Engine Fan

[SilverFox]

Is there a way to confirm that the engine fan is working without going to the dealer? I have never heard my fan run even though I've seen the water temperature get close to the top of the safe range pulling my travel trailer at altitude. That's way past the center mark.



I hate to turn my truck over to the dealer. I don't have any codes and my engine is totally stock.



Thanks

 

[Prairie Dog]

I only occasionally hear mine when I'm going real slow and have the A/C on and even then, it's only for a very short time. You could crawl underneath and look to see if it plugged in but other than that I'd say relax, It's just so efficient it doesn't have to run hard very often.



Scotty

 

[ChrisKringle]

My temp. never budged running a bulldog 110hp box (timing adv. & pressure), even pulling 5k lbs. (relatively light) 80-90 through a canyon. Now with the TST box, seems to fluctuate between just left of the center mark to just right. Maybe an 1/8 of an inch or so. That's empty. I think our fan clutch is thermo-hydraulic, viscous coupling engages when it heats up. If you start your truck in the morning and take right off, the fluid hasn't had a chance to dissapate so the fan clutch will be engaged. Your engine will 'roar' louder than normal for a few stop lights. Also, when you spin the fan by hand, it should stop within like half a revolution or so. Slight resistance when you spin by hand. When your engine heats up like that, the fan clutch definately should engage, and your engine will make that 'roaring' sound again, most noticable from a stop (kind of hard to hear anything on the freeway). Try Redline Diesel Water Wetter, it's a chemical addative that enhances the thermal conduction propeties of water. Good for 10-20 degrees I believe. Water also conducts heat better than antifreeze, so lower the ratio of anti to water. Finally, turn the ac off.

 

[SilverFox]

Thanks for your answers guys. Like I said, I've never heard the fan running, just wondered if there was a way to check to make sure it was working properly. Somebody posted that you could plug into the computer and that would tell you but I don't want to take it to a dealer until I've exhausted all options. The water wetter mentioned above is something I'm going to look into.

 

[Bill Stockard]

Now that it's warmer in Texas(temps in the 80s), if you turn on the A/C, the fan will cycle off and on as the A/C compressor cycles. When the fan cycles on, you will definitely hear it. I was toying with my "high-tech fast idle device" yesterday and the fan was cycling off and on with the A/C compressor while the engine was fast idling at 1,300 RPM.



Bill

 

[rbattelle]

If you're getting almost to the overheat line, then you definetly have a serious cooling system problem. Could be the fan. I don't hear mine that often, but I do hear it sometimes if I drive away quickly after startup. The ECM does monitor fan RPM, and should set a code if the demand speed doesn't match the actual speed. Such a code should trip the check engine light. If you were all the way over to the right on the temperature gauge, that fan should have been ROARING away. There's a pretty extensive diagnostic procedure for fan problems in the powertrain diagnostics manual. I would definetly take it to the dealer right away.

 

[CIverson]

When I have my plow on it blocks most of the air from the radiator, and after the temp guage gets a hair past the half way point I can hear the fan engage.

 

[jelag]

We pull a 20K to 24K lb trailer with our 04 3500. When climbing the mountains between Roseburg and Sacramento on I-5 were going up the hills at 20-30 MPH... Its the same with the grapevine in LA..... at those speeds we've never had the gauge go higher than mid range... . and you can hear the fan start and stop... ... . If we were at highway speeds..... 55-65 mph I don't think we'd hear it run..... But even across the desert at 100 degrees we haven't had the gauge at more than 210 or so...



I'm guessing that if you see higher than that... . it should be looked at... .



Jim

 

[rholcom2]

Ok, so I just put a new fan clutch on my truck, like 4K miles ago. One of my friends told me there is somewhat of a "break in" period for these clutches. I doubted him, but anyways. My fan "roars" when I am goign slow in all gears almost all the time, in other words when I come to a stop and go to take off again, weather I have driven 2 miles or 200 miles the fan is kicked in when I take off. I bought this fan clutch from NAPA, (sorry guys, I got too good of a deal to buy the DC part). I was told that there is only one listing for the fan clutch for a dodge truck, I noticed when I was installing it that the stock unit is larger in diameter than the replacement, made a phone call, and was assured that the clutch was the right part. I went ahead and installed it. But, my question is this, do I need to have the parts girl get a new one? And do you think I have the right thing, have you ever encountered a smaller diameter clutch when replacing your stock unit?

