| fan clutch revisited [message #257801] |
Mon, 04 August 2014 17:54  |
skip2
Messages: 544
Registered: September 2011
Location: Winter Haven,FL (center o...
Karma: 3
|
Senior Member |
|
|
Good evening,
After listening to my fan clutch this weekend sound like TIA at Thanksgiving I decided it's not right.
I replaced it after I got back from Dothan last year. The one I had bit the big one and didn't do much good sometimes and sometimes it would lock up solid. The one I replaced it with was suppose to be the 15-4208 which I understand is the preferred by some. I don't remember it locking up so much at first but it's got to where it pulls the motor down more than the dash AC, It can even be seen in the vacuum readings between when it releases and when it kicks in. I would dare say it is on 90% of the time. For info sake I run a 180 thermostat to keep the oil a little cooler actually gained a 5 psi when I went to 180 over 195. I digress, My question is, what is the fan clutch that I guess you would call medium duty, I have aux fans which do a pretty good job if needed which I found out when the first one failed. I have tried to research this by looking at old post and internet searches to not bring up something that has been visited many times but the more I look the more confusing it got. Any and all advise and suggestions will be welcomed. On the lighter side someone asked me if the beast was a diesel pusher and I said "It's a gas puller" great way to get strange looks. Thanks
Skip Hartline
74 Canyon Lands, FiTech,
3.7 FD LSD, Manny Tranny,
Springfield Distributor,
2001 Chevy Tracker Ragtop Towd
|
|
|
|
| Re: fan clutch revisited [message #257811 is a reply to message #257801] |
Mon, 04 August 2014 19:37  |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
|
Senior Member |
|
|
The fan clutch should only be needed in rare situations. Stop and go driving with a lot of idling, or pulling a long or heavy grade especially with added weight of a towed vehicle behind are the two main ones.
If yours is kicking on at other times there is definitely a problem. The obvious one every on hops on is a bad clutch. That is always a possibility but if the front seal is not leaking then the clutch is probably not bad. Also try rocking the clutch side to side to see if a bearing is going out.
The second more likely problem is a cooling system problem. I would be looking at the condition of the 35 to 40 year old radiator if it is original. By kicking on, the fan is just trying to make up for an inefficient heater exchanger (the radiator).
I would be cleaning the cooling system and cleaning or replacing the radiator. My personal preference would be to replace it with the Griffin aluminum one sold by Gene Dotson or Jim K. You can always have a radiator shop see if they can clean and or fix the old one. I do not like re-cores when the Griffin one is available
You can replace the clutch again but unless you can see it is definitely bad, I'm afraid that you will just be back fixing the real problem soon.
Do you have a working (calibrated) temperature gage? Do you know if it is really over heating? If it is not overheating then I would suspect a bad clutch engaging when it should not. If it is overheating then the clutch is simply doing it's job and the problem is elsewhere in the engine or radiator.
Oh yes, the 15-4208 is a heavy duty clutch that meets OEM specs. There is one grade heavier available which is severe duty rated. I do not recommend it but many GMC people are using it successfully and they like to hear the noise when it kicks in.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
|
|
|
|
| Re: fan clutch revisited [message #257816 is a reply to message #257801] |
Mon, 04 August 2014 20:13 |
xplorid
Messages: 213
Registered: February 2012
Location: Boise
Karma: 0
|
Senior Member |
|
|
Skip - after suffering with an overactive, over eager hd fan clutch, I installed this:
ACDelco 15-4947 Fan Clutch Assembly
No problems, no complaints, no roar.
Jeff
1974/94 GMCII by Explorer
Manny 6.5 TD Al radiator
1 ton front 4 bags back
|
|
|
|
| Re: fan clutch revisited [message #257849 is a reply to message #257816] |
Mon, 04 August 2014 23:16 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
|
Senior Member |
|
|
xplorid wrote on Mon, 04 August 2014 19:13Skip - after suffering with an overactive, over eager hd fan clutch, I installed this:
ACDelco 15-4947 Fan Clutch Assembly
No problems, no complaints, no roar.
