DD60 Cooling Fan Runs Constantly

[Mocephus]

Hello friends! I've been struggling for months trying to figure out why the trans temp on our '05 signature DD60 never gets above 125 or so on the gauge or the Aladdin. I realized it was an issue when I couldn't check my transmission oil level at the selector pad because the tranny has to first reach 140 degrees before it will read at the selector pad. I was suspecting a bad temp sending unit on the transmission until a friend on here asked if my cooling fan was running all the time.

 

I was able to check the tranny oil level when we first bought the coach about a year ago, so something has gone south.

 

Last night, while trying to find a small hydraulic oil leak around the hydraulic filter area, I noticed that the cooling fan came on as soon as I started the rig! It stayed on the whole time I had the engine running.

 

I searched our forum but didn't see this issue related to the DD60 discussed before. An interweb search revealed that it could be a plethora of things including an air leak at the clutch, a bad A/C high pressure switch, A/C pressure is too high, the coolant thermostat stuck open, or a faulty air temp sensor...and that's the short list.

 

Have any of you had this same issue? I'm hoping to find the most "common" cause so I can hopefully focus my diagnosis.

 

Also, am I damaging my engine by having it never reach it's "normal" operating temperature?

 

Thank you in advance for your help!

 

[Dr4Film]

If the fan is operating at one speed only commonly called WAO (wide ass open) that would indicate to me that the fan speed controller is shot. Not sure if it controlled electronically or with a wax valve.

Hopefully others with more experience with these valves will chime in.

[Megame]

Hi, we had the same issue last year, it was discovered when I brought the big girl in for a new radiator.  I think it was around $300 plus install, but the install is very doable on your own to install the WACS valve.  No more issues.

[Mocephus]

2 minutes ago, Megame said:

Hi, we had the same issue last year, it was discovered when I brought the big girl in for a new radiator.  I think it was around $300 plus install, but the install is very doable on your own to install the WACS valve.  No more issues.

Hi Randy, we have a trip planned in a few weeks. Will it be harmful to the engine if I can't replace the valve by then?

[Megame]

I don't think it will hurt anything.  Heck we ran with ours like that for about a full year and we full time.  Like any other mechanical beast, it should be changed, but this certainly isn't life threatening, at least in my opinion.  I had no idea ours was in need of changing, we bought the bus and I thought that was just the way it was.  The things you learn as you get into it<grin>  But, easy access on the D60 to change it, and easy to do.  Much easier than a new rad, CAC and oil cooler<grin>

Edited April 18, 2021 by Megame

[KevinH]

I had a similar problem with our rig. My cooling fan ran wide open all the time for the first two years I owned it. I didn’t know this was not normal until someone At a campground told me my RV sounded like a freight train coming through.I researched it and apparently somebody had reversed the hydraulic lines going to the wax valve. I reversed them and it has never done that again.

[Dennis H]

Most common cause is the reversal of the hydraulic lines. Second most common cause is the check valve is bad. Obviously the easiest repair is to reverse the lines and see if it 'cures'...both are easily done by a backyard mechanic.....Dennis

[Frank Bergamo]

Moe,

here is a web site that addresses your problem, http://sourcerv.com/conversion Also if you have the wax valve installed in your coach, here is a site that you can buy a new wax valve way cheaper than any suppliers in the USA. https://www.whitehouseproductsltd.com/products/hydraulic-motors/hyd-gear-motors-fan-valves/dynamatic-fan-drive-motors-valves/553-1-09857-210-thermo Very reasonable price wise, and 5-7 day shipping. The valve is screwed into radiator or is screwed into upper water tube from engine to radiator. Very doable for the average guy with mechanical abilities. If you have the electronic control module, it is best to convert to the wax valve set up. Hope this helps.