 

[SilverFox]

Thanks for the help guys. Looks like a trip to the dealer for me, but first, I'm going to try the air conditioning idea advanced by Bill Stockard. I'll have my wife stand by the hood to see if she can hear it come on. (old ears exposed to high noise enviroment over the years) It definitely runs hotter on the gauge than I think it should. If I'm not towing and on level roads it runs slightly below the center mark on the gauge or just touching it which I consider normal.



I've thought about adding a little power to the engine but knew that it would be useless because of engine cooling. I have a feeling this is going to be a learning experience for my dealer.

 

[JWTX]

SilverFox,



I'm in Texas as well. When pulling the 5th wheel my temps are just opposite of what my gasser was. With the A/C off the temps are right at the half way mark. With the A/C on the temps generally run a hair below the half way mark. Only thing that would explain it is the fan, when on, does a great job cooling.



When pulling I can also feel a loss of some power when the fan kicks on, then a return of the power when the fan goes off. BTW, leaving the A/C on when letting the truck idle cools the truck down fast. At least by the dash gauge.

 

[David Oxland]

Here in the North West Coast area I hear my fan when the engine has been warmed up OK and then shut down allowing some of the heat to soak out to he sensor in the fan hub. When I start up then it roars for a min or so until the fan sucks some cool air over the sensor and then goes quiet again.

 

[Bill Stockard]

Originally posted by JWTX

SilverFox,



... leaving the A/C on when letting the truck idle cools the truck down fast. At least by the dash gauge.

Yes, it will do that because the fan is controlled by the ECM. If the truck is setting still without the cooling of ram air going through the radiator, condenser, inter cooler, etc. the high pressure module on the A/C system senses high pressure and sends a signal to the ECM to engage the cooling fan. The fan will run until the high refrigerant pressure drops by either the cooling air flowing across the condenser and/or the compressor cycling off.



The fans on the 3rd gens work similar to the Horton except the OEM fan has a fluid connection instead of the electric clutch and the ECM controls instead of the Horton temperature/pressure senors and relay. One could do the same trick with the Horton... switch on the A/C for a faster engine cool down; however, I had a manual override switch on my previous Horton.



Also see "Engine Runs Hot", TDR Issue 43, page 62.



Bill

 

[Duluth Diesel]

Have any solutions been determined for hot running 600 trucks? What have dealers been doing to remedy this problem? Any input is appreciated. Thanks.

 

[SilverFox]

Thanks guys for all the answers and comments about my fan and engine cooling. To be honest I didn't like the answers I received because I wanted an answer I knew was correct but didn't require me to take my truck to the dealer. Finally, today I took it by and talked to the parts man first and slowly got my nerve up enough to talk to a service manger. I told him my concerns about the temperature being so high and wondering if the fan was working. He said he had a man that understood the scanner and would be happy to check the fan for proper operation.



I said ok let's do it and in a few minutes a young mechanic came out and connected the scanner right in the parking lot. He first checked the circuitry and found that to be ok. Then he ran the engine at high idle for a few minutes with the AC on high. After the engine was as hot as it was going to get he returned the engine to normal idle and within seconds the fan was on and according to the scanner reading 100%, meaning the fan was running as fast as it was programed to run. He said that is what he wanted to see and everything was normal.



Either I'm working my engine harder than most or I always have a load of bugs in my radiator when I'm high in the mountains. I don't like the temperatures I'm getting but at least I'm satisfied the fan is working properly.



Hank

 

[Buzzer]

Originally posted by rholcom2

Ok, so I just put a new fan clutch on my truck, like 4K miles ago. One of my friends told me there is somewhat of a "break in" period for these clutches. I doubted him, but anyways. My fan "roars" when I am goign slow in all gears almost all the time, in other words when I come to a stop and go to take off again, weather I have driven 2 miles or 200 miles the fan is kicked in when I take off. I bought this fan clutch from NAPA, (sorry guys, I got too good of a deal to buy the DC part). I was told that there is only one listing for the fan clutch for a dodge truck, I noticed when I was installing it that the stock unit is larger in diameter than the replacement, made a phone call, and was assured that the clutch was the right part. I went ahead and installed it. But, my question is this, do I need to have the parts girl get a new one? And do you think I have the right thing, have you ever encountered a smaller diameter clutch when replacing your stock unit?

There are 2 fan clutches. One for regular cooling and one for trailer tow. If you have the trailer tow option the bigger clutch is the right one. NAPA might only list one clutch as a replacement but DC lists 2. My sense is you replaced the heavy duty clutch with the regular duty.