Side Radiator wax valve replacement

[Windecker]

Well crud, things did not test the way I wanted them to.

Initial adjustment on 7-21, 1/2 turn IN Drove 185 miles, state routes and some highway, fairly level drive. Temp rose higher than I have ever seen, about 187 at around 70 MPH, 185 at 60 MPH and 182 running in the 50 MPH range. Normally it sort of picks a temp and hangs there so this was a big change.

So I opened the valve again on the 25th, turned it OUT 1 full turn taking back the 1/2 I turned in and adding an additional 1/2 turn as I had recently noticed the temps had been running in the 183 range on the highway which is abnormal for this coach.

I don't think anything changed with the full turn out. Or possibly it got hotter. I saw 190 for a spit second on a fairly level stretch of highway running right at 75. I have Never ever seen that unless climbing a hill. It was wanting to live at 187-188 otherwise on this second test.

I believe my Wax valve did not appreciate being fussed with!

I am suspicious that the "balance" of the temperature spread has gone away. It's working but in a completely different manor than before.

So, I will replace that valve with a new one as I am not in the mood to "try" messing with it. I suspect it is in the process of failing "open" like my last one did, failed open causing the coach to be speed sensitive to temperature (faster speed = hotter coolant temp).

I hooked up my test gauge and shut off valve when I got home to be sure the hydraulics and the fan is capable of running WAO and they are fine.

No changes there so I am confident my valve is unable to properly restrict the hydraulic fluid as is. Maybe I introduced some debris when I adjusted it...

Oh well, it was an old salvage yard valve to begin with, who knows what it has been through.

Think I will change the coolant, filter and hydraulic filter also while I am in there.

One other small thing, it is pretty hot out but normally that does not make the engine run hotter, it just heats up faster on grades which ramps the fan up faster...

Hope they have these in stock!
Windecker

Originally Posted by Ken Thompson

I appreciate your wealth of knowledge. I will wait to hear your results. Thanks!

[Ken Thompson]

I was also hoping for a great result. I had wrenches in hand, ready to crank on that sucker! Maybe I will have to make a call to Source RV tomorrow. Thanks for trying!

[vito.a]

I started with mine at 4 1/2 turns out and it ran 180-190. I then went an additional 1/2 turn out (total of 5) with almost no difference. Next I went 1 more full turn out (total of 6) and it ran 210 plus. I went back in 1/2 turn (total of 5 1/2 turns out) and it runs 195-205. I also topped off the coolant.

The highest I've seen was climbing a mountain pass and it was 206. I'm not sure the adjustment is linear so you just have to play with it.
I do have all new Dexron fluid and a new filter last year. I suspect the hydraulic fluid was original prior to that.

[Windecker]

Thanks Vito for clearing that up. I remember talking with Scott about it at Source and him giving me the start points but I just can't find my notes from that conversation. It is concerning that I turned it the correct direction to lower the temp and it jumped up.

On another note, I ordered the valve from the UK on Sunday when I got home along with some filters and such domestically.

The new valve got here Wednesday, $27.00 freight from the UK, 2 day service (3 days with the time zones it crosses) for a total of $215.00 for the valve and shipping. The filters were $22.00 shipping, ground and have not gotten here yet.

I may see where the currently installed valve is with regards to turns out but I am not messing around taking chances on it failing. I know how that turns out already.
Thanks again Vito!
Windecker
P.S. hows the pump reseal working out?

Originally Posted by vito.a

I started with mine at 4 1/2 turns out and it ran 180-190. I then went an additional 1/2 turn out (total of 5) with almost no difference. Next I went 1 more full turn out (total of 6) and it ran 210 plus. I went back in 1/2 turn (total of 5 1/2 turns out) and it runs 195-205. I also topped off the coolant.

The highest I've seen was climbing a mountain pass and it was 206. I'm not sure the adjustment is linear so you just have to play with it.
I do have all new Dexron fluid and a new filter last year. I suspect the hydraulic fluid was original prior to that.

[jacwjames]

I assume that price is in Pounds Sterling.


I had provided a link to the Whitehouse site in another thread and I think the prices with the Xchange rate was closer to $300.

