BAC Forum

General Boards => Technical Support => Topic started by: George Frudakis on October 09, 2019, 02:31:51 AM

Title: Engine Compartment Fan
Post by: George Frudakis on October 09, 2019, 02:31:51 AM
How to check if my engine compartment fan works? I have never heard it running. Or does it just come on when that area is really overheated?
Title: Re: Engine Compartment Fan
Post by: Steve Huber Co-Admin on October 09, 2019, 02:51:58 AM
George,
If you are talking about the side mounted engine fan, once the engine gets to operating temperature, you can crawl under the coach to see if it is running. Alternately if your C12 runs around 185 most of the time when driving and maybe gets to 200 climbing steep grades, the fan is operating properly. No need to visually check it. The fan on your coach is run by a hydraulic pump and controlled by the wax valve which turns on the fan when the engine temp gets to a point where cooling is needed. Thus at start-up the fan won't be running.
Steve
Title: Re: Engine Compartment Fan
Post by: Fred Cook on October 09, 2019, 01:03:14 PM
Take a marker and mark one of the engine fan blades that can be easily reached and note it’s current  position. Check it after you have ran your coach down the road a ways. If the marked blade is in a different location then the fan has moved and is likely working properly.
Title: Re: Engine Compartment Fan
Post by: Fred Brooks on October 09, 2019, 01:40:23 PM
   If you read all the threads in "Engine cooling fan" , As Mike shared: the radiator fan will turn about 50 rpm when the engine is first started. This is just the fan spinning in by-pass mode and is NOT cooling the radiator. When the engine gets up to 186-188 degrees, the wax valve calls for engine cooling. You can definitely hear it as walk towards it at fast idle. Fred
Title: Re: Engine Compartment Fan
Post by: William Jordan on October 09, 2019, 06:31:39 PM
My C12 Fan is always turning with the engine on. Just not rapidly. Marking a blade clearly wouldn't work.  I assume this is normal.  When it's hot and running at full speed you can definitely hear and feel the difference. If your talking about the aux compartment electric fans on the rear hatch they only come on with high heat in the engine bay and run even with the engine off . I don't know how you'd test but do a walk around check on a hot day with the engine pulling a hill and you'll definitely know they are running. 
Title: Re: Engine Compartment Fan
Post by: Fred Cook on October 09, 2019, 10:10:31 PM
My C12 Fan is always turning with the engine on. Just not rapidly. Marking a blade clearly wouldn't work.  I assume this is normal.  When it's hot and running at full speed you can definitely hear and feel the difference. If your talking about the aux compartment electric fans on the rear hatch they only come on with high heat in the engine bay and run even with the engine off . I don't know how you'd test but do a walk around check on a hot day with the engine pulling a hill and you'll definitely know they are running.

Really?  I wasn’t aware the fan is always turning when the motor is running. I thought it was like a car radiator fan that only turns on at certain temperatures and then idle the rest of the time.
Title: Re: Engine Compartment Fan
Post by: William Jordan on October 10, 2019, 12:29:17 AM
Well in my am start walk around after first starting it is “running” however slowly. You can defiantly tell when it get hot as it’s much faster and the air draw is noticeable. Maybe something is leaking on the valve Letting it move ?? It’s skways been that way the last 5 years I’ve owned it.
Title: Re: Engine Compartment Fan
Post by: Jerry Emert on October 10, 2019, 01:54:22 PM

My fan does not turn at idle when cold.  I just looked a few days ago to find out.
Title: Re: Engine Compartment Fan
Post by: Mike Shumack on October 10, 2019, 08:09:44 PM
Jerry, I was asking a few questions about your hot running transmission, and one suggest was to check to be sure the cooling lines from the transmission to the radiator are not hooked up wrong (crossed). Sounds like something worth looking into. Maybe the factory (or a repair) got the lines hooked up wrong. Does it look like the transmission cooler lines a re long enough to be swapped.

Here's the comment:
Quote
Make sure the trans fluid and the engine coolant "cross flow". If the trans cooler is a bottom tank, make sure the trans flow to the cooler is on the opposite side of the top radiator hose which should be hot coolant from the engine. If the trans cooler is a side tank, make sure the trans oil to the cooler goes in the bottom and out the top.
Title: Re: Engine Compartment Fan
Post by: William Jordan on October 10, 2019, 08:40:15 PM
Curiosity got me and I turned on the diesel with 30 deg outside and walked straight to the fan and it wasn’t running so I was in error. I’m not sure when it starts didn’t want to “test” it in the cold.
Title: Re: Engine Compartment Fan
Post by: Jerry Emert on October 10, 2019, 08:47:09 PM
Thank you.  All good info here!  As I recall, the two hoses from the transmission would not be able to be mixed up.  The one going to the bottom is definitely a lot shorter.  I think I'm going to change transmission fluid this winter, replace the filters and probably take those hoses off to make sure they are not obstructed.  Have to figure out which is which in case they were switched on the transmission side.  Thanks.