Chasing heater inop Cat 3126E engine

[Jim15599]

I have a 2002 national tradewinds 7390 model motorhome it's on a Freightliner XC chassis with a Caterpillar 3126 e engine I am getting no warm air to the front heater core to use through the dash unit I have found one valve back at the engine but some have an indicated there are two any help on this would be appreciated it does have an electronically controlled water valve that I do not know how to test have not pulled the valve yet to physically see if it opens thanks

[ernieh]

I once owned a 2003 FL/3126 chassis. It had two shutoffs back by the engine. Another possibility is that your coach has a separate vacuum pump to control the heater/ac. That's what my Winnebago had and they seemed to have a lot of issues, mainly with the hose connections breaking.

[rangerb3]

My coach is the same...My manual valve is on the drivers side just forward of my engine oil filter. There is a cable actuated heater valve up front where the hose goes into the evaporator that I removed and installed another manual valve which I only open for winter driving.

If your heater valve up front is electrically actuated you could take a small 9v battery to test it to see if it's actually opening when it gets ship power.

[zproud]

Check the lines to the heater core on right front by generator, are the warm/hot?

A diesel pusher has to move the coolant 35 to 40 feet,,, when real cold.. the heat output of the coach engine heat is meek at best, I would run a separate 110 heater.. or run the propane heater to stay warm....


Best of luck!

[Skip426]

Freightliner installs two shut off valves , beside the transmission , one heater hose off the water pump , the other off the back of the cly. head . The hoses off the engine are 3/4" the rest of the chassis is 5/8" . The shut offs are about a foot apart in the area of the trans and air system dryer.