Community Forums

Dan Flores · 02-25-2008, 11:33 AM

I have a 1989 Itasca Sunflyer 25' with a Chevy 454 engine. The noise from the engine is so loud, you can't have a conversation in the driver's compartment. I am going to add some engine insulation to the engine cowl (dog house) in hopes that this will fix it. Are there any other suggestions? I have been told I may need to change the fan clutch with a flex-fan also.

Thanks, D & B

Dan Flores · 02-25-2008, 11:33 AM

I have a 1989 Itasca Sunflyer 25' with a Chevy 454 engine. The noise from the engine is so loud, you can't have a conversation in the driver's compartment. I am going to add some engine insulation to the engine cowl (dog house) in hopes that this will fix it. Are there any other suggestions? I have been told I may need to change the fan clutch with a flex-fan also.

Thanks, D & B

RustyJC · 02-25-2008, 11:54 AM

First, welcome to iRV2.com.

It's good to have you with us.

A flex fan is the opposite of what you need for motorhome or heavy towing service. A flex fan flattens out and moves less air as engine RPMs increase. In fact, the flattened blades will block ram air flow through the radiator. Now, picture your RV climbing a steep grade on a hot day. The vehicle speed is low (little ram air through the radiator) and engine RPM is likely high (so the flex fan will be flattened out and not moving air). Under these circumstances, I would worry if I didn't hear the fan clutch kick in and start moving lots of cooling air.

Rusty

Gary RVRoamer · 02-25-2008, 01:19 PM

I suspect they meant a thermostatically controlled fan rather than a flexible blade fan. That would imply a hub change.

You can get automotive underhood insulation and line the inside of the "doghouse" with it. It may help some. Will definitely reduce the engine heat in the cab area.

NeilV · 02-25-2008, 06:38 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by D & B:
I have a 1989 Itasca Sunflyer 25' with a Chevy 454 engine. The noise from the engine is so loud, you can't have a conversation in the driver's compartment. I am going to add some engine insulation to the engine cowl (dog house) in hopes that this will fix it. Are there any other suggestions? I have been told I may need to change the fan clutch with a flex-fan also.

Thanks, D & B </div></BLOCKQUOTE>

Apply the KIS priciple and K(eep) I(t) S(imple) by insulating the dog house with a good quality sound insulation designed for engine compartments before conisdering anything else. On my coach the effect was quite dramatic using just the kit sold at Camping World. It was about an hour into our first trip after insulating the dog house that we realized that we were not shouting any more.

One time I forgot to turn the engine off and when I asked a friend who was inside the coach assisting me to turn it off for me he just looked at me kind of funny and after turning it of told me he could not hear it running at idle speed and thought I was kidding him at first. He has ordered a kit also now.

Try it and you may be plesantly surprised.

As for the flex fan, I agree with Rusty that it is not the best match for a motorhome.

Jackm · 02-25-2008, 08:50 PM

The easiest and best way to reduce engine noise is to insulate the doghouse cover. The gold standard of sound and heat insulation is a product from Dynamat (Product #11905). The cheapest place to get it is from the Hifi Sound Connection Web site (hifisoundconnection.com). The product from Camping World is adequate but the product from Dynamat is exceptional. You will be pleasantly surprised at the improvement. Best of luck.

Jack

Dan Flores · 02-26-2008, 07:17 AM

Rusty, Gary, Neil & Jack,

Thank you all for the valuable input. I have ordered the engine insulator that Jack suggested. You guys probably saved me a lot of time and money with the flex-fan idea as well. Makes sense that it wouldn't be the best way to go, especially when towing. All of this is new to me, but a great learning experience.

Dan

JoeH · 02-27-2008, 05:43 PM

Make sure you check your fan clutch too . if it is defective and locked in, not only is it loud but negatively impacts fuel mileage.

Dan Flores · 02-28-2008, 06:00 AM

Thanks Joe. What's the best way to check it? You cannot see it from under the cowl or when opening the hood.

Dan

Clay L · 02-28-2008, 07:33 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by D & B:
Thanks Joe. What's the best way to check it? You cannot see it from under the cowl or when opening the hood.

Dan </div></BLOCKQUOTE>

You should be able to see it from underneath the motor home.
My last coach was a 1995 P30 chassis with a 454 and the service manual had a procedure for checking the fan clutch. They said to measure the temp of the AIR coming out of the radiator. I used a metal meat thermometer. I had to drill a small hole in the plastic shroud around the fan so I could get the thermometer between the fan and the radiator.
They said to block the radiator with cardboard and run the engine at about 2000 RPM to get the engine to heat up.
The fan will spin before it's fully engaged, but it's obvious when it engages because of the noise.
It should engage at an air temp between 165"F and 195'F. If it doesn't it should be replaced.

If it's fully engaged all the time it should also be replaced.