Engine/Transmission (1998.5 - 2002) Question on Fan Clutch

[K_Arts]

Lately it has been pretty warm here in CO. . and basically all summer my engine temps have been steady at 195 degrees.



Personally, I feel this is warm and I am surprised that I have NEVER EVER heard my fan clutch engage. Its never engaged since I bought my truck new. Well, I had to take my truck to the local Stealer to recharge my A/C, so at the same time I asked them if they could check out my Fan Clutch. I told them that my truck has been running a little bit warm and I don't feel comfortable with it.



Anyways, to make a long story short, they checked my clutch (Supposedly ) and said that it is working just fine. They said that there was a lot of debris stuck in my radiator and that they cleaned it for me.



Here's my thinking. Usually once a month I go outside with my Air Compressor and a hose and do my best to clean out the radiator. I know it attracks a lot of gunk... . but I still try to keep it clean. First off, how can I keep that sucker clean? Is there any type of aftermarket devide that will help eliminate the gunk from getting to my raidiator?



Also is there anyway that I can make sure my fan clutch is working? I cleaned my radiator the day before I took my truck to the shop so I know they are full of it by saying that they cleaned my radiator.



What's the deal???



Kev

 

[DEZLPWR]

Put a screen in front of your radiator. I have one one mine, and it works great for keeping the flying critters, debris etc. away from the radiator. Any household screen will work. Heck, steal one from your neighbor's house if you want!

 

[TPCDrafting]

My fan clutch engages on hot days when using the A/C runnin' 80 down the highway, but not at full strength. I hear it kick in full strength when pulling the 5 horse loaded on steep hills when I'm down to 3rd gear. Doing this on a hot day and runnin the truck pretty hard it NEVER has gone past 190 degrees. Just my experience. .

It sounds like your's isn't running at all.

 

[Thomas]

Kev,



Want to check the viscous fan drive?



From the model year 2000 Service Manual:

VISCOUS FAN DRIVE



NOISE



NOTE: It is normal for fan noise to be louder (roaring) when:



— the underhood temperature is above the engagement point for the viscous drive coupling. This may occur when ambient (outside air temperature) is very high.



—Engine loads and temperatures are high such as when towing a trailer.



—Cool silicone fluid within the fan drive unit is being redistributed back to its normal disengaged (warm) position. This can occur during the first 15 seconds to one minute after engine start-up on a cold engine.



LEAKS



Viscous fan drive operation is not affected by small stains near the drive bearing. If leakage appears excessive replace the fan drive unit.



If the fan assembly free-wheels without drag (the blades will revolve more than five turns when spun by hand), replace the fan drive. This spin test must be performed when the engine is cool.



For the following test, the cooling system must be in good condition. It also will ensure against excessively high coolant temperature.



WARNING: BE SURE THAT THERE IS ADEQUATE FAN BLADE CLEARANCE BEFORE DRILLING.



(1) Drill a 3. 18-mm (1/8-in) diameter hole in the top center of the fan shroud.



(2) Obtain a dial thermometer with an 8 inch stem (or equivalent). It should have a range of -18°-to105°C (0°-to-220° F). Insert thermometer through the hole in the shroud. Be sure that there is adequate clearance from the fan blades.



(3) Connect a tachometer and an engine ignition timing light. The timing light is to be used as a strobe light. This step cannot be used on the diesel engine.



(4) Block the air flow through the radiator. Secure a sheet of plastic in front of the radiator (or air conditioner condenser). Use tape at the top to secure the plastic and be sure that the air flow is blocked.



(5) Be sure that the air conditioner (if equipped) is turned off.



WARNING: USE EXTREME CAUTION WHEN THE ENGINE IS OPERATING. DO NOT STAND IN A DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.



