Very little heat from dash heat registers while underway

[Rustymayes]

With my rig under warranty, a pulley was replaced because the belt was shredding. You might have the same issue?
Probably shouldn't rely on the jacks to be the sole item holding up the rig. Should also have jack stands in case a hose fails. Throughout the years of reading forums, I've read people posting friends have been crushed.

I would not trust the jack system to hold the rig in the air with the wheels removed to do any chassis work with out secondary jacks for sure! I ran the rear jacks all the way up with the front jacks lowered but still on the ground to gain room to drain the anti freeze. When I went to level the coach again I heard some unusual and concerning banging noises I assume caused by binding. I think it best to limit taking the jacks to the extreme like that. I was on a level concrete shop floor too.

 

[Rich W.]

Just FYI, mine comes up to normal operating temp just sitting idling in about 15 minutes - 190° or so, regardless of outside temp.

 

[Rustymayes]

Just FYI, mine comes up to normal operating temp just sitting idling in about 15 minutes - 190° or so, regardless of outside temp.

Rich, I figured that it should come to temp pretty quick as well. I am going to throw the old thermostat in a pot and heat it up and see if when it opens since the new one is acting similarly. I will also poke around on other Cummins forums and see if I can come up with an answer.

 

[Rich W.]

Rich, I figured that it should come to temp pretty quick as well. I am going to throw the old thermostat in a pot and heat it up and see if when it opens since the new one is acting similarly. I will also poke around on other Cummins forums and see if I can come up with an answer.

I’ve done that little experiment myself, but not for a couple decades - long enough to have forgotten about it. Right up there with putting a flywheel in the freezer and the ring gear in the oven so it will just drop onto the flywheel and then become an interference fit.

 

[Rustymayes]

Well now I am really stumped! I placed the old thermostat in a pan of water along with a thermometer and heated until the thermostat opened. It started opening at 185 and was fully open at 195-200. O took it out of the water and it closed as it cooled. Now I wonder if somehow there is an open cooling loop that is somehow by passing the thermostat. I pride myself of figuring stuff out myself or with the help of the community rather than having a stealership have a tech scratch his balls throwing a bunch of parts and labor at a problem while charging me $200 per hour. I guess this one since Newmar will be paying for it will be an exception.

 

[Buly]

Looks like the heat made by the engine can not overcome the cooling from the cold air blast and cooling from the oil and antifreeze circulation? Some diesel trucks have radiator grill covers for the winter. Many decades ago, we had a Russian car that had luvers for winter use Activated by the driver from the cabin.
Diesels running on 6th gear at 65-70 mph are very efficient = less fuel burnt = less heat generated. Me thinks?
My DS temp gauge stays in 1/3 of scale on the hottest days in the summer.

 

[Rustymayes]

Looks like the heat made by the engine can not overcome the cooling from the cold air blast and cooling from the oil and antifreeze circulation? Some diesel trucks have radiator grill covers for the winter. Many decades ago, we had a Russian car that had luvers for winter use Activated by the driver from the cabin.
Diesels running on 6th gear at 65-70 mph are very efficient = less fuel burnt = less heat generated. Me thinks?
My DS temp gauge stays in 1/3 of scale on the hottest days in the summer.

On a hunch, I turned off the heater loop valves to make sure the heater core was not contributing to the cooling issue. I let the coach run for 45 minutes in the barn. The temps came up to 174 on the digital display but on the temp gauge with the needle scale it only showed 1/4 scale. At the same time my TPM is wacky and my digital RPM reading wildly fluctuates. I understand the electronic engine monitoring on these coaches can be wonky intermittently. I am going to call the Freight Liner Service center in Sacramento in the morning and see what they say.
Rusty

 

[Rich W.]

I’ve had good results with them.

 

[Rustymayes]

I’ve had good results with them.

Good to hear Rich, I have the next five weeks off so hopefully they can get me in for diagnosis soon.
Cheers

 

[Rich W.]

I’ll be headed there sometime after the end of January. Guess I need to call - they are usually 6 - 8 weeks out.