engine heats up when towing?

bigbillyboy · **Joined:** Wed Jun 16, 2010 6:10 pm **Posts:** 75

Hi all. I've had my CRD for two great years, and recently bought a ski boat. The boat on the trailers weighs 4300 lbs. I took it out last week, and was very surprised at how well the CRD pulled it around. I can tell that the trailer brakes help immensely. My question is that on the way back, which was mostly uphill, and included a couple of 2 mile long grades, the CRD heated up to about the 3/4 mark, at which point I crested the hill and it cooled right down. It was 85 degrees.

I have the GDE ECO tune and installed the inline thermostat housing last winter, and have never had the temp move off the "one notch to the left of half" since I installed the thermostat.

For those of you that tow and have pulled hills, is it normal for the temp to jump up to the 3/4 mark, and should I be worried?

Thanks,
Jason

spitfire36o · **Posted:** Wed Jun 27, 2012 7:21 pm

Check the fan clutch. It may be on its way out and not fully engaging to offer the needed cooling when under load. Also if the transmission was hunting for gears a lot, the added transmission heat may have been transferred to the engine. Were you towing with OD on or off?

Joe Romas · **Posted:** Wed Jun 27, 2012 7:37 pm

First take the inline thermostat off :banghead:

A lot of the 05 fan clutches were bad from the get go and caused overheating when any extra load was put on them.
Then see this thread with what you need to do. It's been very hot heare since right after I replaced these parts on mine and the AC has never been colder :BANANA:

viewtopic.php?f=5&t=69145&p=739662#p739662

naturist · **Posted:** Wed Jun 27, 2012 7:46 pm

The stock fan clutch is a piece of junk. Has been from the get go.

Lots of people experience the same thing: gauge never budges off just left of center, until you tow, uphill, in 80+ weather.

The inline thermostat is not your friend under those conditions. The stock one is designed to circulate water no matter what, and to keep the engine temperature as uniform as possible throughout the block and head. I think the inline one is asking for cracked head and/or block, but what do I know?

Well, one thing I do know, the stock fan clutch is extremely fragile, wears out very quickly, and engages in the first place way too late. Spring for a Hayden heavy duty, the one that kicks in at 170˚F.

DOC4444 · **Posted:** Wed Jun 27, 2012 10:22 pm

When you install the Hayden clutch and the plastic (gas) fan, reinstall the inline thermostat, tow and let us know. I have all the stuff to do this, just no time.

DOC

geordi · **Posted:** Wed Jun 27, 2012 11:36 pm

naturist wrote:

The stock fan clutch is a piece of junk. Has been from the get go.

Lots of people experience the same thing: gauge never budges off just left of center, until you tow, uphill, in 80+ weather.

The inline thermostat is not your friend under those conditions. The stock one is designed to circulate water no matter what, and to keep the engine temperature as uniform as possible throughout the block and head. I think the inline one is asking for cracked head and/or block, but what do I know?

Well, one thing I do know, the stock fan clutch is extremely fragile, wears out very quickly, and engages in the first place way too late. Spring for a Hayden heavy duty, the one that kicks in at 170˚F.

Without question, his stock clutch has failed - They are all complete CRAP and should be junked. The Hayden is a much better option, not just for the lower temperature (and that is AIR temperature coming off the much hotter radiator!) but just because it is a stronger design. Whether you choose to use the 02-07 3.7L gasser plastic fan (With tow package) or stick with the heavier metal CRD fan... That is a personal choice. I contend they both move the same amount of air, but it is MUCH more important that you have a clutch that works.

Now... About the thermostat and Naturist's comment above: I disagree about the inline thermostat being a problem here. When the temperature is at the normal running temp, the thermostat is fully open and offering the better part of a 1 inch port for the water to flow. Our system doesn't flow THAT MUCH water that this would be any more of a restriction than the multitude of small ports in the factory thermostat that REMAIN OPEN all the time once the factory thermostat has failed open. Naturist: You say that the factory thermostat design allows water to flow all the time. This is true, but as Mark (Kapzinski) discovered - The thermostat acts as a double-valve in normal operation, keeping the outflow ports to the radiator and elsewhere closed until the temp was up to spec, then ONLY closing off the "return-to-engine" loop when the engine was up to temp. At all times, the loops through the heater core, overflow / reservoir bottle, EGR, and viscous clutch remain open and flowing.

The loop of "return-to-engine" is a small one, throughout much of its length. This (IMHO) forms far more of a restriction to the easy flow than the momentary reduction to 1 inch from the 1.75 inch main radiator supply line. The FACTORY thermostat port offers less of a clearance when fully open (working OR failed) so I would posit that the failed clutch caused more of his heating issues than the in-hose thermostat, simply because he was loading the engine heavily with that grade and the towing... But the engine had ONLY the forward momentum to cool itself with that 90 degree road-heated air.

Get the Hayden 2905 clutch, put that in and give it another go before you pull that thermostat - Engines have been working with similar sized thermostat holes for decades, and on much larger engines than this one. You just asked a lot of your motor in hot conditions. No surprise that it got a little bit of sweat on.

bigbillyboy · **Joined:** Wed Jun 16, 2010 6:10 pm **Posts:** 75

thanks for all the input. I will absolutely change the fan clutch. Where do I get the hayden fan clutch? Chrysler? Or can NAPA get it for me.

