Hey guys, thanks for the advice and info. I've actually had the pleasure of replacing the fan clutch a couple months ago along with the water pump, hoses, etc. the problem I'm having is that the fan clutch cycles about every minute. I also just had the radiator recored. The engine runs at about 160 to 170 degrees. The fan clutch comes on about 165 to 170. So after the 700 mile round trip to Yosemite, I am now deaf!
The one I recently put in is from Autozone and I believe it is the x2797 which is made in China. I called my favorite local parts house up north where I like getting my parts, but I didn't talk to the guys I usually deal with. I think he gave me the "screw you" pricing! So I went down to the local Napa store, which I don't really like buying parts from. The really helpful and extremely knowledgable guy was there and helped me. I picked up the Napa 271301 which after some Googling, is almost the same as the Autozone part with the exception that this one is made in the U.S. They are both made by Hayden.
When I replaced the water pump, etc., I put in a 180 degree thermostat. With the engine running between 160 and 170 on the trip last week, I think that is too low. The Napa guy said I should not be running a cooler thermostat and I think he is right. From what he said and from much Google research this afternoon, I think I have one of two problems or a combination of both. It's possible that AutoZone gave me the wrong clutch fan, the one for the pickup. The specs show they are different in diameter and different shaft lengths. My MH is up north so I can't check.
Here is what I think is happening and why we should be running the 195 degree thermostat when the radiator, water pump, etc. are all new and in good working order; the fan clutch engages at a certain air temp flowing through the radiator from the grill. With the 180 degree thermostat, I probably have the thermostat open almost constantly. That means that the air passing through the radiator is probably always at a high enough temp to make the fan clutch engage. With a higher temp thermostat, the hot water from the engine would not be running through the radiator until a later time which means that the air temp passing throu the radiator would be cooler and below the engaging temp of the clutch fan until it is really needed.
I also read that Hayden and another manufacture had at one point lowered the temp that their fan clutches engaged with the bad result of then engaging too much.
Since I won't be able to get the MH out on the highway until my trip to the Oregon sand dunes next month, I think I'm just going to put a 195 degree thermostat back in and also put the Napa fan clutch on.
If nothing else, be sure to read the last paragraph on the last page of this PDF!