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Fan Clutch

Yahoo Message Number: 9984
I've posted on here a few times about experiencing high engine and transmission temperatures. I had the allison dealer here check the flow on the transmisison fluid and everything was good there, they couldn't come up with an explanation for the temps.
So then I took it to the medium duty GM service company here and they say my fan clutch is bad so I need a replacement.

I've heard the stories about these fans blowing apart on here. Is there anything different I should have them do with the fan while they're in there doing the clutch?

Re: Fan Clutch

Reply #1 –
Yahoo Message Number: 9985

My fan blew on my 2006 chassis with 21000 miles this past summer. So it was roughly 6 years old with 5 in service by me. The cost was around $105 for the part. It might be wise money to replace it, but the service shop might have more info on the fans.

Roger

Re: Fan Clutch

Reply #2 –
Yahoo Message Number: 9986
I've had a question in for some time about retrofitting just the fan blade from an ECM controlled 07 and later Kodiak clutch to the clutch on my 06. So far nobody has responded to my inquiry. I don't suppose that anyone has tried as yet. Thoughts?
Denny


Re: Fan Clutch

Reply #3 –
Yahoo Message Number: 9987

Is the fan on the '07 and later void of the failure problem? Has there been any documented failures on the 07's and later?

Roger

Re: Fan Clutch

Reply #4 –
Yahoo Message Number: 9988
If you are having high temperatures while driving down the freeway, then it is not the fan clutch; as the fan doesn't pull in any more air through the radiator than what you get at that speed.

So, if you experience high temperatures while city driving and in stop and go traffic, and NOT on the freeway, then you have a bad fan clutch.

Same will be true with the air conditioning (AC). A bad fan clutch will cause poor AC performance in the city / stop and go traffic, and normal AC performance on the freeway because of the amount of air flow through the AC condenser.

Wink

Re: Fan Clutch

Reply #5 –
Yahoo Message Number: 9990
The mid year 07 fan was redesigned to eliminate the blade end shroud. The pre 07s with the shrouds had in some cases disintegrated and caused considerable damage under the hood. The 07s and subsequent clutches are controlled by the ECMs. I would like to know if the later fan can be bolted to the 06 and earlier clutch? The later fans have not been reported to fail.
Denny



Re: Fan Clutch

Reply #6 –
Yahoo Message Number: 9992
I only see my temperatures heat up when I'm climbing a pretty good grade in the 40 to 50mph range. I'll see my transmission in the 205 to 225 range at freeway speed on fairly level grade.

I've never had a problem with the AC its always worked well no matter the temp or type of driving.

Do you think this guy is just giving me a line about a clutch fan? I've never heard the fan kick on when driving since I've owned the vehicle and I'm told its very noticeable when it does engage.

Re: Fan Clutch

Reply #7 –
Yahoo Message Number: 9993
You could have a dirty cooling stack or partially clogged external trans cooler. It seems that the trans temp is pacing the eng temp. Make sure that there is no debris between the radiator, inter cooler, A/C condenser and external trans cooler. How are you monitoring the trans temp?
Denny

Re: Fan Clutch

Reply #9 –
Yahoo Message Number: 9995
I checked the radiators and sprayed water all through them to try and rinse them, I couldn't see anything in there.

I have an edge CTS thats reading from the transmission. Smith/Detroit Allison did check this and said it was reading temps accurately.

I have a 2006, about 20,000 miles

Re: Fan Clutch

Reply #10 –
Yahoo Message Number: 9997
My fan begins to come in between 198 and 205 degrees. If you haven't heard the fan by 205 degrees in opinion the fan clutch is faulty. I monitor mine on juice attitude.
Denny

Re: Fan Clutch

Reply #11 –
Yahoo Message Number: 9998
There is a bi-metallic spring in the hub on the front of the clutch. With a soft bristle tooth brush gently clean the dust and dirt out of the spring. That spring controls the valving in the clutch. These kodiaks very seldom have over heating problems.
Denny

Re: Fan Clutch

Reply #12 –
Yahoo Message Number: 10002
I picked it up after the fan clutch replacement on my lunch and took it for a drive, headed up the problem canyon, I80E out of Salt Lake City. Reached the top with engine at 205 transmission at 198. Which is 20 to 30 degrees cooler then in the past. Made me feel a little better about spending the money on it. I could now hear the fan as well (hopefully it stays in one piece).
The only trouble came when I had to turn around, it was tough to get the thing turned around and head back to the city and work instead of continuing on to a nice campsite somewhere.

 

Re: Fan Clutch

Reply #13 –
Yahoo Message Number: 10003
Parleys is a good test. We grew up in the Ogden Layton area and have pulled that pass and if I were you I would manually lock out OD and then when you have to put it in third. That way the temps don't get ahead of you. Glad you have improvement. I have been talking about the differences in fans from the 06 and 07s. The 06s have a shrouded blade fan that can come apart if it is sent into over speed. Those early clutches have a mechanism internally that will keep the fan from over speeding. If that safety fails well you see catastrophe can happen. I regularly inspect the shroud for cracks in the filets at the end of the blades to the shroud. Anyway good luck in your travels.