(6) Start the engine and operate at 2400 rpm. Within ten minutes the air temperature (indicated on the dial thermometer) should be up to 88° C (190° F). Fan drive engagement should start to occur at/between:



—3. 9L/5. 2L/5. 9L gas engines—79°C (175°F)

—8. 0L engine—88° to 96° C (190° to 205° F)

—5. 9L diesel engine—71° to 82° C (160° to 179° F)



Engagement is distinguishable by a definite increase in fan flow noise (roaring). The timing light also will indicate an increase in the speed of the fan (non-diesel only).



(7) When viscous drive engagement is verified, remove the plastic sheet. Fan drive disengagement should start to occur at between 57° to 79° C (135° to 175° F). A definite decrease of fan flow noise (roaring) should be noticed. If not, replace the defective viscous fan drive unit.



CAUTION: Some engines equipped with serpentine drive belts have reverse rotating fans and viscous fan drives. They are marked with the word REVERSE to designate their usage. Installation of the wrong fan or viscous fan drive can result in engine overheating.



CAUTION: If the viscous fan drive is replaced because of mechanical damage, the cooling fan blades should also be inspected. Inspect for fatigue cracks, loose blades, or loose rivets that could have resulted from excessive vibration. Replace fan blade assembly if any of these conditions are found. Also inspect water pump bearing and shaft assembly for any related damage due to a viscous fan drive malfunction.

 

[kaffine krazed]

When you truck is hot open the hood then shut the engine off while watching the radiator fan. How quickly does the fan stop?



As for cleaning the air passages in the radiator. I've had one truck that air was not enough to clean the radiator. I had to use high pressure water to clean the radiator from behind. I kept the nozzle fairly far away from the radiator to be sure I didn't damage the fins. What surprised me the most about it was the fact the radiator was what was blocked not the AC condensor trans cooler or the intercooler.

 

[K_Arts]

Thanks for the replies guys... I really appreciate it. I am highly considering replacing the stock assembly with the perma cool dual 15" electric fans. I'm just trying to figure out how to do it. Meaning, I will have to remove the fan shroud to install the new assembly, but what do I do with the windshield washer fluid and the antifreeze resevoirs?



kaffine krazed - To answer your question about how quickly my fan stops. My fan has always stopped very abruptly and has lived with the notorious belt squeak since day 1 if that matters.



Kev

 

[Rob Thomas]

K arts,



The fan pully will stop when the engine stops, but the fan is on a clutch, and should still be spinning after the engine has stopped, thats what KK was askin about.



Also, do you still have your breather bottle in the stock location? If so, the fan will splatter oil into the radiator, and then any dust will stick like glue to it. I had this happen, since then I removed the damn bottle and re-located the hose to waaaaaay back by the transmission, removed the radiator and powerwashed the crud out of it, and all has been well since.



Later, Rob

 

[K_Arts]

Thanks for the advice Rob. Yepp, still got the stock breather tube in it's original location.



Just how difficult is it to remove the radiator? Is this something that has to be done while changing the coolant?



Thanks



Kev

 

[Rob Thomas]

Kev,



Yes, it's best to replace the coolant while you do this, unless you have a real clean container (6 gallons worth), for the $36 I just replaced it. The radiator is not to hard to remove, drain the coolant, you need to lift off both the washer and over flow bottles, then behind each are 2 bolts you need to remove that hold the shroud on. Then remove the 4 bolts on the top of the rad that sucure the battery cable. Then remove upper and lower hoses, and remove the 2 bolts from from the top of the radiator (1 on each side), and pull straight up, and thats it. Have fun.



