Archived Overheating

[KevinK]

I was excited to make my first mountain pass attempt with our trailer and my new setup (DD2s, COMP, DTT transmission) and things started out well (I’m right at 18k lbs. , COMP was on 2x1). I was easily able to maintain 65mph, where I could only maintain 50mph with just an EZ. The transmission was starting to really heat up (240 degrees) and I decided that I should back off when the “Check Gauges” light came on. My water temp was pegged at 240 degrees. I assumed that I was just putting out too much power for the cooling system. I turned the COMP off and over the next pass, I pegged the water temp at 240 again. I could only go a couple of miles and then I had to pull over and let the thing cool off for 10 minutes or so. I wasn’t pushing the truck at all, I was just giving it enough throttle to keep going and making sure that I was not running high RPMS. It still continued to overheat. I now have to get over at least one major pass (Monarch) in order to get home tomorrow.



I can never hear the fan engage, but I could never hear it last year when I went over the same passes and never had a heat issue. Is there any way to force the fan to be engaged 100% of the time? Any other ideas would be greatly appreciated. I’ve got 32k miles on the truck and never had the cooling system flushed, but the system is full. I can pull the trailer all day on flat ground and it runs right at (or just above) 190 degrees.



Thanks,

Kevin

 

[K_Arts]

Sounds like you are kind of having the same issue as me.



Looks like we are both in need of a coolant/thermostat change. . LOL



How many miles are on your current thermostant and coolant?



Kev

 

[Rob Thomas]

Kevin,



Sounds like a bad clutch in your fan, dunno if it can be manually made to run, but they are replaceable. I installed 2 elcetric fans on a temp. switch, it works for me, but haven't tried in a mountain senerio as of yet.



Later, Rob

 

[paccool]

Rob, did you leave the OEM fan on when you put the electric unit on? I was kinda thinking of adding an electric just as an auxillary unit for towing.



Stan

 

[mgerald]

My 98 3500 dually was over heating took it to my mechanic he

told me to replace fan clutch . It fix the problem

 

[LSMITH]

Could also be the thermostat is not opening all the way, but the fan is the #1 suspect. If your fan was working you would know it was, it really roars when it is fully engaged. You can't help but hear it. Monarch is a hard pull too

 

[Rob Thomas]

Stan,



No, I took that stock fan off, it's hangin' on the garage wall.



I don't think there will be enough room fer it with the other fans.



Later, Rob

 

[jsnyder]

Ditto on the fan

You will really hear the fan when it kicks in, which it should as soon as the needle breaks 190*. I've done some hard pulls and never gotten over 195 or so.



Also, if you notice you have a lot of oil vapor blowby and do some dusty dirt road driving, you should check your radiator. I pulled mine this summer to have it recrimped, and the whole front was an oily, dusty, buggy, feathery mess from blowby and other accumulation.



Is your coolant level up? Check the radiator, not the overflow bottle. One of the first things I noticed before I found my radiator leak was that as soon as it was a couple of quarts low it would run at or near 190 much more often.



Good luck!



Jason

 

[KevinK]

Thanks for all of your replies. I couldn't get my internet connection to work again after posting my first message. I was able to get a new thermostat in Gunnison this afternoon and it helped considerably. I replaced the 190* part with a 180* part. Both the engine and the transmission ran cooler. I was able to get over Monarch and Eisenhower passes. However, It still hit 240* about 1/2 mile before reaching the top of each grade. I never could hear the fan engage. I had a '92 Suburban that really did roar when the fan kicked in and the temps dropped quickly. I guess I'll have the dealer take a look.



Thanks again,

Kevin

 

[LaserBob]

Kevin,



Glad that you got some relief. I think that you have it narrowed down to the fan hub. That would be the place I would be looking now. On big rigs, there was a way you could put a bolt in the clutch mechanism and make it solid. Then you were able to drive it when a fan clutch failure happened. These hubs do not have such a spot. Good luck!

 

[K_Arts]

Kevin,



Where did you get the 180* thermostat? I've been looking for one with no luck. My local steal only sells the 190* and it seems that Genos quit stocking them too...



Anyone have any idea where I could find one??



Thanks



Kev

 

[K_Arts]

Also, what type of electric fans are you guys using?



A while ago a ton of people were talking about the Hortons... . is that still the way to go?



Thanks



Kev

 

[Rob Thomas]

Kev,



I got my 180* stat from Cummins P#3954194 under $20.



The fans I'm using are "Perma Cools" I think, dunno about the Horton's, execpt they're pricey. Mine were about $85 each, and seem to be fine, although I haven't towed anything real heavy, up any real grades, 10,000# on flat ground @75* outside was fine tho.



Later, Rob

 

[KevinK]

The DC part number for the 180* thermostat is 05015090AB. Bob Berends had given me the same number during my panic phone call from Lake City (Thanks Bob!), except the last digit was an "A".

I didn't specifically ask for 180*, but that's what I got. I did have to get the part from the dealer (~$30).



With the new thermostat, mine would hold at about 220* (just past the hash mark after 190*) for most of the climb and then in about 5 seconds it would shoot up to 240*. I was running at a constant 2000-2200RPMS in 3rd at about 55mph up the west side of Eisenhower. I was also keeping my foot out of it so that my TC would stay locked up.



I've also gotten conflicting info about whether or not you should be able to hear the fan as it engages. The Dodge dealer said that you can't hear it, but people here have stated that you should definitely hear it.



Kevin

 

[Rob Thomas]

Originally posted by KevinK





I've also gotten conflicting info about whether or not you should be able to hear the fan as it engages. The Dodge dealer said that you can't hear it, but people here have stated that you should definitely hear it.



Kevin

You'll hear it, it sounds like my 6-hp shop-vac under the hood, it's noisy too say the least.



Later, Rob

 

[Bob Wagner]

the dealer is doing you no favors

when the fan clutch engages you <b>really</b> know it.



have faith, you have a great set up

 

[Cummins Corvette]

FYI I can't hear mine when the rpm is lower than about 1800. Between 1800 and 2500 it gets noisy. 3000 rpm... . If you want a positive test to see if it is engaging, put it down a gear and let the rpm go to about 2800. If you STILL don't hear it, you definitely need a new clutch. Good luck.

Chris

 

[Missouri Mule]

kevin,



I never heard my fan go on maybe off. Our fans are always engaged a little.



You should be able to spin fan with your hand there should be a little resistance.



Rob put on (2) electric fans. The battery runs them with remote temp guage.



The Horton has an electric temp sensor and electric clutch.

The fan (Horton) is still run by the engine belt

The electric clutch put out almost 100% engagement where oem fan clutches are about 85%.



I would change coolant and flush coolant system.



When you are running hills especially long or steep climbs you want higher rpm (not red line) but yu want that engine spining at a good clip. Dopping trans into third gear (auto) or fourth gear (5spd).



kevin are you running guages (boost/EGT)?

 

[Extreme1]

To Check the Fan Clutch

Pop the outer end of the bi-metalic spring uot of its mount. You can probably do this by hand but you might need a small screw driver.



The shaft in the center of the clutch that the spring is attached to should now be able to be rotated 45 degrees freely. Mine was siezed in place and overheated on long climbs. You will definately hear and feel the clutch engage.



Besides, who knows more about your truck? A bunch of guys you never met on the internet or your dealer?Oo. :-laf

 

[M Barnett]

Extreme1: Where is this bi-metal spring located?

Michael