc. This won't be for awhile, so I won't be able to offer info soon. However, it is supposed to engage between 170 and 190 degrees. (The OEM does not engage until 215-225.)

You could go with a fixed fan like Kap, but I believe that will both hurt mileage and keep the temp down which is also not good for several reasons.

The Hayden from O'Reilly is less than half the price I paid for a new OEM. It is only about $60. If you can find my old thread about how to secure the fan pulley to easily break the nut free and remove the shroud w/o cutting anything, it won't be hard at all to install.

(People keep saying the worst part of the timing belt job is removing the fan clutch.)

I really think the Hayden will solve your problem.

DOC

eleonard3012 · **Posted:** Mon Jun 06, 2011 2:06 pm

My hydraulic fan spins all the time, but not with any gusto. At operating temp the fan will turn at idle. But I don't think I have ever heard a hurricane under my hood, the electric fan makes some noise and is loud but as for the mechanical fan it is hard to tell. I plan on going up some mountain road getting the temp up to 3/4 soon to check if my temp sender is reading correct I will check the fan as well. If I am at 3/4 and at idle what should I see/hear/feel that is different? Will I be able to feel the air moving over the top of the engine? Thanks

papaindigo · **Posted:** Mon Jun 06, 2011 2:32 pm

The electric fan just behind the grill is primarily for AC operation and doesn't make much noise at least when driving (at idle you can hear it). The mechanical fan between the engine and the intercooler inside the fan shroud is driven directly by the engine BUT it only engages when the viscous clutch thermostat reaches a preset temperature at which point the clutch engages and the fan spins at some set ratio to engine speed. With the clutch disengaged I would not be surprised if that fan spun slowly simply due to air flow across the fan blades and/or a bit of residual drag on the clutch but it's not "doing" anything for cooling. The clutch is a known weak point in any fan of this type not just Jeep or Chrysler; when the clutch fails the fan simply won't engage. IMHO this is a designer's attempt to make engines "guieter" that's about as smart as replacing timing chains with rubber band belts or putting nylon teeth pads on steel timing gears to do the same thing but no one asked me.

See page 2 of viewtopic.php?f=5&t=51618&hilit=flex or the FSM for an on vehicle test of the fan clutch which boils down to block or partially block the radiator to get the vehicle up to ca. 3/4 on the temp gauge and see if the fan engages. Trust me if the fan engages you will have absolutely no doubt as it will jump from idleing along to sounding like it's trying to power a wind tunnel. If it doesn't engage fixes include: 1) a new OEM fan (modestly expensive and still subject to failure); 2) a new OEM fan clutch (ditto); 3) an Hayden heavy duty fan clutch (relatively inexpensive and engages at a lower temperature); or 4) kap's fixed fan at viewtopic.php?f=5&t=51618&hilit=flex. If you elect to stay with a clutch fan it's said that the nylon 12 fan on the gas KJ fits just fine and moves more air when it engages which is a good thing.

arengant · **Posted:** Mon Jun 06, 2011 2:52 pm

If the Hayden engages at 170-190 degrees, won’t this hurt performance in winter months? I am still trying to get my CRD up to temp.

papaindigo · **Posted:** Mon Jun 06, 2011 4:12 pm

According to the Hayden literature their clutches engage based on radiator air temp, logical, which they say is about 30 degrees below coolant temp so you should be fine in the winter especially if your tstat is working ok. as our normal operating temp will be ca. 176 or 195 if you have Kaps modified tstat and the Hayden shouldn't engage until a coolant temp on the order of 200+

JL Rockies · **Posted:** Mon Jun 06, 2011 4:22 pm

Among the things I replaced when doing the timing belt was the fan clutch with a new OEM. I was really hoping the new clutch pump and t-stat would make a difference but no... no it didn't. I think the best solution is to route the ducts outside so you can blast the heat and not die a little inside on each summer road trip.

turbobill · **Posted:** Mon Jun 06, 2011 6:24 pm

Checking engine temp gauge calibration is easy enough, then you KNOW if you are hot when the gauge says you are. you can use a laser temp gauge and shoot the top of the thermostat housing, use a thermocouple held tightly to the thermostat housing ( my way) and / or use a kitchen thermometer to measure the temperature of the air moving through the radiator (I also did this). I quickly found that my temp gauge was calibrated for gas rather than diesel. This was a common problem for a large number of 2005's coming from the factory. When i finally got my Jeep to hit red marks I got the 5 chimes warning that I was reducing performance (first step of protection for the engine), then in a minute or so the fan kicked in cooling everything back off to normal.

I also had a recent problem with running warmer that was due to over fueling caused by a split in the turbo return hose. My sensitive temp gauge picked up the higher operating temp ( 210 to 220). Hope you find your problem soon, but it sure sounds like you do not have an overtemp problem, just a temp cgauge calibration problem. I have decided to leave mine in the "more sensitive" state since I picked up the over fueling problem with operating temp up tick.

JL Rockies · **Posted:** Mon Jun 06, 2011 7:50 pm

yeah...as I stated, I can cook an egg on any given part of the engine bay... the needle is in the red because schizz is really really hot. I don't need a shark with a frickin' laser attached to it's head to know things are awry. I am interested in this hose thing though.

ATXKJ · **Posted:** Mon Jun 06, 2011 9:49 pm

JL- I understand you changed the fan clutch - my question is - did you test it to see if it worked?
(if you don't understand my logic - talk to tjkj about new parts that don't work)

if it does work - another test - pressure check the radiator/cooling system - is it leaking?

I'd figure any air bubbles are gone by now -and I don't know if there good test.

overheating

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