 

[waterskier_1]

My 2005 Exec with DD 60 has the fan running at idle.  Monaco had some problems, years ago, where the fans didn't run at idle, and they were damaging the dash A/C components, because there was no air flow across the A/C condenser at idle.  The fix, as I recall, was to put some "restriction" in the hydraulic hose to the wax valve to keep the fan running at idle.  Of course, this applies only to Fan Controller that use the wax valve mounted on the radiator.  I know at some point, Monaco went to an electronic fan controller, and did away with the wax valve controller.   I don't know when, or for which years/engines.  

Regarding doing damage, if it is indeed a fan controller failure (wax valve or electronic) the system is designed to force the fan to run at max speed.  This won't hurt anything except mileage.  I think it takes about 36 HP to run the hydraulic motor at max.  But you'll still have plenty of cooling.  The engine won't care - it has a built-in thermostat (maybe it will think it's in Colorado where it's not above freezing).  It might effect you dash heat, as not as much engine heat will be circulated through the radiator and dash.  You can test the wax valve easily.  Purchase a "coupler" (double female connector to connect the two hydraulic hoses together) and two "caps: (to screw onto the hydraulic hoses to cap them off).  Remove the hydraulic hoses (there will be some oil leakage, so be prepared) and connect both to the "coupler". In this condition you should have minimum fan speed.  Next, remove the "coupler" and cap both hoses.  This should make the fan turn at max speed.  Unless you suspect damage to other components, if this test produces a change in fan speed, your fan motor is working okay.  

I have more details if you need them.

[Mocephus]

1 hour ago, Dennis H said:

Most common cause is the reversal of the hydraulic lines. Second most common cause is the check valve is bad. Obviously the easiest repair is to reverse the lines and see if it 'cures'...both are easily done by a backyard mechanic.....Dennis

Thanks Dennis!

45 minutes ago, waterskier_1 said:

My 2005 Exec with DD 60 has the fan running at idle.  Monaco had some problems, years ago, where the fans didn't run at idle, and they were damaging the dash A/C components, because there was no air flow across the A/C condenser at idle.  The fix, as I recall, was to put some "restriction" in the hydraulic hose to the wax valve to keep the fan running at idle.  Of course, this applies only to Fan Controller that use the wax valve mounted on the radiator.  I know at some point, Monaco went to an electronic fan controller, and did away with the wax valve controller.   I don't know when, or for which years/engines.  

Regarding doing damage, if it is indeed a fan controller failure (wax valve or electronic) the system is designed to force the fan to run at max speed.  This won't hurt anything except mileage.  I think it takes about 36 HP to run the hydraulic motor at max.  But you'll still have plenty of cooling.  The engine won't care - it has a built-in thermostat (maybe it will think it's in Colorado where it's not above freezing).  It might effect you dash heat, as not as much engine heat will be circulated through the radiator and dash.  You can test the wax valve easily.  Purchase a "coupler" (double female connector to connect the two hydraulic hoses together) and two "caps: (to screw onto the hydraulic hoses to cap them off).  Remove the hydraulic hoses (there will be some oil leakage, so be prepared) and connect both to the "coupler". In this condition you should have minimum fan speed.  Next, remove the "coupler" and cap both hoses.  This should make the fan turn at max speed.  Unless you suspect damage to other components, if this test produces a change in fan speed, your fan motor is working okay.  

I have more details if you need them.

Rick thank you for the great tips!

1 hour ago, Frank Bergamo said:

Moe,

here is a web site that addresses your problem, http://sourcerv.com/conversion Also if you have the wax valve installed in your coach, here is a site that you can buy a new wax valve way cheaper than any suppliers in the USA. https://www.whitehouseproductsltd.com/products/hydraulic-motors/hyd-gear-motors-fan-valves/dynamatic-fan-drive-motors-valves/553-1-09857-210-thermo Very reasonable price wise, and 5-7 day shipping. The valve is screwed into radiator or is screwed into upper water tube from engine to radiator. Very doable for the average guy with mechanical abilities. If you have the electronic control module, it is best to convert to the wax valve set up. Hope this helps.

 

Thanks Frank, so I just looked and found that I do have the wax valve that screws into the radiator. It's fairly easy to get to so I should be able to do this job myself. Thanks for the links too!

