mikestock wrote:
I know that in my old gas burning cars the failure of the dash heat to warm up was almost always due to a bad thermostat. That may well be the problem with my 2006 DP, Cat 350 Phaeton. Naturally, changing out a thermostat in this engine is a major ordeal. The dash gage shows the coolant temp to be about normal, in this case I'm just wishing and wondering if someone knows of any other (hopefully simple) defect that can cause the heat to be only mildly warm.
Mikestock,
First, your statement that problematic dash heat in older cars was/is a bit off. In most of yesteryears cars/trucks etc. with either vacuum or manual controlled heater valves, it was those valves that often failed. Especially the vacuum controlled ones. Since they quite often weren't used during off season, as in summer, they'd freeze up. You had heat to them, but not beyond them. Even the manual heater control valves got difficult to move periodically. Yes, a thermostat occasionally went bad too but, they had two ways to go bad.
Now, as for your CAT equipped coach, well, in many cases, there are two, 1/4 turn valves in the heater hoses emanating from the engine and traveling to the front of the coach. They normally are around the oil pan area part of the frame but, they can be located elsewhere too. You don't say if this has been a problem from season to season so, at this point, it's probably not either of them but, it's worth a check to see if they're completely open or, parallel to the frame.
Most dash heat in diesel pushers is not substantially hot anyways due to the length of travel for the coolant. Even if and when the coolant lines are sufficiently insulated, they still cool down some on the way to the front of the coach. You'll still get some heat out of the dash heater but, not as much as a front engine coach. Our coach, an '04 Itasca Horizon 36GD with the C-7 330HP CAT, just took us through some snow covered country in the eastern section of So CAL and the outside temp at that time was 41 degrees.
The dash heater still worked but, even at high speed of the fan, it was not nearly as efficient as say, a car or pickup etc. with the engine up front and heater lines only a couple of feet long. And my heater system is in great shape and, I just changed both "Regulators" (that's what CAT calls thermostats) (and yes, there are two of them sitting side-by-side in the same housing).
My radiator is at peak efficiency too as I just had it out and thoroughly flushed it. So, at this point, make sure all heater line valves are completely open and, with a trusty infrared heat gun, (you can purchase one at most auto parts stores or, even Harbor Freight) and run a check of those heater lines all the way along the coach bottom to see how much heat loss you're experiencing in your particular heating system. And, you can make sure your heater ducts and heater core is also functioning as it and they are supposed to. Rarely do CAT regulators fail. Good luck.
Scott