As for the inline T-Stat, I appreciate the comments. I would like to reserve judgement on whether or not it is a bad idea until I get the fan clutch fixed. I will, however, give honest feedback after the fan clutch is installed. If it continues to heat up, I will replace the stock Tstat with no inline heater and see if makes a difference.

I know the Thermostat has been a hot issue on the boards, however, after the stock unit(s) failed twice in 30K miles, it's hard to believe it's a superior design. I still have the stock unit on to direct cooling flow.

I will, for the sake of the knowledge on the board, let you guys know what happens while towing with the in line Tstat.

Thanks.
Jason

bigbillyboy · **Joined:** Wed Jun 16, 2010 6:10 pm **Posts:** 75

Also,
Just to be clear, those of you with working fan clutches and Thermostats, do no experience the engine heating up at all, does it heat up some, just not all the way to 3/4 like mine did? I want to know what is "normal" with an fully functioning cooling system - for the sake of comparison.

ChooChooman74 · **Posted:** Thu Jun 28, 2012 4:29 am

Rockauto.com has the hayden for a reasonable price. Mine is between here and cali on its way to my house.

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mikey1273 · **Posted:** Thu Jun 28, 2012 5:35 am

the hayden 2905 is in the rockauto.com parts catalog for our jeeps, listed price is $45.89

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

Since you have the 2005, it would be important to know if the coolant gauge TSB has been completed by the dealer. They had a reflash available to make the gauge more accurate. With the original setting the gauge normally hits the 3/4 mark before the viscous fan clutch will engage. When the fan cuts in the temp drop is fairly quick. If your fan clutch is failed you would have pegged the gauge.

geordi · **Posted:** Thu Jun 28, 2012 1:05 pm

To add to what Keith (Green Diesel) said there - If your fan clutch was working when the gauge got to 3/4, you would also know about it... It would sound like a locomotive revving up to pull a hill - WWWWHHHHHOOOOOOOOOOMMMMMMMMMMMMMMMMMM!!!!!!!! The change in engine sound is impossible to miss.

You can get the Hayden 2905 clutch locally as well as online at places like Rock Auto - I got mine overnight from O'Reilley Auto Parts for $49. No shipping fees. I haven't yet installed mine, (STILL running no fan other than the electric) b/c it would seem that the blades are a dealer-only item. None of the boneyards have had them either.

The blades are MUCH lighter and move more air if you get the nylon set from the 2002-2007 KJ with the 3.7 gas and the tow package. Dealer cost (IIRC) was like $75.

papaindigo · **Posted:** Thu Jun 28, 2012 1:18 pm

Nylon/plastic 11 blade fan PN 52079654-AE (current #) dealer price $73.35; my I've known the dealer part's manager forever price $60.28. Prices correct as of 6/26/2012 when I picked 2 up (1@ for me and stoutdog). Waiting on Hayden clutches from Amazon $51.19 delivered to my door sometime next week.

naturist · **Posted:** Thu Jun 28, 2012 2:23 pm

I got the factory TSB to make the gauge accurate fairly early on in late 2008, when mine first showed symptoms. At the time, I had just towed my TT over one mountain to/from a nearby campground. I did not realize it then, but my fan clutch had already failed. In fact, I never heard the fan kick in until a year later, in the middle of Montana, when I was towing that TT up a 9% grade on a driveway at 20 mph, just as the gauge pinned itself, to my surprise. I mean, who'da thunk it would do THAT when I wasn't (I thought) running that hard?

I got the clutch replaced (with OEM) on that trip, and next heard the fan kick in when the gauge hit 3/4 going up the west side of the rockies in Arizona. And yes, when the fan DID kick in, it cooled right off. I don't know about the plastic fan, but the metal one is capable of moving a LOT of air. It just has to engage, dammit!

So fast forward to late last summer, a mere 35,000 miles after that, and I'm again towing on my way west, when the fan fails to engage again until the gauge is just one notch off pinned. That is darn late to be getting any help from the fan, and I could only conclude that the stock fan clutch is basically (a) worthless, and (b) meant to be replaced with every oil change.

I got the Hayden clutch, but did not install it until this spring simply because there was no need for cooling over the winter, and why put the miles on the new one when you don't need it? It turned out the damage had already been done, as evidenced by the need for a new head and head gasket just installed a couple weeks ago. So I have yet to give the Hayden its "acid test" by towing that TT over a mountain in the heat, but will be doing so in the next week or so. I may, in fact, drag the TT out for a trial run tomorrow, when the temperature here is supposed to push 100˚F. I'll let y'all know when it kicks in and how the adventure goes.

But one thing is still crystal clear to me: the stock fan clutch is absolutely NOT WORTH THE POWDER IT'D TAKE TO BLOW IT UP, and I will never put another on my CRD.