Later, Rob

 

[FASTERTHANU]

DO NOT UNDER ANY CONDITION REPLACE YOUR MECHANICAL FAN AND CLUTCH WITH AN ELECTRIC OR DUAL ELECTRIC FANS. IF YOU DON'T BELIEVE ME CALL THE ELECTRIC FAN MANUFACTURERS (DERALE, PERMACOOL,FLEXALITE,SPAL) AND ASK THEM IF THEIR FANS MOVE AS MUCH CFM AS A MECHANICAL FAN W/CLUTCH. YOU WILL HEAR A UNANIMOUS NO. WHILE ELECTRIC FANS WORK WELL TO SUPPLEMENT YOUR COOLING NEEDS YOU WILL FIND THAT THEY ARE WHOLLY INADEQUATE FOR HIGH HP OR LOAD CONDITIONS IN HOT WEATHER OR LOW SPEEDS (THE ONLY TIME YOUR FAN DOES ANYTHING ANYWAY). THE ONLY EXCEPTION WOULD BE AT VERY LOW ENGINE SPEEDS (IE IDLE) AT WHICH ELECTRIC FANS ARE VERY GOOD. IF YOU DO DECIDE TO USE ONE AS A HELPER BE SURE TO LOCATE IT AS FAR OUT OF THE PRIMARY AIRSTREAM AS POSSIBLE AS THEY CAN ACTUALLY IMPEDE YOUR COOLING AT HIGHWAY SPEEDS BY ACTING AS AN OBSTRUCTION IN THE AIRSTREAM. HAPPY HAULIN'

 

[K_Arts]

Originally posted by FASTERTHANU

DO NOT UNDER ANY CONDITION REPLACE YOUR MECHANICAL FAN AND CLUTCH WITH AN ELECTRIC OR DUAL ELECTRIC FANS. IF YOU DON'T BELIEVE ME CALL THE ELECTRIC FAN MANUFACTURERS (DERALE, PERMACOOL,FLEXALITE,SPAL) AND ASK THEM IF THEIR FANS MOVE AS MUCH CFM AS A MECHANICAL FAN W/CLUTCH. YOU WILL HEAR A UNANIMOUS NO.

Ok first let me correct something. I was out looking at some websites... and I apologize, I haven't been looking at the Perma-Cool... actually it was the Flex-A-Lite.



It is model number 290 that they told me will fit my truck and the specs say "Dual 15" blades move 5500 CFM!" (I pulled that straight from their website.



Perm-A-Cool



Here's a PDF file about the series 290



Fasterthanu - Do you or does anybody else have any idea what kind of CFM the stock fan is delivering? 5500 CFM sounds like a ton of air to me, how could this not be sufficient?



Kev

 

[Rob Thomas]

fasterthanu,



I'll havta argue with you on this, or at the least disagree. I have electric fans on my truck and have had them for quite some time, without problems, and I tow daily. Despite what you may have heard, I think they work just fine.



PS ... . Please dont type in all caps, it is considered yelling, and therefore, rude.



Later, Rob

 

[Rob Thomas]

Kev,



5500 cfm will be more than sufficiant, mine dont flow near that much, and they work fine.





Later, Rob

 

[jjdiesel]

load it up

K Arts... do you have a load on your truck? The best test for your fan clutch is to put a good load on your truck and attack one of those mountain grades where you live on a hot day. Your fan may never come on without a load to make that Cummins work. I just came from Leadville last week, pulling my 10k fiver, on the way there I could not hear my fan clutch come on. I replaced it at the campsite with a new one. On the way home, the mountain grades made that baby come on... once I got to flatland, no more clutch fan, more air, less work for the engine... . I guess it didn't need it. Otherwise, I would not have known I had a bad clutch fan. Hope this helps.

 

[K_Arts]

Re: load it up

Originally posted by jjdiesel

K Arts... do you have a load on your truck?

To be honest with you, the biggest load that I have to put on my truck would be our 18ft boat. It probably weights about 3000lbs empty and anywhere from 3500-4000 loaded.



I've towed the boat many times and have never heard the fan come on... including going up some of the mountainous grades.

Yes I've worked my engine pretty hard. There was one time that the wife and I worked the engine to good that the heat within the hood actually started melting the drivers side battery box and actually started a very little fire (Thank god for the fire extinguisher in the boat the fire didn't get out of hand). Even at this time, the engine temps were steady at 195* - 200*



Rob, if you don't mind me asking... what type of electric fan kit do you have installed in your truck?