[Windecker]

No, US dollars. It was 146.27 Euro plus 20.86 Euro shipping, converted to US to $215.11 US.

Originally Posted by jacwjames

I assume that price is in Pounds Sterling.


I had provided a link to the Whitehouse site in another thread and I think the prices with the Xchange rate was closer to $300.

[jacwjames]

Good Price, glad you got one that cheap.

[Windecker]

I folded the top over to protect my account information but this was from White House Products.

Yea, for this price, piece of mind is worth it for sure. Of course one of the new ones I got in 2017 had an out of box failure which led to a nasty couple days but boy did I learn a lot about the system! That's when the salvage valve got installed.
Windecker

Originally Posted by jacwjames

Good Price, glad you got one that cheap.

[jacwjames]

That price is slightly less then I paid in 2015, and the Xchange rate is better so you saved $$.

[Windecker]

Thanks for the diagram and explanation although not being an engineer, it is not helping me personally LOL.

I installed the new valve and changed the coolant, filter and hydraulic filters just because. Afterwards I checked the turns out of the removed suspect valve. It was at 6.2 turns out which maybe explains why the temp had jumped up. I took the valve apart and noticed when I unscrewed the center pilot valve, it turned with zero friction out and only modest friction going in. I suspect my temp valve had changed itself so to speak some.

There is a spring down inside this valve that would not come out. It is possible it is only to provide friction to the pilot shaft, potentially to prevent this self adjusting I may have experienced It is more likely works to push the Wax portion of the valve away from the needle valve. The spring does not directly push on the needle valve. Sort of reverse engineered in a way. It pushes against the body the valve is sitting in and not the valve itself.

Below shows the valve center removed. There is a needle valve, a pilot valve and end cap. Nothing else would come out of the Wax valve body. Unless missing for some reason, there is no spring on the needle valve or between the pilot valve and the end cap.


Shows what I call the pilot valve. It is shaped and similar in size to a 223 shell. It has a hole in the top where the threads are all the way through. It also has holes around the neck of the valve on the sides.


This is looking into the end where the needle valve goes. Not much to see but I was trying to show the valve is hollow and drilled all the way through.

This is the needle valve. The pointed end goes into the pilot valve and will seat against it. The blunt end sits against the Wax valve itself down inside the body of the assembly. I believe when the Wax expands it pushes against the blunt end of the needle valve forcing the tapered end into the pilot seat harder. When pushed into the seat, it prevents hydraulic flow which is coming in the top of the valve, through the pilot valve and is blocked due to this needle valve being forced against it seat inside the pilot valve. When we adjust the depth of this pilot valve, we are moving the needle valve closer or farther from the expanding Wax valve head which in turn changes how much force is applied to the needle valve and seat which changes when the hydraulic flow is metered/shut off. Of course, this is how the fan speed is controlled...


This is looking into the end of the Wax valve body. I was trying to capture the spring down inside. It appears to slid over the tapered end of the pilot valve.


I believe that if this valve were to have a hunk of something between the needle valve and pilot valve seat, you would get a valve that would not allow the fans to run at full speed or come in at the correct temperatures. This would elevate engine temps.

Not sure why a failed valve would cause the fan to come on at full speed all the time. This would indicate to me that the Wax valve head had expanded for some reason or the valve was clogged/stuck.

No long road test this week to see how it pans out with the new valve but I do have a short trip to check basics.

It has been reported that if the inlet and outlet hoses are hooked up backwards that the cooling fan(s) will run at full speed all the time. I am not positive about this but I would wonder if the Wax valve head could potentially be damaged by this. The Wax valve head appears to be copper which is a fairly soft metal and would otherwise not see this kind of pressure when in normal usage.

Lastly, sorry for yet another long read AND I am just a mechanic. If I have something diagnosed wrong or misunderstood how this valve works, it was not intentional to mislead anyone.

Windecker

Originally Posted by kanzkran

that's because the spring is resisting movement of the spool, so adding preload increases the pressure setting of the wax valve unit. It's a relief valve that allows fluid to bypass the fan motor, and as the wax expands, it increases the pressure setting, resulting in higher pressure at the fan motor inlet and more flow through the motor.