Budke · **Posted:** Thu Jun 28, 2012 2:24 pm

Remove the mechanical fan all together and put in an electric one. Then add an auxiliary trans cooler.
Trans will stay cooler, engine will stay cooler and there will be less drag on the engine from the mechanical fan so you might see an increase in mpgs.

Sent using the force

Randy B · **Posted:** Thu Jun 28, 2012 3:13 pm

naturist wrote:

The stock fan clutch is a piece of junk. Has been from the get go.

Lots of people experience the same thing: gauge never budges off just left of center, until you tow, uphill, in 80+ weather.

The inline thermostat is not your friend under those conditions. The stock one is designed to circulate water no matter what, and to keep the engine temperature as uniform as possible throughout the block and head. I think the inline one is asking for cracked head and/or block, but what do I know?

Well, one thing I do know, the stock fan clutch is extremely fragile, wears out very quickly, and engages in the first place way too late. Spring for a Hayden heavy duty, the one that kicks in at 170˚F.

I agree

mikey1273 · **Posted:** Thu Jun 28, 2012 4:24 pm

geordi wrote:

To add to what Keith (Green Diesel) said there - If your fan clutch was working when the gauge got to 3/4, you would also know about it... It would sound like a locomotive revving up to pull a hill - WWWWHHHHHOOOOOOOOOOMMMMMMMMMMMMMMMMMM!!!!!!!! The change in engine sound is impossible to miss.

You can get the Hayden 2905 clutch locally as well as online at places like Rock Auto - I got mine overnight from O'Reilley Auto Parts for $49. No shipping fees. I haven't yet installed mine, (STILL running no fan other than the electric) b/c it would seem that the blades are a dealer-only item. None of the boneyards have had them either.

The blades are MUCH lighter and move more air if you get the nylon set from the 2002-2007 KJ with the 3.7 gas and the tow package. Dealer cost (IIRC) was like $75.

If it makes that much noise then I have never had mine fully engaged yet. wonder if mine is broken too? My plan was to replace it when I had a problem with it or when I do the timing belt if not before that. the most I have towed so far is a Popup with gross weight of 1770 and the utility trailer loaded with stone of unknown weight but that was not far like with the camper so I may not be challenging mine enough just yet.

ChooChooman74 · **Posted:** Thu Jun 28, 2012 5:25 pm

Do I really need the plastic one for towing? I don't think that I can get it in before my trip. I was hoping just the clutch would be ok.

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geordi · **Posted:** Thu Jun 28, 2012 5:28 pm

Let me say this for everyone, regardless of mileage or conditions on your CRD (And very likely the gassers too, since they can also use the same clutch)

1: Your stock clutch HAS ALREADY FAILED. I know this as certain as I know the sun will rise tomorrow and that all politicians are full of <something impolite>.

2: If you are not sure if you have ever heard your fan clutch engage... You have not ever heard it, because of #1. Trust me on this one - When it locks on, YOU WILL NOT BE ABLE TO MISS IT. If you are not sure... Read item #1 again.

The average lifespan of the stock clutch varies between 100 miles and however long it takes you to get to the end of your own driveway. I seriously doubt they last any longer than that. No matter what, having a clutch that relies on the air temp coming off the radiator to be at least 195 degrees... That means your engine is AT LEAST 30 degrees hotter - Not good at all. You don't want the cooling to come on like a blast of arctic water at that point, b/c while it might "bring the temp right down" as others have noticed... I would contend THAT does more damage than evenly heating the head / block up or evenly cooling it down. Aluminum and iron expand or contract at different rates, so a rapid cooling could cause problems if there are any persistent hotspots - The rest of the head contracts, stretching that hotspot - cracking it.

With the Hayden coming on at a much lower temperature, the engine is just starting to gain heat when the fan "notices" and the delta (change) between hot and cold will be a lot less, so a lot less violent to the metals involved.

Just buy the Hayden. Even if you keep the metal blades, get rid of that MOPAR clutch. It is junk. If you want to prove it to yourself, that coil at the front is the thermostrip that engages the clutch. You can put the whole unit upright in your oven (at a 200 degree setting) for about 10 minutes to get it good and heat-soaked and then see if the outer clutch vanes are locked to the center shaft (use oven mitts!) as a test (I seriously doubt you will feel any difference) OR - Try just holding a lit match against the thermostrip and see if that locks the shaft. I will go try that outside with my clutch right now, and let everyone know the result.

ChooChooMan - You don't need to replace the blades if you don't want to or don't have time - The clutch is the important part. The blades are a way of "lightening the load" on the engine and maybe saving some MPG from spinning that heavy metal fan.

geordi · **Posted:** Thu Jun 28, 2012 5:34 pm

Test result: The barbeque lighter flame did NOTHING to the thermostrip after 15 seconds of direct contact. You should be able to see the center move. So I pulled out the big gun, a MAPP gas 1500 degree blowtorch. 1 second of contact, and the thermostrip rotated about 1/16 of a turn and stopped with a definite end point. It should have been fully locked. Attempt to turn the shaft... And it moves exactly the same as it did when I picked it up cold.

These stock clutches are COMPLETE JUNK.

engine heats up when towing?

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