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Author Topic: Engine Cooling Fan  (Read 1354 times)

Jerry Emert

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Engine Cooling Fan
« on: October 04, 2019, 05:33:41 PM »
Mike Shumack and I were talking about transmission cooling last night and he asked a question I couldn't really answer.  That was "is your cooling fan working?"  I have never noticed the big cooling fan actually running!  I've never thought about it because I've never had an engine cooling issue.  The hottest I've ever seen may be as high as 205 after a long steep grade on a very hot day.  Usually it runs at 186-192 on normal hot day driving in Eastern Mountains.  Straight and level driving on the interstate on a hot day is normally 186-188.  Those familiar with my obsession with my hot running Allison 4000 will recognize my paranoia. 

So today I started the C-12 for a minute and looked at the fan.  It was not moving at all. 

My question to y'all is, will it?  Will it come on when the engine is cool at an idle even at a slow speed?  Or do I have to get it up to operating temp to see the fan operate? 

As usual any advice or thoughts are welcome.  Thank you.
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH

Rick Daniels

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Re: Engine Cooling Fan
« Reply #1 on: October 04, 2019, 05:47:25 PM »
I had similar observation. I was told that the fan has a engine mounted sensor that turns it on and off but like you, it never came on though I have never attained temp over 206.  The technician installed a on off switch on the console next to the drivers seat below near the Allison pad.  Why he chose to do that instead of trouble shooting or replacing the temp sensor is beyond me but now if I see that the temp is over 200, I hit the button and turn on the fan which I have never had to do.  On the plus side, after driving on a hot or warm day, and I decide to park and go to bed, I turn on the fan and it cools the engine and engine compartment faster therefore the bed is cooler faster.  Before that, going to bed with engine heat still being transferred to the bed was quite uncomfortable.  Kinda like sleeping on a electric blanket in the middle of summer.
1999 Beaver Marquis Jasper 40' Cat C-12
2015 Chev 2500 HD
Three Forks, Montana
"Where the Missouri River Begins"
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Jerry Carr

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Re: Engine Cooling Fan
« Reply #2 on: October 04, 2019, 06:21:24 PM »
The fan will only run when the Danforth wax valve opens. Wax thermostatic elements transform heat energy into mechanical energy using the thermal expansion of waxes when they melt. This wax motor principle also finds applications besides engine cooling systems, including heating system thermostatic radiator valves at a set temp. On the C-13 I could really hear it run after stopping.
Regards,
Jerry Carr
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Jerry Emert

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Re: Engine Cooling Fan
« Reply #3 on: October 04, 2019, 06:25:04 PM »
I had similar observation. I was told that the fan has a engine mounted sensor that turns it on and off but like you, it never came on though I have never attained temp over 206.  The technician installed a on off switch on the console next to the drivers seat below near the Allison pad.  Why he chose to do that instead of trouble shooting or replacing the temp sensor is beyond me but now if I see that the temp is over 200, I hit the button and turn on the fan which I have never had to do.  On the plus side, after driving on a hot or warm day, and I decide to park and go to bed, I turn on the fan and it cools the engine and engine compartment faster therefore the bed is cooler faster.  Before that, going to bed with engine heat still being transferred to the bed was quite uncomfortable.  Kinda like sleeping on a electric blanket in the middle of summer.
Are you referring to the hydraulic cooling fan on the radiator or the one mounted on the engine compartment access door?  I have seen the rear mounted electric fan run a few times when stopped with engine off.  Can you put a switch on the hydraulic fan?  Can the hydraulic fan run without the engine running?  Interesting.
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH

Steve Huber Co-Admin

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Re: Engine Cooling Fan
« Reply #4 on: October 04, 2019, 06:35:05 PM »
Jerry,
WADR adding a switch is effectively fixing something that isn't broken. As Jerry Carr pointed out, the wax valve controls the fan, turning it on when needed. Your stated temps indicate your fan is running fine. IMHO don't mess with it.
Steve
Steve
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2005-2013: 01 Contessa Naples, 3126B, 330 hp
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Rick Daniels

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Re: Engine Cooling Fan
« Reply #5 on: October 04, 2019, 06:50:31 PM »
I was referring to the fan mounted on the engine compartment door (not the engine radiator fan) which I was told is nothing more than a supplemental engine compartment cooling fan.
1999 Beaver Marquis Jasper 40' Cat C-12
2015 Chev 2500 HD
Three Forks, Montana
"Where the Missouri River Begins"
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Mike Shumack

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Re: Engine Cooling Fan
« Reply #6 on: October 04, 2019, 08:01:35 PM »
Next time your driving the coach, when the engine is at normal operating temperature, pull into a rest stop or fuel stop, and head around to the back of coach (while engine is still running of course) see if the fan is turning. At normal engine temperature the fan should be spinning around the same rpm as the engine rpm.