Kev

 

[Rob Thomas]

k arts,



I have 2 16" mild flowing Perma cools, just for testing purpose's, I will go to higher flowing Flex-a-lite's in the near future. The ones I have were cheap, and in stock locally, so I used them. I haven't had any problems with them, but I only usually tow about 13,500#'s gross, and no moutains in MI.



Later, Rob

 

[FASTERTHANU]

First let me apologize for the caps as I was working on something and just started typing. As far as those of you that have electric fans and have experienced no problems with them that is fine. I've been wrong before, but I would like to submit the following for your consideration.



1) The only cars/trucks the ANY factory uses electric-only fans on are small displacement engines in small cars.

2) I have worked in and currently work in the race/high perf

industry for the past 15 years. Currently I am tech/sales manager for a company that supplies nascar/winston cup and pro stock nhra. Previous to this I was senior sales and tech for Summit Racing. It was during that time at Summit that I attended several training seminars from ALL of the electric fan manufacturers. The engineers from these companies were unanimous in their training that their fans were not capable of cooling over 450-500 hp gas engines on a traditional copper/brass radiator under common "street conditions". These were sales/tech seminars, so if there were no problems with cooling more power than this they surely would not have discouraged us from selling their product as the sole source of cooling on high hp applications (ie blown, large displacement, or high compression).



3) 9 out of ten times when a clutch fan fails it will lock-up solid and overcool, and even if you are the 1 in 10 that looses cooling ability it is usually a gradual loss that can be detected before complete failure. If an electric fan fails then what???... meltdown!



I live in Nevada. the state with more mountain ranges than any other, where outside ambient temperature regularly exceeds 110 degrees with actual road temperatures in excess of 140 degrees. That flexalite fan you are referring to is nothing new.

Call flexalite and ask them how much cfm a clutch fan pulls... they know as they manufacture both . Tell them you are towing 15000 pounds in a bombed turbo diesel over the rockies and ask them if you can run their electric in lieu of the factory stuff. Again I've been wrong before, but my bet is that if dual electric fans worked better than a mechanical fan then the factory engineers would utilize them. On the new model year gen III they have engineered a mechanical fan that has a computer controlled clutch fan, much like the elctro magnetic pieces used on over the road diesels... speaking of over the road big rigs, why don't they use electric fans for primary cooling???? Why the expense of a computer controlled clutch fan??? Remember you have to pull air through the a/c condenser, the intercooler, and the radiator. If you do decide to swap out for electrics I would consider carrying your mechanical with you and a membership to AAA.

 

[K_Arts]

What are saying makes sense don't get me wrong... but I'm still curious as to what kind of CFM our stock fan assembly is delivering?



If it is only pulling say 3300CFM (I just made up this number) and the flex-a-lite is pulling 3300 at 60% power and 5500cfm at 100% power, what would make the mechanical system better? Except for the possibility of any of the electronic stuff failing? That is what I am not understanding.



Kev

 

[FASTERTHANU]

I made a quick call to flexalite tech dept and he (name removed to protect the innocent) said as a round number the turbo diesel clutch fans move about 12,000 cfm (that's 12K) when locked up at 2000 rpm and they (flexalite) do not recommend electrics as primary cooling for these vehicles, but rather as supplemental to the existing system.

 

[Oxjockey]

I think the biggest difference between an engine driven fan on a regular car and the CTD is the RPMs we don't experience. We're pushing less RPMs, which obviously restricts the mechanical fan's ability to move air. The good thing about the electrics is that they blow like mad, even in stop & go traffic.



I have a vehicle with two 12" fans, and if I shut the motor off, leave the fans on, and walk over to the radiator, it's cool to the touch by the time I get there. Kinda neat.



I may be completely wrong, but it's something to consider.



Bryan