Community Forums

Stansnapp · 05-04-2014, 04:01 PM

This coach is new to us and creates a very noisy wind storm in back, even at idle. I know that huge fan is taking horsepower and adds to fuel consumption. I have a quote from Cummins of $1125. to install a two speed fan that runs slow unless the engine is heating enough to call for the high speed fan operation. Their advice is that I will gain .8 - 1.0 MPG and dramatically reduce noise out the back. If I gain 1.0 MPG at $4.00 per gallon fuel my back of the envelope calculation says it will take 20 K to get my investment back.
Is my calculation roughly correct and would you do the investment? It's kind of like buying a hybrid; it just feels better to be more efficient and to be gaining some return on investment.
Lastly, this is a significant investment for me, a retiree on fixed income or I wouldn't ask.

onechaddude · 05-04-2014, 04:59 PM

I cannot help you with the 2 speed fan but I can offer this. I changed out my fan on my 07 Neptune with Cummins isb 325 hp motor with the source engineering replacement. It made a huge difference in the noise, much much less. I could also feel it had more power. Mine is a little under powered in the first place and I could definitely tell a slight improvement. As far as mpg, I think it slightly improved mine but I do not feel it added 1 mpg. I really think the 2 speed fan will help your power and mpg but I'm not sure it will give you a dramatic increase. Maybe someone with a 2 speed fan already added can give you more precise info.

Chad

dons2346 · 05-04-2014, 09:34 PM

Did you go to the truck repair place north of town on I5 or did you find a Cummins Coach Care?

The problem you have most likely is a bad fan controller which will cost in the neighborhood of $600. Or you could have a bad water temp sensor, or a bad intake temp sensor or a bad high pressure switch on your dash air compressor. Any one of these will be about $50 max. It could also be something as simple as a dirty connector on any of the above components. Get some contact cleaner and clean them.

I had a bad controller and I got 8.5 MPG. Had the high fan running all the time. A new controller got everything back in working order and I still get 8.5MPG, sometimes it is 8.7.

I would not just throw money at it trying to cure the problem, you need to find the cause.

onechaddude · 05-05-2014, 04:57 AM

Quote:

Originally Posted by dons2346

Did you go to the truck repair place north of town on I5 or did you find a Cummins Coach Care?

The problem you have most likely is a bad fan controller which will cost in the neighborhood of $600. Or you could have a bad water temp sensor, or a bad intake temp sensor or a bad high pressure switch on your dash air compressor. Any one of these will be about $50 max. It could also be something as simple as a dirty connector on any of the above components. Get some contact cleaner and clean them.

I had a bad controller and I got 8.5 MPG. Had the high fan running all the time. A new controller got everything back in working order and I still get 8.5MPG, sometimes it is 8.7.

I would not just throw money at it trying to cure the problem, you need to find the cause.

Dons2346 I think the op has a setup that is like my Neptune with Cummins isb 325. The fan is a direct drive off the back of the engine. It does not have a clutch that speeds it up or down on demand like some others. This is the reason many monaco owners add the 2 speed fan or quieter design fan blades.

Chad

dons2346 · 05-05-2014, 11:38 AM

Quote:

Originally Posted by onechaddude

Dons2346 I think the op has a setup that is like my Neptune with Cummins isb 325. The fan is a direct drive off the back of the engine. It does not have a clutch that speeds it up or down on demand like some others. This is the reason many monaco owners add the 2 speed fan or quieter design fan blades.

Chad

Yup, most likely right

Stansnapp · 05-06-2014, 08:58 AM

Looking for someone that has actually had the two speed fan installed. Wanting to know if they thought the $1125. I've been quoted was worth it, would you do it again?

dons2346 · 05-06-2014, 10:34 AM

Quote:

Originally Posted by onechaddude

Dons2346 I think the op has a setup that is like my Neptune with Cummins isb 325. The fan is a direct drive off the back of the engine. It does not have a clutch that speeds it up or down on demand like some others. This is the reason many monaco owners add the 2 speed fan or quieter design fan blades.

Chad

Reading the OP's post, he says he has a ISC 360. I have never seen a ISC with a rear radiator, they have been side radiators which are cooled by a hydraulic fan. Those hydraulic units are controlled by a fan controller, no direct drive involved.

It would be helpful to know what year and model coach the OP has.

Stansnapp · 05-06-2014, 11:02 PM

If I'm the "OP", my original post had my coach. I'm in my second ISC, both with rear radiators. My first was an '01 HR Endeavor 330 ISC that had a 2 speed fan retrofitted when I bought it in '04. My current coach is an '08 HR Ambassador 38' with 360 ISC. I haven't been under it but I'm told it has a serpentine fan belt drive. I pulled the bedroom floor access today but you can only see the Charge Air Cooler fan and only the tops of a couple of blades.
Hope this helps.