[Mocephus]

2 hours ago, Dr4Film said:

If the fan is operating at one speed only commonly called WAO (wide ass open) that would indicate to me that the fan speed controller is shot. Not sure if it controlled electronically or with a wax valve.

Hopefully others with more experience with these valves will chime in.

Mine is the wax valve setup that screws into the radiator so hopefully this will be an easy fix!

[vito.a]

A long thread on the Sauer Danfoss wax valve.  There are a couple of DD60 coaches in this thread, but the idea still applies. 

We are getting new wax valves from England at a good price.  

Fan stuck wide open - iRV2 Forums

Also, the Signature should have the A/C condenser up front just behind the front axle with a small fan.  So, it does not require the engine fan for cooling.  

Edited April 18, 2021 by vito.a

[Mocephus]

4 minutes ago, vito.a said:

A long thread on the Sauer Danfoss wax valve.  There are a couple of DD60 coaches in this thread, but the idea still applies. 

We are getting new wax valves from England at a good price.  

Fan stuck wide open - iRV2 Forums

Also, the Signature should have the A/C condenser up front just behind the front axle with a small fan.  So, it does not require the engine fan for cooling.  

Great info! Thank you!

[Frank Bergamo]

Moe,

with fan wide open, the transmission or engine will not reach operating temperature. On my 07’ Marquis, the transmission was running 136-140, engine 155-160. With new wax valve, transmission now runs at 170-180, engine 185-190. Fuel mileage went from 4 MPG to 6 MPG. Not to mention all the stress on the fan spinning wide open. Quite an improvement. Hope this helps.

[Mocephus]

9 hours ago, vito.a said:

A long thread on the Sauer Danfoss wax valve.  There are a couple of DD60 coaches in this thread, but the idea still applies. 

We are getting new wax valves from England at a good price.  

Fan stuck wide open - iRV2 Forums

Also, the Signature should have the A/C condenser up front just behind the front axle with a small fan.  So, it does not require the engine fan for cooling.  

Thank you Vito. My dash A/C is not very cold and without tackling that project I was kind of hoping the two issues were related. Sounds like I’m out of luck there!

[vito.a]

The dash A/C probably needs serviced.  I'd install a new dryer, evacuation, then recharge with 4#  of R134a.  

Ours uses a 4 Seasons dryer # 33276.  Just over $20.  It's located up front on the passenger side of the generator.  

Edited April 19, 2021 by vito.a

[RVSSNAKE]

20 hours ago, Mocephus said:

Mine is the wax valve setup that screws into the radiator so hopefully this will be an easy fix!

I would be curious as to how much fluid loss you have in the change, both hydraulic and radiator. 

(Following) 

[georgecederholm]

20 minutes ago, RVSSNAKE said:

20 hours ago, Mocephus said:

Mine is the wax valve setup that screws into the radiator so hopefully this will be an easy fix!

I would be curious as to how much fluid loss you have in the change, both hydraulic and radiator. 

I’d also be interested in a picture of the wax valve and specifics on part number(s), as I’m pretty sure our 2005 Exec with the DD60 has the Infamous Sauer Danfoss electronic fan controller.

As an aside to one of the comments made in this thread, be wary of dash A/C that’s “not very cold”. It’s probably wise to get a gauge on it and verify pressures, and add refrigerant if needed sooner rather than later. If the R134A gets too low, sometimes these A/C compressors will have the low pressure cut-off switch fail, run on empty, and eventually completely lock up. When that happens, it only takes a few minutes to burn through the serpentine belt. Happened to me in 2012 and again last month. I’d turned the dash A/C on to see if it was cooling on an exercise run and forgot to turn it off. About $250 into the repair so far...

[Mocephus]

32 minutes ago, georgecederholm said:

I’d also be interested in a picture of the wax valve and specifics on part number(s), as I’m pretty sure our 2005 Exec with the DD60 has the Infamous Sauer Danfoss electronic fan controller.