That check alone doesn't prove the fan "switching valve" or wax valve is working fully, but it's a good/easy check to make.
- Mike

'05 Beaver Patriot Thunder 525, Vicksburg, CAT C13, Allison 4000MH, HydraLift
Orlando, FL

Fred Brooks

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Re: Engine Cooling Fan
« Reply #7 on: October 04, 2019, 10:19:53 PM »
  I think we are talking about 2 different fan systems at the same time. The engine radiator fan is hydraulically operated and controlled by the "wax valve" On my C-12 from stone cold, it takes 20 minutes at 1000rpm fast idle to get the fan to engage.The other fan I believe was installed on earlier models with the bed over the engine compartment? This was to exhaust residual hot air out of the engine compartment and not warm up the bed. Not sure if the factory did this or it was an aftermarket add-on to assist in cooling. Advise..... Fred
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Rick Daniels

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Re: Engine Cooling Fan
« Reply #8 on: October 05, 2019, 12:09:12 AM »
Yes, Fred, Mine is a 99 w/cat c12 and the engine compartment cooling fan has every appearance of being factory installed.  and yes, it does cool the bedroom down considerably.
1999 Beaver Marquis Jasper 40' Cat C-12
2015 Chev 2500 HD
Three Forks, Montana
"Where the Missouri River Begins"
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Jerry Emert

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Re: Engine Cooling Fan
« Reply #9 on: October 05, 2019, 01:14:56 AM »
On my C-12 from stone cold, it takes 20 minutes at 1000rpm fast idle to get the fan to engage.
This was exactly what I was wondering!  Would the fan turn at idle on a cold engine.  Fred answered my main question.  So my next step will be to check it during my next driving day.  Thanks Fred!!  I may just install an aux cooler on the transmission this winter.
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH
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Jerry Emert

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Re: Engine Cooling Fan
« Reply #10 on: October 05, 2019, 01:17:18 AM »
Yes, Fred, Mine is a 99 w/cat c12 and the engine compartment cooling fan has every appearance of being factory installed.  and yes, it does cool the bedroom down considerably.
Thanks Rick, I thought we may have got our wires crossed.  I also have the fan mounted on the "hood" and have seen it operate with the engine shut down while unhooking my towed.  Thanks
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH

David T. Richelderfer

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Re: Engine Cooling Fan
« Reply #11 on: October 05, 2019, 02:26:40 PM »
Jerry - Our Marquis had an auxiliary transmission cooler installed by a prior owner.  During our ownership of this Marquis (purchased August 24, 2012 in Eugene) our experience has been the transmission temperature runs about 40F to 45F over the outside temperatures.  In over seven years, the highest temperature I have seen is about 145F.  I have never been able to use the keypad to check the oil level... because it requires a minimum of 140F for that to work.  It has Transynd in it.  The Cat C12 runs between 188F and 194F in almost all situations and has ELC in it.  I think I remember seeing the C12 get up to 204F on a long uphill climb a few times.

I bring this up due to being told several times that running the transmission too cold is not good for it... as is running it too hot.  I believe I was told the minimum transmission temperature should be about 160F but I don't remember where I heard that.
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Mike Shumack

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Re: Engine Cooling Fan
« Reply #12 on: October 05, 2019, 03:17:11 PM »
David, where is your aux cooler located (on the radiator/cac stack, or one of the in-line types like the Rocore)?
What are the aprox dimensions?
- Mike

'05 Beaver Patriot Thunder 525, Vicksburg, CAT C13, Allison 4000MH, HydraLift
Orlando, FL

Carl Boger

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Re: Engine Cooling Fan
« Reply #13 on: October 05, 2019, 05:47:31 PM »
Does anyone have a picture of the engine compartment cooling fans?  Mine doesn't have one, but it sounds like it might be a good addition.
98 Beaver Patriot Savannah

Mike Shumack

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Re: Engine Cooling Fan
« Reply #14 on: October 05, 2019, 06:05:29 PM »
This is on a 99 Marquis.  I believe Jerry's PT has dual fans on the hood.

- Mike

'05 Beaver Patriot Thunder 525, Vicksburg, CAT C13, Allison 4000MH, HydraLift
Orlando, FL