Forum Discussion

garymunson's avatar
garymunson
Explorer
Aug 19, 2015

Noisy Workhorse engine fan

Has anyone else been irritated by the thermostatic clutch fan on 8.1 liter Workhorse chassis being very loud? I would like to lessen the times I hear it. I have NEVER seen the gauge climb past 1/2 way and the fan will engage when the gauge is at that point and it is hot outside or I am climbing a long hill. It seems that if the thermostat on the fan was set just a little higher, the fan operation would make much more sense. I would think an engagement at a point just beyond 1/2 way would make more sense. I'd changed to a 180 thermostat (from recommended 195). This had the effect of making normal running temp just shy of the 1/2 mark. With the 195 the gauge would go right to 1/2. As it is now, only on very hot days or hill climbing do I see the 1/2 position, then, at that point, the clutch fan will start engaging frequently and cycling. I have NEVER seen the gauge past 1/2 way and would think it would not be an issue if the engine got a little hotter on a long climb or 100 degree day. Obviously the clutch fan is capable of keeping the engine cool in those conditions so if it would only engage at a slightly higher temp, I would be hearing the fan a lot less. Does anyone have an RV that the gauge WILL go slightly past 1/2 before the fan engages in extreme conditions? I'm wondering if my fan clutch is just mis-calibrated. I also have thought about the new waterless coolants and wonder if they will give me the little edge that will lessen fan engagement. Has anyone tried them? An RV uses quite a bit of coolant and the waterless is quite expensive so I'd sure like to hear about other's experiences before I go that route.
Class A
  • DSDP_Don's avatar
    DSDP_Don
    Explorer
    Aug 19, 2015
    Gary....Since you live in Nevada, try the divider to help keep the front cool. Buy an adjustable shower rod and a clear shower curtain. When driving, set it up just behind the front seats. The clear curtain lets you see into the back of the coach and the split allows you to traverse between the front and back.

    I just threw out the dryer hose, but the flexible water heater hose is more stout and comes in some long lengths.
  • garymunson's avatar
    garymunson
    Explorer
    Aug 19, 2015
    I appreciate all the well thought out comments. Hadn't even occurred to me to plug in my scan gauge and do some data logging to see what's actually happening temperature-wise. I also hadn't thought of finding a way to add some extra air flow into the engine compartment with dryer hose. I'll look at doing that right away. I already insulated the doghouse as mine was just a fiberglass shell with the interior carpet serving as the insulation. On truck engines I prefer to run a cooler thermostat as it's unlikely to provide any noticeable mileage improvement. I'm sure the main purpose of it is to get the engine hotter faster to help with smog control. I'm assuming nobody here has used the waterless coolants yet... I should also mention that we have used the RV extensively in the past few months with the heat wave out West here. Despite climbing the Sierra and being in 100+ degree heat, the motorhome never ran the needle past 1/2 way. The dash air was severely taxed during this and we were sitting in two small pockets of cool directly in front of the dash vents. If we had had any more passengers we would have had to resort to the generator and roof air as the rear of the coach was pretty toasty!
  • Clay_L's avatar
    Clay_L
    Explorer
    Aug 19, 2015
    Regarding the temp gauge - it is basically an idiot light. It has four points as shown below. Like others above I use a Scangauge and the fan comes on at about 210 and goes off at about 206.
  • DSDP_Don's avatar
    DSDP_Don
    Explorer
    Aug 19, 2015
    I would leave the fan alone, especially since you have no idea what your gauge is telling you. Saying that you want it to come on after the half way point vs before the half way point is not very scientific. Many wish they had you're issue.

    I would attack it differently......If you don't have the electric fan(S) add one or two. Many RV's with your engine had an issue with keeping the manifolds and plug wires cool because of poor air flow. You can take something like dryer hose and route it from the grill to both sides of the engine. Lastly, increase your doghouse insulation to drown out the sound. Try and get it up around the firewall where you can.
  • Gjac's avatar
    Gjac
    Explorer III
    Aug 19, 2015
    If you search some of the older posts there has been a fair amount of talk about how to adjust some of the fan clutches. There is a bi metal coil spring in front that you can see with a mirror and a flash light. Some have slots to adjust the spring for more or less tension. I wanted mine to act like yours and come on early and mine was potted in silicone so I gave up on the mod. A spring that is covered with dirt and oil acts as an insulator and will cause the fan to come on later, seeing that it works off air temps not the eng temps. I never hear mine unless I am out west on long hills and then it comes on just before the red, but I have an ODB1 connector and I know my gauge is off. As someone else said you can put a switch on the electric fan up front. I turn mine on when I see a hill coming, AC on, a 90 + degree day or whenever I see temps 210 or above.
  • tyoungs's avatar
    tyoungs
    Explorer
    Aug 19, 2015
    Recognize that the fan clutch on/off is based on the air temperature flowing across the fan blades as the engagement is determined by a wax motor - ie, no "direct" connection to engine coolant temperature (unless you have electric clutch then may be ECM controlled by coolant temp). Making sure you have good air flow over and through radiator is best course and making sure shroud directs all the air through and over fan clutch will make sure it is getting proper air flow.
    I would also recommend putting OEM temp stat back in, will slightly improve fuel economy.
  • othertonka's avatar
    othertonka
    Explorer
    Aug 19, 2015
    Put the 195 thermostat back in, manufactures OEM, and learn to live with the roar. I live with it. Use a lower gear when climbing hills to keep the RPM's up for more cooling air and less heat build up. The dash temperature gauge is just an indication of temp and usually stays in the middle. With the OBDII` scan gauge my temp can read 200 to 205 when the dash gauge reads right in the middle. And yes the fan comes on and does it's job, roar and all
  • rgatijnet1's avatar
    rgatijnet1
    Explorer III
    Aug 19, 2015
    On the Workhorse chassis there are already two electric fans in front of the radiator.
    One thing that you need to check is that the fan shroud is intact and properly sealed all of the way around so that all air is directed through the radiator. Naturally you will want to insure that the radiator fins are clean and free of any obstructions.
  • DougE's avatar
    DougE
    Explorer
    Aug 19, 2015
    Having fought with cooling problems and inadequate aftermarket fan clutches my advice is to be happy that it does cycle and does its job!
    Seriously, if it bothers you that much, consider putting a pusher electric fan in front of the radiator and setting it to come on at a lower temperature. It doesn't need to be the full size of the radiator and can reside on the "hot" side.
  • Golden_HVAC's avatar
    Golden_HVAC
    Explorer
    Aug 19, 2015
    With a motorhome making in excess of 150 HP all day long, it will get warm, and require the fan to go to the high speed mode from time to time, when climbing a mountain or running the A/C unit.

    The solutions might be to get a larger radiator, that will run cooler just because it is larger, or to run a smaller electric fan in front of the radiator, and control it so it will come on around 200F and keep the air going over the engine mounted fan under 155F.

    On my engine, when the air going over the fan exceeds 155F, it will cause the fan to run at the same speed as the water pump it is mounted to. Below 145, and it start to idle. With inlet air over 95F, then the radiator does not need to warm the air much more to exceed the 155 out put temp. I find that my fan starts to roar when I get off the freeway and slow the engine down a bit at the stoplight there. Yet it stops roaring after about 30 seconds.

    I just put up with the noise, and leave the radio on.

    Fred.

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