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So the front AC is cooling only when the original T-Stat is set to On and Cool. I can hear the compressor com on after a short delay 1 minute or less. The compressor will run for approximately 10 minutes then it stops. As the T-Stat is set to on the fan is continuous.  


When the T-Stat is set to auto and cool nothing happens. 

This is new as of Friday 4/14/23. 


Thoughts? What additional information do you need? 


Thanks.

Wondering if anyone has a favorite source for strip brush at the screen door?  Also curious if horsehair is more durable than polypropylene in this application.

We made it back to one of our favorite places… Skidaway Island State Park (site 28). Staying for a week then heading down to Saint Augustine for a week before heading back home to TN. 

Safe travels,
Paul

I knew the radiator had a weeping issued when I bought #484 in 2021. They gave me a discount of the asking price. 

I would only weep occasionally. Usually only after a long day of driving and not a lot of cool down idle time. It slowly started seeping more.
Then after arriving at the Air Museum in Fargo ND last June it spit coolant for several hours. It lost half or so. I should have opened the pressure cap on the tank. That would have likely allowed the crack, or hole to close up again. Hindsight. 

So I drove from Fargo to Spokane to Tonopah with the cap in place but not closed all the way. No leaks no drips and no temps over 208F.  

My goof friend Ken a 20 year helo mechanic and 10 year automotive shop owner looked it over and passed on trying to R&R the RAD/CAC (radiator charge air cooler)

So in talking with Tom during the slide seal party I got the name of Leo the bus mechanic. (MASTER MECHANIC) no matter what he says. 

He had the RAD/CAC sitting on the floor in less than 5 hours. 

The RAD/CAC are at the local radiator shop being evaluated and repaired. No news yet on that end yet. 

I have attached some pictures and a video you might find interesting. 

Thanks Tom and Leo. 




 

Hello all watching this thread. I’m editing this thread to provide current context to my original thoughts and experiences. 
I hope I can save many of you thousands of dollars and hours of frustration by cutting to the chase. 

My coach was built 20 years ago. I have no expectations that twenty year old parts and engineering will be fully functional today however, the past five years have proven to be very frustrating and informative for my wife and I. We have replace almost every component of our suspension and ZF RAS system. We essentially have a new coach from the floor down, the top is still beautiful.

Recently I had a radiator and CAC change. That was accomplished at Newell, thank you Newell for helping me solve problems for my coach and hopefully many others. 

Changing out the CAC and radiator made a significant difference in how my engine performs but that didn’t solve the root case of the problem. I’ll get to that as well.

Recently I had an alignment performed that appears to have corrected all handling problems I’ve struggled with since I purchased #744 in late 2018 and took delivery in 2019. 

I’ll expand on my alignment solution in the thread I started on that topic. I’m a very “Happy Camper” in that category as well. 

Bottom line for my fellow Caterpillar owners, there are a few mechanical items that cause cooling and performance problems with our designs.
 
First and foremost, if you have a single V20 hydraulic pump supplying your ZF gearbox and hydraulic cooling fan motor, your engine will experience high coolant temps and ZF gearbox hydraulic flow and pressure problems. I’m sorry but this is a fact. I will debate this issue if necessary but several Newell Gurus have been along for my ride and understand the problems. 

Tips for success are simple. 
Replace the fan blades before they fail due to heat and age. 

Increase fan blade pitch. More to that than meets the eye. The V20 pump can only handle 2500 psi pressure demand. More to that as well. You fan is set at 20° pitch. You can increase to 27.5° to help airflow but you need to modify other systems to have a winning combination.

Get out ahead of high coolant problems before you overheat your engine. 

Cat 15 owners. Make sure your single V20 hydraulic pump has the proper pump and shaft to last long time. 

Now back to the original thread… 
Good luck! 



I’m exploring what options are available to improve airflow from my cooling fan. 

In my 2005 with a C13 ACERT, Newell installed a MULTI-WING Z Series Fan with “6Z” Blades. I have eight blades. 

I reached out to the U.S. Multi-Wing distributors and was contacted by:
(Larry Brudzynski has retired)

Superior Turbo and Injection. 
313-842-4616 Ext 604.

Larry asked me to send him pictures of my fan. He looked at the blade pitch and estimated the blades are currently set at 25°. He is recommending that I re-pitch the blades to 35°-37.5°. 

Larry is very knowledgeable and helpful. He is a resource for information, parts, or a new fan if necessary.

