Low Cabin Heat

[NBARSIX]

Greetings. I have a 2000 K3500 6.5 and have always had inadaquate heat in the cab. The cooling system has been flushed w/new stats. Eng temp is good. Im thinking the problem is in the mixing box. Anybody have any experience in that area? Thanks

[DennisG01]

Hello and welcome to the 'Page!

Take a read through this link as there's a number of ideas hashed out along the way that could be of help to you: http://www.thedieselpageforums.com/tdpforum/showthread.php?t=39910&highlight=heat

You said the cooling system was flushed... but was the heater core flushed by itself? I would start with that - flush it right there at the firewall - maybe add some hose so it reaches outside of the engine bay, though (just to make things simpler).

[Diesel 4 blood]

I have had heater cores air lock before and it didn't matter how long we drove the cars they wouldn't work the air out ended up lifting the front of the cars and trucks up with my fork lift and basically burp the system after that heater worked great

[NBARSIX]

Now that I gotta try!! Its weird things like that will surprize you!

[DmaxMaverick]

Just feel the heater hoses. If the engine is up to temp, and the hoses are hot, the problem isn't flow. If they're cold, then it is. Keep it simple.

[DennisG01]

Just feel the heater hoses. If the engine is up to temp, and the hoses are hot, the problem isn't flow. If they're cold, then it is. Keep it simple.

Good idea.

Question... Would this be best done immediately after the engine first gets up to temp (maybe keep the hood open while warming up)? In other words, if you drove around a while, could the hoses possibly feel hot (falsely) due to radiant heat from other things in the engine bay?

Now, just to throw a wrench into things... When I had a low heat problem, the hoses DID feel nice and warm/hot - my hoses still had flow, but it was diminished. I guess it was enough to keep the hoses warm, but not enough to keep the core warm.