Author Topic: Radiator Fan  (Read 20201 times)

Andy Clark

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Radiator Fan
« on: May 22, 2015, 09:33:13 PM »
Our '96 Pat with a Cummins 6CTA8.3 and side radiator has a hydraulically-driven cooling fan.
I've noticed that the fan runs continuously from initial start-up until shut-down. Is this normal, or should there be some kind of thermal switch to turn on the fan only above a certain temperature?
Thanks
Andy
Andy Clark
1995 Patriot 37
300HP Cummings 6CTA8.3
Camano Island WA

Gerald Farris

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Re: Radiator Fan
« Reply #1 on: May 23, 2015, 04:17:55 AM »
Andy,
I have never seen a 1996 Patriot with a Cummins engine, but regardless your side radiator hydraulic cooling fan has a speed control dependent on cooling system needs. The fan runs all of the time but it increases speed when extra cooling is needed therefore requiring more power from the engine to drive it.

Gerald 

Andy Clark

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Re: Radiator Fan
« Reply #2 on: May 23, 2015, 04:51:00 AM »
Thanks, Gerald. That makes sense.
Your answer also explains something else I've wondered about. That is, when I come into a park with gravel or dirt roads after travelling some distance on paved roads or a freeway, the fan kicks up clouds of dust on the passenger side (fan is on the driver's side). It's embarassing because I can't prevent it, and it probably annoys the devil out of the people in the park that I have to drive by (sorry guys). However, when I leave in the am, there's no dust. So you've explained why- in the am the engine is cold and the fan is turning more slowly, but entering the park........WOW!
Thanks again, and BTW, it's definitely a Cummins 8.3.
Andy
Andy Clark
1995 Patriot 37
300HP Cummings 6CTA8.3
Camano Island WA

Gerald Farris

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Re: Radiator Fan
« Reply #3 on: May 23, 2015, 05:45:14 AM »
Andy,
You said that it was a 1996 in your question, but I just noticed that you listed your coach as a 1995 in your signature line. All 1995 Patriots used a Cummings engine on a Spartan chassis.

Gerald

Andy Clark

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Re: Radiator Fan
« Reply #4 on: May 23, 2015, 04:07:36 PM »
Oooops! The "6" is next to the "5" on the keyboard and my fat finger.......

It's a  '95.

Thanks, Gerald.
Andy
Andy Clark
1995 Patriot 37
300HP Cummings 6CTA8.3
Camano Island WA

Rod Ogle

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Re: Radiator Fan
« Reply #5 on: May 26, 2015, 03:19:33 PM »
Gerald

  The radiator fan in our 2004 Patriot C12 does not run at all when the engine is cool, it seems to come on only when the engine starts to get warm.  Are their differences between the production years that accounts for some running all the time or should I start to be concerned?

Rod Ogle
Salem, OR
2004 Patriot Thunder
C12 505

Peter and Connie Bradish

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Re: Radiator Fan
« Reply #6 on: May 26, 2015, 03:40:53 PM »
As some of you may know we have an 8.3 C Cummins mechanical engine. We had problems with the hydraulic fan and overheating the last several years. After lots of parts and time we discovered that our engine had a diverter which controlled the hydraulic fluid. When our engine began to get hot the diverter sent more fluid to the fan and it turned faster, when the engine cooled down less fluid went to the fan and it slowed down.
We discovered that ever since we bought the coach our hydraulic fan was on high all the time. So our engine ran very cool (around 180). Over a number of years the diverter spring began to wear out and the fan wasn't running as fast. So we were beginning to get higher engine temperatures.
Jeff at Bend RV figured it out. Just our luck there was basically no replacement part. Jeff redesigned our system and now the new system works as it's supposed to.
But it sure is disconcerting to see the engine temperature rise and then hear the fan go from lower speed to higher speed. Then when the engine cools down the fan goes back to the lower speed. We are just now getting used to the change. There were lots of anxious moments as we watched the engine temperature climb from 180 up to 200 and then watched the temperature come down. The new normal is beginning to be OK but I still watch the engine temperature gauge a lot when I drive.
Connie B.
« Last Edit: June 05, 2015, 03:59:59 PM by Peter and Connie Bradish »