The schematic symbol for that valve on the manufacturer's drawing doesn't show a spring, but it seems it's in there nonetheless. Either in series with the wax bulb unit, or in parallel. Like in my quickie sketch below. Note that backing off the spring makes it easier for pressure at the inlet side, through the dashed pilot line, to shift the spool, which in turn bypasses fluid around the motor, and thereby raises the temperature threshold since it takes a higher wax temperature to push the valve closed to reduce bypass flow which in turn spins the motor faster.

[jacwjames]

When I was having trouble with my fan after having my radiator replaced I contacted Monaco Tech Support. Back then you could email and or talk to a rep. After back and forth emails one of the senior techs had me call him and he walked me through the diagnostics.

I though maybe the Cummins shop hooked up the hoses backwards so he had me reverse no change. I put them back and asked if hooking them up backwards would damage the thermovalve and the tech said he did not think so.

Ultimately after replacing the valve like you have done I tore the old one apart "just because" and found pieces of fabric in it, probably where Cummins tech had wrapped it in a rag.

I'm almost positive I was able to remove the inner spring.

[Rightstuffer]

Originally Posted by Windecker

Thanks for the diagram and explanation although not being an engineer, it is not helping me personally LOL.

I installed the new valve and changed the coolant, filter and hydraulic filters just because. Afterwards I checked the turns out of the removed suspect valve. It was at 6.2 turns out which maybe explains why the temp had jumped up. I took the valve apart and noticed when I unscrewed the center pilot valve, it turned with zero friction out and only modest friction going in. I suspect my temp valve had changed itself so to speak some.

There is a spring down inside this valve that would not come out. It is possible it is only to provide friction to the pilot shaft, potentially to prevent this self adjusting I may have experienced It is more likely works to push the Wax portion of the valve away from the needle valve. The spring does not directly push on the needle valve. Sort of reverse engineered in a way. It pushes against the body the valve is sitting in and not the valve itself.

Below shows the valve center removed. There is a needle valve, a pilot valve and end cap. Nothing else would come out of the Wax valve body. Unless missing for some reason, there is no spring on the needle valve or between the pilot valve and the end cap.
Attachment 295649

Shows what I call the pilot valve. It is shaped and similar in size to a 223 shell. It has a hole in the top where the threads are all the way through. It also has holes around the neck of the valve on the sides.
Attachment 295650

This is looking into the end where the needle valve goes. Not much to see but I was trying to show the valve is hollow and drilled all the way through.
Attachment 295651
This is the needle valve. The pointed end goes into the pilot valve and will seat against it. The blunt end sits against the Wax valve itself down inside the body of the assembly. I believe when the Wax expands it pushes against the blunt end of the needle valve forcing the tapered end into the pilot seat harder. When pushed into the seat, it prevents hydraulic flow which is coming in the top of the valve, through the pilot valve and is blocked due to this needle valve being forced against it seat inside the pilot valve. When we adjust the depth of this pilot valve, we are moving the needle valve closer or farther from the expanding Wax valve head which in turn changes how much force is applied to the needle valve and seat which changes when the hydraulic flow is metered/shut off. Of course, this is how the fan speed is controlled...
Attachment 295652

This is looking into the end of the Wax valve body. I was trying to capture the spring down inside. It appears to slid over the tapered end of the pilot valve.
Attachment 295653

I believe that if this valve were to have a hunk of something between the needle valve and pilot valve seat, you would get a valve that would not allow the fans to run at full speed or come in at the correct temperatures. This would elevate engine temps.

Not sure why a failed valve would cause the fan to come on at full speed all the time. This would indicate to me that the Wax valve head had expanded for some reason or the valve was clogged/stuck.

No long road test this week to see how it pans out with the new valve but I do have a short trip to check basics.

It has been reported that if the inlet and outlet hoses are hooked up backwards that the cooling fan(s) will run at full speed all the time. I am not positive about this but I would wonder if the Wax valve head could potentially be damaged by this. The Wax valve head appears to be copper which is a fairly soft metal and would otherwise not see this kind of pressure when in normal usage.

