18bogeys Posted August 28 Share Posted August 28 on my 2005 Monaco 400-ISL the small line is the pilot coming from the fan motor bypass valve (bolted to fan motor). The larger line should be your "vent" to tank. As the wax valve or the SD valve closes this moves the shuttle to open flow to your fan motor. I purchased a gauge and gauge tee as well so I could monitor pressure. Here's a picture of the connection and I believe is a #4 Jic which is the pressure side (red plug in the picture) Link to comment Share on other sites More sharing options...
tmw188 Posted August 28 Share Posted August 28 Yep, good additional info. Here’s my motor to compare. Link to comment Share on other sites More sharing options...
18bogeys Posted August 28 Share Posted August 28 That's it! I'm replacing my pump right now because its weak...may be replacing the motor as well when I test the pump. Let me know if I can help on anything else as I've been through the circuit trying to figure out the weak link. The one problem with contamination is that both the case drain from that motor and the Pilot line vent ,bypass the filter back to the tank. I suspect some type of fine contamination failed the pump (not entirely) which may make the motor weak as well. I'm going to flush the system and make sure the fluid is very clear annually or semi-annually now. These parts are hard to get! and expensive! Link to comment Share on other sites More sharing options...
jacwjames Posted August 28 Share Posted August 28 Here is a picture of my old thermovalve, it does have markings for IN/OUT. The caveat is that you have to assume the hoses are connected correctly to start with. You could remove both hoses, put each one in an empty jug and start the engine for a couple seconds and see which one pump hyd out. Link to comment Share on other sites More sharing options...
tmw188 Posted August 28 Share Posted August 28 Ok that’s good to know. I’ll have to look closer at mine again to see if I can see that. Mark one of the lines with tape if ever needing to pull it off. Link to comment Share on other sites More sharing options...
bryan browne Posted October 8 Share Posted October 8 (edited) My 2007 Dynasty run warmer in the high 190 and get hotter on hills, both engine and transmission temperatures. I have never heard the fan speed change or go into anything different than normal startup. does that mean my wax valve is not working.? or something else? Edited October 8 by bryan browne spelling Link to comment Share on other sites More sharing options...
18bogeys Posted October 8 Share Posted October 8 Hi Bryan, On my 2005, both the control valve and pump were/are bad. I still haven't found a wax or control valve but the fan is screaming with the new pump!! There should be a "little" hose and a bigger hose to your wax valve. The small hose is the pressure side (trace it back to your fan motor) and the larger hose continues to your tank. This oil is "vented" to tank by the wax valve. Once the wax valve closes your fan is at full speed. I would buy a needle valve and put it into the little line. When flow is stopped, the shuttle valve in the fan motor moves to full open causing your fan to run fast. You can modulate the needle valve and therefore the fan speed until you get new parts. If its hot where you are you can just leave it closed or just barely open. The system pressure is 3000 psi so make sure you have rated fittings, etc. Finally on operating, my motorhome still needs to run at1800 to 2000 by downshifting. This creates high fan speed as the pump is driven by the motor through your air compressor shaft, it also moves the water pump at a higher speed . I also wouldn't be afraid to cleanup the radiator stack as best you can because I picked up a lot of hay and road grime due to my fan finally working after 3 years of off/on troubleshooting. I haven't had a chance to test my MH in high temps yet, but I know the fan works now. 1.) clean radiator-cheap 2.) plug/valve the small line on your wax valve.-cheap-if you don't hear significant fan speed when blocked then step 3. 3.) Have hydraulic shop verify flow and pressure on pump-lucky to find a pump 4.) Final problem is fan motor.-lucky to find a motor. 1 Link to comment Share on other sites More sharing options...