Jeff
There has been years of discussion around fan clutches and my take is that a replacement clutch is less scientific than pure luck. Many of us have experienced heavy duty clutches that are less aggressive than normal duty and the other way around. A few years ago, Ken B found some original Delco cluthes on line and my experience was finally perfect. I do have to say that in AZ heat, a good fan clutch will start engaging at around 90F and be on full time at 100F
Bob de Kruyff
78 Eleganza
Chandler, AZ
|
|
|
|
| Re: fan clutch revisited [message #257858 is a reply to message #257801] |
Tue, 05 August 2014 06:07 |
skip2
Messages: 544
Registered: September 2011
Location: Winter Haven,FL (center o...
Karma: 3
|
Senior Member |
|
|
The radiator is 6 months old and I believe the gauge to be very accurate, when I ran the 195 tstat it ran right at 195 and since I put in the 180 it hangs right on 180.
Skip Hartline
74 Canyon Lands, FiTech,
3.7 FD LSD, Manny Tranny,
Springfield Distributor,
2001 Chevy Tracker Ragtop Towd
|
|
|
|
|
|
|
|
| Re: [GMCnet] fan clutch revisited [message #257873 is a reply to message #257865] |
Tue, 05 August 2014 11:25 |
Dave Motorhome
Messages: 175
Registered: July 2007
Karma: 2
|
Senior Member |
|
|
I went through the fan clutch issue a few summers ago:
Lots of great right ups http://gmcmotorhome.info/engine.html#clutch
the one thing I noticed was the Hayden versions I could get in all had the
hole that accepted the “post” was too small, some have a larger diameter
hole with a bushing to downsize if needed.. I know my terminology is
incorrect but you get the idea.
So I went to the house brand route… I bought o’reilys, AutoZone, Advance,
and NAPA. They were all the EXACT SAME. They literally must have come off
the same factory line and placed in a box. The “stamp” on each clutch was
exact. The only one I did not get in was the AC delco version. For that I
would have bought it from Jim Kanomata, just did not have the time for
shipping.
David Paliotta
75 Glenbrook
Tulsa, OK
http://75glenbrook.googlepages.com/
On Tue, Aug 5, 2014 at 9:44 AM, Chris Choffat wrote:
> GMC Net - Whats the best Fan Clutch?
> Rocketry Online - What's the best glue?
> Solar Forum - Whats the best battery?
>
> Every Forum has one...
>
>
--
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
| Re: fan clutch revisited [message #257881 is a reply to message #257858] |
Tue, 05 August 2014 12:30 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
|
Senior Member |
|
|
I had a response typed up 2 hours ago and the phone rang. It appears I lost it so here it is again.
In summary, you are saying that you do not have a cooling problem. Your current complaint is that the clutch is on most of the time unnecessarily. So IF this is correct then I suggest that you replace the clutch with one equivalent to what you have now.
The AC Delco 15-4208 is a "heavy duty" clutch and equal to the OEM one that GM installed.
The "severe duty" clutch I believe is 15-4644. It spins faster and moves air than the one you have now.
The Hayden clutches kick on at a lower temperature. I got that from the Hayden engineers when I had several both severe and heavy duty Hayden clutches that would not turn off. They actually sent me a couple for free to try. In the end I got my money refunded from Hayden and went to AC Delco.
AC Delco engineers recommended the 15-4208 for the GMC application.
Now comes the problem 15-4208 is now obsolete and has been replaced with another number. You will have to search the forum archives to find the replacement number because I do not have it.
I would recommend that you replace the clutch with a 15-4208 equivalent which is OEM specifications. If you want a noisier one that sucks more power, moves more air, and is harder on the drive belts, then go to Jim K. and get the severe duty AC Delco one that he sells. I believe it is 15-4644. A lot of GMCers use this one. I think they like the noise and quicker cool down when it turns on.
I have a spare 15-4208 that I bought on an ebay closeout a few years back. The clutch says "Made in USA" on it, if that makes any difference to you. Those were being made in Indiana. I'm not positive that is still true.
There are other brands, 4 seasons, NAPA, etc. I have no experience with them so I can not make a recommendation there. From my personal experience and working with their engineering department, I would stay away from Hayden branded clutches.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