Lastly, sorry for yet another long read AND I am just a mechanic. If I have something diagnosed wrong or misunderstood how this valve works, it was not intentional to mislead anyone.

Windecker

Windecker,

1. Do you happen to remember the wrench size to take off the two small hydraulic lines that screw into the Sauer Danfoss Wax Solenoid?
2. Do you know the wrench size to take the Solenoid off the radiator?
3. And lastly, does anyone know the part number for the #4 Hydraulic line caps to perform the bypass test?

My Wax Solenoid is so dirty after degreasing, I can not even see the size wrenches needed.

I went to a local hydraulic line shop asking for #4 Hydraulic line caps, and they told me there are numbers missing, could be any different parts. They suggested I take off the hoses and bring to them to find one that fits.

[KanzKran]

Originally Posted by Rightstuffer

I went to a local hydraulic line shop asking for #4 Hydraulic line caps, and they told me there are numbers missing, could be any different parts. They suggested I take off the hoses and bring to them to find one that fits.

Assuming you're referring to -4 (dash four) hose fitting size, which is a nominal 1/4" size (4/16), they'd be -4 37 degree JIC male (plugs), based on photos earlier in this thread where the female half was on the hoses. Hex should take a 9/16" wrench.

[Windecker]

Jim,
Yea, that spring surely would come out but I did not work at it that hard. I felt no reason to fight with it.

Paul,
I hate to say it but wow that is dirty back there! Not sure where the leak is that is causing all that dirt to collect, maybe it is just behind the engine breather or something?
I would clean that area very well before opening any hoses up

I am not sure how many combinations there are that Monaco (and others) used but in my case, the valve itself comes off using a 1 7/16 open end wrench. You could likely use slip joint pliers or a very large adjustable if you had to, the valve is not in there "that" tight. It has an O ring at the base to seal it and straight (not pipe) threads. The head of the unit where the hoses attaches swivels and spins so you must grab it by the base of the assembly to turn it.
The two small hoses that hook up are different sizes. The hose furthest from the Wax valve base is the small hose (takes 9/16 wrench) and the hose closer to the base of the Wax valve is the larger hose (which takes a 15 MM metric wrench). It is hard to see in the picture but if you look closely, you can see the different sizes of the fittings and hoses.

This gets strange...

The holes in the base of the valve where the hose fittings hook up are different sizes and OPPOSITE of the large and small hoses.

The fitting that goes into the port furthest from the base is actually a larger diameter hole however using a reducer fitting, reduces it to the 1/4 JSC flair where the hose hooks up. The fitting takes a 5/8 wrench to remove/install it.

The hole closer to the base of the valve is a smaller hole and uses a 9/16 wrench to remove/install it. This fitting appears to be a 1/4 JSC as well however the hose takes a 15MM metric wrench to fit the hose properly.

The two fittings that the hoses hook up to on the Wax valve are straight thread with an O ring under the base to seal it (can be called bulkhead or flange fitting). One is a MS28778-4 and the other is a MS28778-5 I am sure the auto industry has its own part numbers.


The plug you refer to that Tom and Jeri responded to can be found here: https://www.mcmaster.com/jic-fitting.../dash-size~04/

Or here: https://www.wicksaircraft.com/shop/an806-plug/

And frankly, just a 1/4 inch brass pipe plug from Home Depot would work just to do a test. It likely won't be the correct angle but for a few minutes of testing, would be fine. Just use brass because Stainless might damage the hose flair inside.


I have no idea if other coaches use this staggard hose size arrangement or not? In either case, it is all just normal hardware, if you have access to that hardware

Windecker

Originally Posted by jacwjames

When I was having trouble with my fan after having my radiator replaced I contacted Monaco Tech Support. Back then you could email and or talk to a rep. After back and forth emails one of the senior techs had me call him and he walked me through the diagnostics.

I though maybe the Cummins shop hooked up the hoses backwards so he had me reverse no change. I put them back and asked if hooking them up backwards would damage the thermovalve and the tech said he did not think so.

Ultimately after replacing the valve like you have done I tore the old one apart "just because" and found pieces of fabric in it, probably where Cummins tech had wrapped it in a rag.

I'm almost positive I was able to remove the inner spring.