Overheating towing in the summer: Fan clutch? Thermostat?

jflem24 · **Posted:** Fri Apr 23, 2010 10:05 am

Hello All,

(not mechanically inclined, so please bare with me)

I read previously that others have experienced this. Towing over a mountain pass in summer the temp gauge reaches about 75% before the fan appears to kick in and cool off the motor. (It was much worse before there was a small computer upgrade shortly after the '05 came out.)

The reason for my question is potential cost and to help point my mechanic in the right direction. I feel that I am done with dealerships, they have their place, but for some repairs, the cost almost seems to outweigh the benefit. If those that have experienced this can tell me what was fixed (Fan clutch, thermostat, etc) and the ballpark of your final bill, that would be great!

Also, I live in the Seattle area. If you anyone has a good recommendation for a mechanic, please let me know. I have taken my CRD to a local place in Kent (Central Auto) and have been pleased thus far. But was curious if there is better out there.

Thank you for your input!
Josh

JL Rockies · **Posted:** Fri Apr 23, 2010 12:29 pm

Fan Clutch.... bill?

BlackLibertyCRD · **Posted:** Fri Apr 23, 2010 12:34 pm

I set the cruise at 1975 RPM in 4th gear lock up and it goes about 62 MPH over the mountain passes around here. You will also get better fuel mileage.

yakers · **Posted:** Sat Apr 24, 2010 12:48 am

I had concerns like yours but have just felt better after info from GDE and others. I tow about a 3,000 trailer across the CA central valley from LA area up to Tahoe. It is often over 100 degrees out. I tow in 4th@60MPH for all the flatter sections. Everything seems cool, run @ 7/16th of the temp gauge, even with AC, towing & 107. Now when I get to the Grapevine its OD off, AC off; sometimes I end up going up in 2nd because of traffic and even turning the heater on to disperse heat. But hey, I'm towing a trailer @104 degrees up a huge mountain; so for 20 minutes out of a long trip I take it as easy as I can. Don't like when the temp gauge heads towards 3/4 but so far there has not been any problem and I understand that the CRD will powerdown rather than overheat. I am more concerned about the transmission (still original@72K miles) but have never seen the trans temp warning light come on (has anyone?).
So, yes, maybe there is an issue with your fan clutch and maybe its time to change the thermostat but maybe everything is fine. If you only have steep uphills occasionally then maybe just slow down and take them easy?

DOC4444 · **Posted:** Sat Apr 24, 2010 11:00 pm

jflem,

Based on your description, everything sounds A-OK, particularly if you have NOT had the instrument cluster TSB (still OK if you have). You mention the fan clutch engaging when the temp gauge is at the 3/4 mark. 05's are notorious for having "weak" fan clutches (replaced mine), but if you hear the "roar" from the fan when the clutch engages, you are good. (I assume this is the cause of your temps going down rather than speed reduction, etc.)

DOC

KeighJeigh · **Posted:** Sun Apr 25, 2010 1:58 am

Hey Josh, I'm up the road from you (Tiger mtn above Maple Valley/Issaquah) and struggled with an overheating problem on my 05 for weeks before figuring out it was the fan clutch, and the only way I could tell for sure was direct side by side comparison to my wife's CRD because when you spun it by hand, it looked "normal". (It would stop spinning immediately) However, if you started both up when hot you could feel the difference in air output when leaning over the motor. I then got out a piece of paper and let it flap around in the breeze created by each and sure enough, it flapped around far more violently the air blowing from the 06 than from the 05.

But the symptoms while driving were odd & not quite what you described:

It happened under very specific conditions that the dealer couldn't repeat while it was under warranty, and since most dealers only go by what's listed in the technical service bulletins, they didn't fix it. Once out of warranty, it became even more serious.
How it worked:
We live about 1300 ft above the valley floor, but the road is winding and slow. Once you get to the bottom of my drive proper, you have another 600 ft to go in 3/4 mi on gravel so it's a slow, steep grind (concrete & lumber trucks loved coming up here when we built). Usually just before I got to the house the gauge would start to climb and within 30 seconds the sucker was 3/4 - or on a hot day, pegged. Sometimes it would happen on logging roads as well. However, it never happened on the highway as you are describing. On the other hand, I only towed snowmobiles a few times in winter up the pass - never a large trailer on a hot day.

