caver77

Taking any suggestions and recommendations in regard to my no cab heat situation. Here's the thing : Engine warms up to operating temp in what seems like a normal manner, blower works fine(decent air flow), recirc door is operational, blend door moves fine and when I had the actuating motor off seated in either direction without resistance(telling me the door isn't broken), when I turn heat selector **** blend motor moves in what appears to be a proper relation and loads up signifiying to me complete travel, visually inspected with light and mirror blower motor side of evaporator/core revealed relatively clean condition, coolant level appears to be proper level, coolant lines into, and away from heater core get almost too warm to hold when the truck is warmed up(telling me there is some sort of flow through the core), but no heat in cab. What am I missing !?! Last thing I did was take off the blend door motor to see if the coupler was broken, but it wasn't. The heater core was flushed about two years and there was no debris to amount to anything and flow seemed alright in either direction. This has been going on for about two years now . The ac works fine and isn't on. Please, any advice out there.

pind

look at the outside of the heater core.

Thanks in some small part to our friendly neighbourhood emissions laws, that puke bottle under the hood, not only causes the rad to gum up, it causes the heater core to do the same. Not much vapour for the core to get, but the fan manages it, and over the years, it adds up.

I have to do the core in my 01 in the near future, but with a borescope, I have seen how munged up it has gotten over the years. Still has half decent airflow, but no where near as it should be.

caver77

Well, I did check the blower side(easily accessible side) and it was quite clean still, I blew it out with a bit anyways in case it was dirtier than it looked, I guess the other side might be a different story because I couldn't see it. What make/kind of bore scope were you able to get it there and what way did you route it in to get a look at the heater core? Thanks.
P.s. ya no kidding about the puke bottle I use take my rad out ever 2-3 years to give it a good cleaning, finally a while back I just put a put a piece of hose on it and ran it down by the axle, has run pretty clean since.

pind

I used the hose down to the axle at one point, it works in the summer, but in the winter, it would ice up frequently. I finally gave up on it.

I can't even recall where I went with the scope at this point, I'll have to fish in there one of these days, when I have a minute, and figure it out again, if I don't simply pull the core first

nickg

wrong type of thermostat will do the same thing, or more likely heater core is plugged,

as for thermos the Stant on the right would get to 190* on the gauge but would not direct enough coolant thru the heater core, the OEM stat from cummins fluxiates more 180-190, but makes a huge difference in heater output. I tested mine the other day and idling at 1200RPM and engine at 185* I get 41-42* C at the drv side heater vent,
have noticed I dont seem to get any noticable heat until engine temp is over 140*F..
I have an after market heater core, and I believe its not of the best designed

caver77

Did replace the stat with a napa one about 5 years ago. The factory one had become inoperational and I couldn't get any engine heat at all. Replaced it and everything seemed good, at the time it didn't seem to affect the heat in the cab. I guess the thing that puzzles me is that the hoses in to, and out of the core are hot. Guess I start with either buying a scope or replacing the stat. Getting tied of being cold. Gonna have to start running my camping stove in the thing if I can't get this rectified,not .

gorms

Try flushing the core through the lines under the hood. Has the system ever been flushed? Truck is almost 9 years old....

Copenhagenjunkie

I would do a heater core flush again going both directions and get a new cummins thermostat.

I have poor heat too when it's below 0. I am not pulling the heater core unless it leaks. Added a 12v heater to pass side floor area to keep wifes feet warm. If I can keep temps @ 190+ the heat is good enough.

FYI, I have hot heater hoses too- probably restricted flow.
ADD: or more likely not enough air movement but sure feels strong and keeps window melted in cold weather.

caver77

Ok, I'm gonna try and flush things both ways again, is there any specs for the flow one should get through the heater core(volume/pressure/time), then think about the either buying a new stat or scope for doing a visual on the heat side(hate the idea of ripping the whole dash out just to check on core condition when I'm getting reasonable air flow and it looks good from the blower side).Will check back in with an update later. Out of curiosity does anyone know off hand if they manufacture a small scope(small and flexible enough to fix in through the trucks heating system) with a ir thermometer incorporated?

caver77

Got some time to try and flush the heater core today ran about 4-5 minutes one way and then the other. No pieces, or chunks or any thing, just a very slight discoloration. Topped up the coolant in the core hooked it back up and low and behold it's got a bit of HEAT now which still suprizes me,can't hardly believe it((is that all that usually washes out in a flush?(the first time I did it years back there was nothing), and it can make that much difference?!)). Thanks for talking me into doing that guys. I guess I'll pick up a cummins thermostat tomorrow and hope that it gets it to heat up the rest of the way . This should have happened along time ago.

sixguns

Replaced my heater core last winter and cut the old one open it was full of crude, probably had half flow.

dangina

what do you guys use for floor heaters? it just takes too long to heat up the cab...

Midnite

I looked for 12 volt cab heaters, but everything I found was incredibly wimpy. Part of the problem is the power draw for anything that would put out significant heat.

I just replaced my thermostat with one from genosgarage.com and I get *much* better heat now, and far sooner than before.