Loud engine noise

[JimmyP]

We recently bought an 03 Dolphin with an 8.1 Chevy engine. We often hear a loud roaring noise coming from the engine compartment. It sounds as if the engine is reving up but it is not that. It will do this for a minute or so then slowly fade away. I believe it is related to the fan clutch or engine cooling fan but the engine temp is normal. This is very annoying. What do you think it is and can it be stopped or remedied somewhat. Thanks for your help.

[JimmyP]

We recently bought an 03 Dolphin with an 8.1 Chevy engine. We often hear a loud roaring noise coming from the engine compartment. It sounds as if the engine is reving up but it is not that. It will do this for a minute or so then slowly fade away. I believe it is related to the fan clutch or engine cooling fan but the engine temp is normal. This is very annoying. What do you think it is and can it be stopped or remedied somewhat. Thanks for your help.

["007"]

Jim, you are correct they are your fans, the temp gage will not move much up or down from 3 o'clock which is normal for 8.1.
Make sure you have the correct level of fluid in your over flow tank for radiator and no blockage in front of your radiator.
Living in Florida and using AC will cause the fans to come on more than normal.
One other thing to check is your air dam to make sure most of the air is being forced thru your radiator if its torn around it your fans will come on more often.

Congrats on your new MH.

[Horsepowerfan]

Yessir, when that fan clutch engages it does make quite a roaring noise! Aside from the suggestions given by 007, if everything checks out OK, there's not much you can do about it and it is normal. My co-pilot here is asking, "are you talking about the loud noise that sounds like it's gonna blow up" usually just before cresting a hill?

There is mention of this noise in the Workhorse Owner's Manual which you may have received with your coach and also in the Workhorse Gas Motor Home Chassis Guide (which you can download for free from Workhorse.com. Click Here to link to the Workhorse Forum where you'll find information about this manual which is a great resource for the care and feeding of your Workhorse. )

[KTYSTR]

Yes there are the two air conditioner fans that cycle on, make a fair amount of noise, and then fade away.
However, there is also, in addition to that noise, a very loud roar that sounds like things truly are going to come apart that has occurred on my coach in hot conditions and stop and go traffic. I am told that is the engine fan which is in behind everything you typically see. I was told that I was probably loosing a bearing or water pump. Nothing dire has happened in the last 7-8K miles since I last heard it, so I suspect it is simply the engine fan running in addition to the air conditioner fans. No workhorse center can find a cause, nor get it to happen for them, so it is not something I can have fully analyzed or repaired.
Perhaps you have experienced this same noise. It is NOTICEABLY different than the typical fan cycling noise.

[cannon man]

its the big white clutch fan between your engine and radiator. yes its too loud and yes it is normal. only fix would be more sound insulation. dave

[Rocky Larson]

I am working on this issue today, again. Due to your discription I located the white fan by looking over the front tires (both sides)at the rear of the radiator. A shroud seam is double fastened on each side of the fan.(maybe more seams I can't see). With the engine running and howling away I touched the shroud in several places. Each touch eliminated the sound completely. For everyone that went the same route I did, fruitlessly I might add, looking for the solution forwards in the engine compartment, or with "It's normal" explainations, this might be the fix. I'll try tightening or adding fasteners and report on the results.

[oemtech]

Be sure the lower half of the shroud is screwed to the radiator frame. Failure to do so could cost you a radiator. Here is what happens when it is not screwed drown.


Note - I added the screw while I waited for parts.

[Rocky Larson]

Thanks for the great picture. Saves me the trouble of crawling back under with my camera. The hole in my shroud was about three times the one in your picture. I trimmed up the rough edges and cable tied it so it stopped rubbing. No more noise. The screw will be in place tomorrow. Thanks again