So, I'm guessing it's a weak fan clutch. Have them replace that first because the thermostat is not much cheaper & I highly doubt that is the problem. I spent a hell of a lot of time replacing my thermostat, flushing the cooling system & testing & testing only to find out that wasn't the problem. Plus, neither of my CRDs have any trace of corrosion in the cooling system.

- Chris

jflem24 · **Posted:** Mon Apr 26, 2010 4:27 pm

Hello All,

Thank you for the detailed posts, I greatly appreciate it. To answer some of the questions, I do hear the roar of the fan at 3/4 and the engine is quick to cool down. I will keep my ears open and if I get too nervous or scared, I will probably go ahead and have the fan clutch replaced.

Thank you again for the feedback, always learn a lot on this forum.

On a different note, and not sure who will see this or not, but do you use cruise when towing? I have been hesitant to as I am not sure how that would work up slight inclines or long steady climbs over the barrenness that is central Washington. I appears that some do which should help with my towing mileage. I tow from Seattle to Montana or Seattle to Oregon and can get anywhere between 12 and 14, usually depending on the wind direction.

Josh

CRD Joe · **Posted:** Mon Apr 26, 2010 4:51 pm

Lot of Warshentonians on this thread. Im about to tow my moms BMW 325 on a trailer down to Arizona. While I havent experienced any cooling issues with my CRD Im going to pay attention to some of these recommendations on the trip down. We should all get together sometime and talk diesel.....

Tom :goink:

DOC4444 · **Posted:** Mon Apr 26, 2010 6:20 pm

Josh,

Based on your description you have a GOOD fan clutch. I would not replace it unless it stops performing as described. The only thing you might consider is the instrument cluster reflash (if it has not already been done) to make the temp gauge read lower and more accurately.

Also, EGT and trans temp gauges make sense for heavy towing.

DOC

naturist · **Posted:** Mon Apr 26, 2010 9:32 pm

I, too, have a 2005 CRD, and mine had a "weak" fan clutch. Towing a 5,000 lb, full height/width travel trailer uphill/into a strong headwind during warm weather caused the gauge to go up to just under the "H" mark before the fan clutch would engage. I swapped in a new fan clutch and a new thermostat after the dealer's mechanic said the thermostat wasn't opening fully (dunno what test he performed, but it was supposed to be done in 10,000 miles anyway according to the owner's manual) and that resulted in it taking a bit more to cause the gauge to climb, AND the fan clutch engaging at about 3/4, AND the temp dropping back to normal fairly quickly, which it had not done before, so maybe the mechanic was right, the thermostat wasn't opening fully.

Be aware that it should be obvious that the engine is going to make more heat when working hard, and that should cause the temperature to rise to some extent. As long as the temp stays below the "H" (or rather, below whatever real temperature causes blowing off of steam and blowing of head gaskets), that's ok.

It sounds to me as though the OP's CRD is behaving as it should, and he should not worry about what the gauge does.

kapalczynski · **Posted:** Tue Apr 27, 2010 7:36 pm

Under full wide open throttle run up to 120mph I gained only +8* F according to scangauge. Next time I load my 1 ton trailer with rock I will do another run up a long hill and maintain my speed around 60 and see what my temp runs. I doubt it will clime hardly at all. The new cooling capability of the directly connected flex fan setup (adapter w/o the clutch) is phenomenal. I really think it is tha answer to these cooling problems. Tranny temps routinely run cooler also.

http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=51618

- Mark

Overheating towing in the summer: Fan clutch? Thermostat?

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