I’ll provide updates as I continue my research. 

Take care, 
JK

I am posting this info to potentially help anyone contemplating a conversion to mini split. I measured the CFM flows coming from the existing SCS units in our coach with fans on high. 

The combined CFM on the front unit was close to 500 CFM. 
The combined CFM on all the vents from the rear unit was close to 500 CFM. 

I say close because there are lots of factors for getting a super accurate number, and these were crude measurements. But they should give you a number to compare to when looking at flow rates of ducted or cassette units. 

I realize this is somewhat apples and oranges give the generally accepted wisdom that less BTUs are needed with mini splits, and that most mini’s run at much lower CFM because of virtually continuous operation. 

As I think through how to do this on our rig, inquiring minds wanted to know. :-)

I have not had good results with replacing my radiator. I replaced it in 2017 with one obtained from the original supplier. It lasted two years before leaking slightly at the tube header interface. I replaced that one with a core obtained from Rocore. It lasted three years before developing a similar leak at the tube header interface. 

I spoke with the original supplier who was not interested in making a heavier duty core for concerns over cooling efficiency. 

Long sigh. The engineer’s definition of insanity is doing the same thing over and over but expecting a different outcome the next time. The original supplier pointed me in the direction of Thermal Solutions. On their website I found they manufacture a heavy duty core where the tubes are tig welded to the header place instead of the conventional soldering. Like all the core manufacturers they do not sell directly to the public, so I asked them to give me some names of outfits within driving distance who they dealt with. I used Complete Radiator in Orlando, and was absolutely thrilled with their knowledge, service, and pricing. 

I went with Thermal Solutions UltraFuse design https://www.thermalsolutionsmfg.com/wp-c...uty-05.pdf. There are some things of note that I do NOT have real world data on. Obviously, I do not know if this will end up being a more robust solution. Second, the UltraFuse core used less rows of tubes, five instead of six, in the original, but the tubes are 5/8 wide instead of 1/2. And then the fins are V fins in the UltraFuse as opposed to straight fins in the original. I was assured by the radiator folks the UltraFuse design had MORE cooling capacity than the original but that real world data will have wait until the first hot day mountain climb to know for sure. Test drives in flatland Florida on a 90 OAT day did not result in any fan activation, and the engine temp stayed right at the tstat opening temp 196. That is the same result I would have seen with the original design. 

The removal was aided by none other than Bikestuff, and the install by another guru Russ White. Two things are supercritical when removing or installing. One, a work surface such as a lift table to help get the mechanic in and out of the “hole”. And more importantly, a helper to hand items to mechanic in the “hole”. It takes my decrepit bones a good five minutes to wriggle in or out of the confined space. So Mucho Gracias to Bill and Russ. 

I will report back on the longevity as I accumulate miles and hopefully years. I will also report back on cooling performance after a mountain workout.

======================================================================= I want to update this post with real world experience. We have had the opportunity to climb some 6 to 8 % grades in 95 degree temps on the 2024 tour. The core from Thermalsolutions discussed above is cooling just fine. Fan comes on at 204 and drops to 197 in seconds.

i have bought some vevor things and been happy with them.  the last was a 8 gallon heated ultrasonic parts cleaner i am using as i am restoring a 1949 tokheim model 39 gas pump.  
a dometic of this size is over a 1000 bucks.  this one is a quarter of that.  
https://www.vevor.com/car-refrigerator-c...0213874704

tom

A fellow guru is having a bit of an issue on a trip because apparently the mechanisms for allowing the aux compressor to relieve head pressure after cycling have been removed in the new to him coach. Primary symptom is the compressor just hums when trying restart. He has already burned up one compressor on this trip. The owner can release the head pressure on the compressor, and it starts and performs as intended. 

To the purists, the following recommendation is NOT the HWH designed system to relieve pressure from the dessicant bowl. Those part numbers can be found in other posts. 

I post this info here to get the young man back to flushing potties at night as quickly as possible. By posting here it may help someone else in the future. 
First, a compressor unloader is required. https://www.amazon.com/Compressor-Pressu...B0B14TVP77  I have used this one in three applications with no issues. You can pay more for an Ingersoll Rand if you like. 

Second, here is the schematic for piping it in. 

This will replace the SquareD well pump switch for the compressor. 

Pay close attention to the order of the tee and the check valve in the line.

2005 Show coach