As an aside to one of the comments made in this thread, be wary of dash A/C that’s “not very cold”. It’s probably wise to get a gauge on it and verify pressures, and add refrigerant if needed sooner rather than later. If the R134A gets too low, sometimes these A/C compressors will have the low pressure cut-off switch fail, run on empty, and eventually completely lock up. When that happens, it only takes a few minutes to burn through the serpentine belt. Happened to me in 2012 and again last month. I’d turned the dash A/C on to see if it was cooling on an exercise run and forgot to turn it off. About $250 into the repair so far...

George thank you for the info about the A/C! I'll get that checked right away!

I'll try to remember to track the fluid loss when I make the change. That may be a few weeks depending on how long it takes to get the part. Attached is a photo of my wax valve. I can't read the part number or anything though.

11 hours ago, vito.a said:

The dash A/C probably needs serviced.  I'd install a new dryer, evacuation, then recharge with 4#  of R134a.  

Ours uses a 4 Seasons dryer # 33276.  Just over $20.  It's located up front on the passenger side of the generator.  

Ok thanks Vito! Great info!

[Frank Bergamo]

Moe,
 

the fluid loss will be minimal. Keep the hydraulic lines up and be sure to make a note of there orientation on the wax valve. When unscrewing the wax valve from radiator, be ready to screw new one in as soon as old one is removed. Part number for wax valve is 553/1/09857/210. Whitehouse products is where I got mine. They are in the U.K., so shipping took about a week. There web site is https://www.whitehouseproductsltd.com/products/hydraulic-motors/hyd-gear-motors-fan-valves/dynamatic-fan-drive-motors-valves/553-1-09857-210-thermo Hope this helps.

 

[Mocephus]

38 minutes ago, Frank Bergamo said:

Moe,
 

the fluid loss will be minimal. Keep the hydraulic lines up and be sure to make a note of there orientation on the wax valve. When unscrewing the wax valve from radiator, be ready to screw new one in as soon as old one is removed. Part number for wax valve is 553/1/09857/210. Whitehouse products is where I got mine. They are in the U.K., so shipping took about a week. There web site is https://www.whitehouseproductsltd.com/products/hydraulic-motors/hyd-gear-motors-fan-valves/dynamatic-fan-drive-motors-valves/553-1-09857-210-thermo Hope this helps.

 

Thank you Frank...that makes it easy!

39 minutes ago, Frank Bergamo said:

Moe,
 

the fluid loss will be minimal. Keep the hydraulic lines up and be sure to make a note of there orientation on the wax valve. When unscrewing the wax valve from radiator, be ready to screw new one in as soon as old one is removed. Part number for wax valve is 553/1/09857/210. Whitehouse products is where I got mine. They are in the U.K., so shipping took about a week. There web site is https://www.whitehouseproductsltd.com/products/hydraulic-motors/hyd-gear-motors-fan-valves/dynamatic-fan-drive-motors-valves/553-1-09857-210-thermo Hope this helps.

 

Is there only one kind of wax valve or is it engine/chassis specific?

[Frank Bergamo]

Moe,

 

 The 210 at the end of the part number is the temperature that the fan will run wide open when reached. You can get lower temperature wax valves, but the fan runs faster sooner with the lower temperature wax valve. I believe the lower temp wax valves were used on Monaco chassis that do not have an auxiliary fan on the AC condenser for dash AC. This allowed the fan to run at a lower temp for dash AC, keeping pressure lower, when idling or running at slower or stop and go traffic. Hope this helps

[Mocephus]

4 hours ago, Frank Bergamo said:

Moe,

 

 The 210 at the end of the part number is the temperature that the fan will run wide open when reached. You can get lower temperature wax valves, but the fan runs faster sooner with the lower temperature wax valve. I believe the lower temp wax valves were used on Monaco chassis that do not have an auxiliary fan on the AC condenser for dash AC. This allowed the fan to run at a lower temp for dash AC, keeping pressure lower, when idling or running at slower or stop and go traffic. Hope this helps

Ok thank you!