Dash heat trouble

[zman62]

07 Camelot. We dont get much heat from the dash. I have checked the mixer valve on the firewall. I took it apart because it was sticking. It got better for a while but now it s barely warm. It looks like the valve is moving all the way to heat but hard to tell. Also we have a cool breeze hitting my right foot while driving. I bought some spray insulation yesterday but not sure where its coming from. Nothing worse than a cold right foot on a long drive.. Any input would be great. Thanks!

[86 Cavalcade]

I replied back on 10 Sep 2010, at 12:30 pm, about the problems I had with my dash heater, air conditioner, and cold draft problems. It is in a posting about Dash blower motor resistor locations. George

[HeapBigEngin]

I admit I am not sure if a Camelot is a DP or not. If it is, I might suggest you look at the two valves back at the engine that control coolant flow forward to the front heating unit. On my Cummins equiped DP, the outflow valve over time would vibrate to about a 1/3 open poistion, severely restricting flow. I fabricated a small clamp to hold it open and presto....more heat. I close both valves in the Summer to aid the dash a/c operation. You might want to take a look at those valves if you have a diesel.

Re the air leak, do you or a neighbor/friend have a good-sized fan you could place in front of your unit. Perhaps it will generate enough air flow to identify the leak location. Please let us know what you eventually find out....thanks.

[zman62]

Quote:

Originally Posted by heapbigengin I admit I am not sure if a Camelot is a DP or not. If it is, I might suggest you look at the two valves back at the engine that control coolant flow forward to the front heating unit. On my Cummins equiped DP, the outflow valve over time would vibrate to about a 1/3 open poistion, severely restricting flow. I fabricated a small clamp to hold it open and presto....more heat. I close both valves in the Summer to aid the dash a/c operation. You might want to take a look at those valves if you have a diesel. Re the air leak, do you or a neighbor/friend have a good-sized fan you could place in front of your unit. Perhaps it will generate enough air flow to identify the leak location. Please let us know what you eventually find out....thanks.

Its a Cummins ISL. Where are your valves located? I have never noticed any when I have been in the engine compartment.

[86 Cavalcade]

My MH is a 2001 40' Diplomat with a ISC 330 Cummins, and I have been all over the engine trying to find some type of shut off valves and I have never been able to find any. I replaced the electric operated valve on the front firewall and that did not help at all. I put a straight piece of tubing in place of the electric valve and even reversed the the heater hoses, none of this made any difference. I finally noticed that my heater box was broken at the top and had pulled away from the firewall bypassing the heater core and the evaporator core as well. I have pictures in my old posting about this repair. I have a 175 thermostat in the engine at this time and I am going to go to a 190 or so the next time I change it. I asked the local Cummins dealer if going to a hotter thermostat would harm the engine and he said it would not. It makes you wonder though why did Cummins put these 175 thermostats in. Even though I did all of these things as well as putting an electric circulating pump in the heater supply hose which helped more than anything except for bolting the heater box back to the firewall, you are still not going to drive down the road naked if it is below about 40 degrees outside. George

[HeapBigEngin]

Not sure if this applies to both situations, but I have a Cummins 8.3 ISC with side mount radiator in our 2003 40' F/Wood Revolution DP. It has 2 valves at the engine that control coolant flow to and from the front heater system. BOTH valves on my MH are on the driver side. I must get on my creeper and roll under the coach on the driver's side to open/close them. The lower one is along side the engine and hooks up to the radiator plumbing located there. It is easily visible. The other valve is just a bit further forward and up above somewhat and, if I remember correctly, taps into the cylinder head. That one is more difficult to reach. It's the lower one on mine that used to vibrate downward and restrict flow. I would have to crawl under and refresh my memory which valve controls forward flow and which controls flow back into the motor. I think the bottom one on mine controls forward flow....not sure.

Suggest when you are under there, locate the 2 coolant hoses that go to the front....and then follow them back to the engine. You should find the valves. I would be amazed if you don't have them. If a leak develops up front, one would think that there would be valves to close that part of the system off so that all the coolant for the engine, some 30+ feet away, would not be lost. I am not sure that this is your problem, but it sure would not be difficult to rule out these valves. Just my thoughts.....