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BrianinMichigan's avatar
BrianinMichigan
Explorer
Jul 21, 2013

Clutch fan operation

I have an issue with the clutch fan kicking in. I was under the impression that once the temps started to get around 195-200 degrees the clutch fan would kick in. With mine, it starts to kick in at just slightly over 180 degrees and once it gets slightly under 180 it will kick out. The radiator was rebuilt about 4-5 years ago and the fan clutch is new. ( The old one worked the same way ) Before the radiator was recored the fan clutch would kick in at around 195 degrees. It seems this all happens when the outside temps get above 80 degrees. I have 180 degree stat in it now and I'm thinking about going down to a 170 degree stat but don't know if it will do any good. The front of the MH is sealed up so any air coming through the grill goes through the radiator and the air dam is in place. Today coming home it was about 70 degrees outside and the engine ran right at 180 and the fan never kicked in.
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  • indyzmike's avatar
    indyzmike
    Explorer
    Jul 21, 2013
    Our last coach was a 1990 Pace Arrow with the 454. It had a 165 thermostat in it and worked fine. I thought a 195 belonged in it, and made the change. The fan kept kicking in so I went back to the 165.
  • BrianinMichigan's avatar
    BrianinMichigan
    Explorer
    Jul 21, 2013
    I have an Auto Meter gauge, beside the know nothing factory gauge that came with it. I have a 180* Stewart thermostat in it now and the gauge is right on 180* and the factory gauge is 1/4 the way up on the display I am pretty certain it's running where it should be. I'm thinking that if the engine ran a little cooler than the clutch wouldn't come on as often. But I guess my thinking is a little simple. As far as the "new" fan clutch goes I have always read here to stay with the factory units because they hold up better.
  • Gjac's avatar
    Gjac
    Explorer III
    Jul 21, 2013
    The fan is actuated by the air temperature not the eng temperature. There are different fan clutch systems but most I believe kick in when the air temps get to 160 F. Mine does the same thing when the outside air is hotter like this week coming back from Maine the outside air was between 95 and 100 F and the dash AC on high the fan clutch came on often when eng temps were about 210-220 F. On 70 F days it would never come on unless I was climbing a steep hill and it would kick in just before the red mark on the gauge. Having said all that as Pappappy said the gauge is probably not that accurate. When I checked mine with the IR gun the temp gauge was 20 degrees higher than the thermostat housing. My thermostat housing was 195 but my gauge said 215 or so. Mine is the old Chevy gauge that shows 100,210 and 260 F. You kind of guess between 210-260.
  • randallb's avatar
    randallb
    Explorer
    Jul 21, 2013
    The fan clutch engagement is not influenced by internal engine temperature. The internal temperature is a direct result of what the radiator and fan clutch are doing in unison. As a radiator gets restricted/older the center of the core is where this restriction normally occurs. With the center of the core restricted the fan clutch does not have heat to read off because a restriction is a cold spot in the radiator. Since the temp radiating off of the center of the core is colder than the portion of the core actually dissipating heat the fan clutch kicks in later, if at all, and the engine runs warmer due to less cooling area and a non-reacting clutch. Now that your radiator is dissipating across its entire surface your fan clutch is reacting correctly.
    Randy
  • rgatijnet1's avatar
    rgatijnet1
    Explorer III
    Jul 21, 2013
    If you replaced the fan clutch with the exact same one, it will probably act the same. You need to find a parts house that can look up a fan clutch that will cut in at 195 degrees. If your coach holds fine at 180 degrees, and you normally do not need the fan to cool things down, then you need to change fan clutches. A good parts house or a GM dealer may be able to help you. Perhaps you need a severe duty clutch from one of the large GM trucks.
  • sch911's avatar
    sch911
    Explorer
    Jul 21, 2013
    Do you have the dash A/C on? This will cause the temps to elevate and the fan to engage also!
  • BrianinMichigan's avatar
    BrianinMichigan
    Explorer
    Jul 21, 2013
    Yah, it's a noise problem. You can't talk on a phone or you really have to raise your voice to talk. I know I could insulate the dog house more but I don't think it will knock down the "roar" that much. The other thing is once it is over 80 degrees it's mostly on and that get tiring.
  • PapPappy's avatar
    PapPappy
    Explorer
    Jul 21, 2013
    It sounds to me, as if it's working? The coolant temp is staying at 180-degrees, so what difference does it make if the fan cuts in or out? Your thermostat is set for 180, so it's probably open....and I doubt that all of these components are extremely accurate with regard to temp., so a degree here or there shouldn't make much difference.

    Is there a specific reason that you are upset that the fan clutch is engaging? Loss of mileage? Noise? I don't see how changing the T-stat would help with that?

    Happy Camping:)

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