96 EVO Posted October 8 Share Posted October 8 2 hours ago, bryan browne said: My 2007 Dynasty run warmer in the high 190 and get hotter on hills, both engine and transmission temperatures. I have never heard the fan speed change or go into anything different than normal startup. does that mean my wax valve is not working.? or something else? How much hotter climbing hills? Mine will hover right about 200F climbing grades without the fan going to hi-speed. Like yourself, I've never heard mine go to hi-speed either. 1 Link to comment Share on other sites More sharing options...
bryan browne Posted October 8 Share Posted October 8 (edited) I got to 220 degree engine 218 transmission, engine cools down fast after cresting grade transmission takes longer. last fall I removed my a/c condesor, charge air cooler and cleaned my radiator very well. made a small difference in temps. only owned this bus for 2 years so i have very little past history. Edited October 8 by bryan browne Link to comment Share on other sites More sharing options...
96 EVO Posted October 8 Share Posted October 8 Hmm 🤔. You would think the fan would speed up by 220F! Link to comment Share on other sites More sharing options...
bryan browne Posted October 8 Share Posted October 8 2 minutes ago, 96 EVO said: Hmm 🤔. You would think the fan would speed up by 220F! Im told it should come on after 200 degree +-. so looking for info if wax valve fails to open it its bad? most of what I have read says it fails in high speed. maybe it my pump pressure. Its a shame this many coaches that the parts are so scarce. Link to comment Share on other sites More sharing options...
96 EVO Posted October 8 Share Posted October 8 I wouldn't think your '07 has the wax valve. More likely electronic. 2 Link to comment Share on other sites More sharing options...
bryan browne Posted October 8 Share Posted October 8 1 minute ago, 96 EVO said: I wouldn't think your '07 has the wax valve. More likely electronic. I thought the electronics were earlier 2000's and then they went to wax valves? Link to comment Share on other sites More sharing options...
96 EVO Posted October 8 Share Posted October 8 1 minute ago, bryan browne said: I thought the electronics were earlier 2000's and then they went to wax valves? Pretty sure it was the other way around. Some have switched back to wax valve when their electronic unit failed. That's the way I understand it, but, I've been wrong before, (daily according to my wife ☹️)! 2 Link to comment Share on other sites More sharing options...
bryan browne Posted October 8 Share Posted October 8 4 minutes ago, 96 EVO said: Pretty sure it was the other way around. Some have switched back to wax valve when their electronic unit failed. That's the way I understand it, but, I've been wrong before, (daily according to my wife ☹️)! you are correct, Just went and had a look. Sauer Danfoss electronic #1091140 controller. $1500 to have it rebuilt and $2300 for new. gonna do a little research on the controller first. not sure if its the issue for sure. Link to comment Share on other sites More sharing options...
Frank Bergamo Posted October 8 Share Posted October 8 My 07’ has the wax valve. 1 Link to comment Share on other sites More sharing options...
Bill R Posted October 11 Share Posted October 11 (edited) On 10/8/2024 at 3:08 PM, bryan browne said: you are correct, Just went and had a look. Sauer Danfoss electronic #1091140 controller. $1500 to have it rebuilt and $2300 for new. gonna do a little research on the controller first. not sure if its the issue for sure. If you determine you have a bad SD Controller, for an alternative approach, see attached fix. Several members, including me, have done this fix and are experiencing similar operational results as installing a wax valve or replacing the SD controller. Fix is <$100 and no piping mods to install wax valve. PM me if you are interested in more details. Hydraulic Fan Drive Controller Repair Option.pdf Edited October 11 by Bill R 1 Link to comment Share on other sites More sharing options...
bryan browne Posted October 11 Share Posted October 11 Bill, thanks for the reply, What I am getting from the drawings, we are taking the old electronic controller out of the loop but still using the existing solenoid and hydraulic valve in place as is and just splicing into it? Do I just order any 12v motor controller or do you recommend a part number. Plan on testing my existing solenoid this weekend to eliminated that being the issue. I also have ordered a needle valve to be able to test my fan motor to see if i can get it to speed up. Bryan 314-277-3590 Link to comment Share on other sites More sharing options...
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