Gerald Farris

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Re: Radiator Fan
« Reply #7 on: May 27, 2015, 03:17:00 AM »
Rod,
If your fan comes on when it is needed to cool the engine, you have no problem. However, there is somewhat of an exception in that as the engine warms the fan should be running on low speed to cool the CAC (charge air cooler) and the hydraulic cooler. The cooling needs for these two items are independent of the need to cool the engine. If you are sure that the fan does not run on low speed until the engine reaches a temperature that requires high speed fan operation, you might consider having its operation checked.

Gerald 

Rod Ogle

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Re: Radiator Fan
« Reply #8 on: June 04, 2015, 08:29:53 PM »
Gerald

  I did some more checking on when the fan on our 04 PT comes on.  Even with a coolant temperature of 165 the fan did not turn at all.  High speed operation of the fan is supposed to come on around 190 degrees +/-.  I agree with you that the fan should be turning almost all the time to provide cooling to the CAC, transmission and hydraulic system.

  As of now I am suspecting the Sauer Danfoss Thermal valve (wax valve) part # 553/1/09857/190.  Monaco tech support confirmed the part number for our coach and offered one for $734.91 plus shipping, Gillig in Hayward CA has one for $417.24.  Do you have any thoughts to confirm our fan issue is in fact the thermal valve? 


Gerald Farris

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Re: Radiator Fan
« Reply #9 on: June 05, 2015, 12:52:26 AM »
Rod,
Since your power steering is operating normally, your hydraulic pump is functioning properly unless it is wearing and letting metal particles into the system. So that leaves the fan motor or the wax valve, but without trouble shooting the system personally, I can not tell you for sure witch one is malfunctioning. There is also the possibility of a restriction in the system caused by metal particles from the pump. So before I can tell you to replace the wax valve, I would have to check flow rates. However, if you just want to through a part at the problem without thoroughly diagnosing it, the wax valve is a good place to start. 

Gerald

Jerry Carr

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  • 06 Pat. Thunder Cat. C13
Re: Radiator Fan
« Reply #10 on: June 05, 2015, 01:07:23 AM »
Rod the cost of the Danforth valve is much lower from other suppliers, you can purchase this from Danforth directly or from Source Engineering in OR for about half this cost.
Regards,
Jerry Carr
Past Region 1 V.P.
Entegra Anthem
06 Pat. Thunder Cat C13

Rod Ogle

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Re: Radiator Fan
« Reply #11 on: June 05, 2015, 11:57:48 PM »
Gerald

  At the suggestion of Jerry Carr I contacted Source Engineering in Eugene to check on price and availability of a thermal valve (wax valve) for our coach.  I told the tech at Source that I was not sure the wax valve was responsible for the fan not turning.
 
 The tech said there was an easy test.  First disconnect the lines (input and drain) from the wax valve.  Then plug the lines leading to the fan motor, the result would force the fan to run at high speed.  If the fan turns, then we know the hydraulic pump is working and so is the fan motor.

 I followed the suggestion of the tech, and upon engine start up, the fan was spinning pretty fast, no unusual noises or leaks any where.  From this test the culprit is most likely the wax valve, although there is a lesser chance that there is a restriction in the reducer that is positioned between the wax valve and the fan motor.

 BTW, the price of the valve at Source was $595.00 vs $417 at Gillig out of Calif.  I ordered one from Gillig, should be here is 2-3 business days. 

 Rod Ogle
 Salem OR



 

Richard Townsend

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Re: Radiator Fan
« Reply #12 on: August 16, 2021, 08:31:05 PM »
I have a friend in the RV business, out of FL, working quietly/undercover to provide fair to great deals on "ridiculously priced parts".  This WAX Valve is available for $350.00 DELIVERED.  They are a hot item.