Very little heat from dash heat registers while underway

[Rustymayes]

The last few times we had the 4081 DS out I am sure we got adequate heat out of the dashboard heating, as a matter of fact my wife complained that it was too hot. This weekend we took the coach up to Feather Falls Casino and RV resort and drove most of the way in rain and temps in the low 50s. I noticed that with the heat up high I only got barely warm air out of the registers. I checked the engine temp and was surprised to see temps only 115 to 125 degrees F. I would have expected 180 to 200 plus but being new to the DPs I am wondering if this is normal. Then I was wondering if the Oasis heater should be supplying hot water to the dash heat system as it was on. Any insight would be helpful. I am thinking I may have a thermostat issue with only 3600 miles on the coach I would be a bit surprised. While on the subject of possible engine issues I noticed that my Serpentine belt that drives the radiator cooling fan angle drive is squealing. I replaced it with a belt that I bought from a local discout parts house instead of going with Cummins supplied belt. I think the belt was an inch shorter and last weekend after an 80 mile run I noticed that it had shredded one groove off! I put the old belt back on to get home, ran some bar soap on it and the squeak went quite for a few minutes then came back. I plan to replace it with another Alliance OEM belt but wondered if perhaps this is a common issue with the Diesel pushers due to the dirt and grime that coats everything in the ER.
Thanks for the input.
Rusty

 

[RandyB]

I have found that with the controls in "fresh air" position, the air inlet door for the HVAC is wide open. It is under the hood and is in direct contact with the air rushing in from the grill area while under motion. This is what has contributed to cooler than desired dash temps as well as infiltrating cold air during the off periods (while camping).

My solution is to operate the controls in the "recirculation mode". This closes the air inlet door and has improved dash temps during cold drives.

 

[Dan_Frisbie]

If your engine water temperature is not up to proper temperature, it is very likely a bad thermostat.
Contrary to what many people think, a faulty thermostat will usually be in the "open" position and not allow the engine to build sufficient heat, therefore not heating water enough to keep you warm.

 

[widdershins]

+1.. first thing to check...and super easy fix if it's bad.

 

[Rustycoach]

I have found that with the controls in "fresh air" position, the air inlet door for the HVAC is wide open. It is under the hood and is in direct contact with the air rushing in from the grill area while under motion. This is what has contributed to cooler than desired dash temps as well as infiltrating cold air during the off periods (while camping).

My solution is to operate the controls in the "recirculation mode". This closes the air inlet door and has improved dash temps during cold drives.

Thanks! I will confirm but I am pretty sure the recirculating air button is pushed as the button was lighted blue. I will look into the thermostat as the culprit.
Thanks for the input

 

[Rustymayes]

I bought a new thermostat. I am looking for any insight as to issues with draining the system of antifreeze. I plan to just drain a few gallons from the radiator petcock since the thermostat is above the level of the radiator there is no reason to drain the entire system. I see some specific instructions on the expansion tank for refilling the system that speaks of closing heating system valves and such. Any of you guys dealt with the cooling systems on these units? If so and you have any tips to avoid headaches would be appreciated.

 

[Rustymayes]

I installed the new thermostat yesterday, Not a huge PITA. I love the jack system? it is nice to be able to rais and lower the coach to aid in access. I removed the surge tank to make it easier to access the thermostat housing. After the replacement and replenishment of the antifreeze, I ran the coach for about 45 minutes without actually driving it. The temps only came up to 135 degrees on the gauge. I used a digital thermometer and shot several areas on the cooling system and found everything running quite cool. Highest reading was 156 at the surge tank. I guess I will take her out for a run later today and se what it does with a load on her. I would think that 45 minute would be plenty of time at high idle to come to temp though.

 

[JRS]

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.

 

[Dan_Frisbie]

You gotta. Put a load on the engine to build any real heat.

 

[Rustymayes]

Well I took her out for a little run, town and freeway and country roads. only about twenty miles with day time temps at 56 degrees in full sun. I still only registered 145 on the instrument panel gauges. I shot the engine area with the digital thermometer and the highest reading I got anywhere was 156. I can't imagine the engine did not have enough time to get to temp. I really don't want to do damage to my engine by operating with too low of temp but kind of running out of ideas. I guess I will call Newmar and open a warranty ticket and let them figure it out.