2nd Gen Non-Engine/Transmission Not hot enough

[AMatsonIII]

Well I know it is cold out here in New England, but my heater is not working like it usually does. Seems to be blowing cooler. Temp is 185still cool put cardbouard in front of radiator still 185 still cool. Pulled dash heater core is hot. Flushed it out still cool. Checked blending door opens and blows cool air then turn it to heat and it warms up but still cool I am not sure what is going on usually blows hot just doesn't seem to be working properly. SOrry for the long thread any help would be great thanks

alex

 

[AMatsonIII]

Fixxed

Well Thought is out long and hard. Everything checked out with a temp gun. I guess it was just too cold. So I got thinking If you can recirc when the a/c is on to get it colder why cant you recirc the get it hotter. So i removed my glove box and disconnected the vaccum accuator arm from the door. Then after screwing around with a coat hanger trying to keep the door in recirc, I grabbed a tiiny bungee cord and it is now open. Unbelievable difference in the temp. Truck starts pushing out heat quicker and it now drives me out to the point i have to turn the heat down. Even if i turn the mixing door to cold the warm air from the cab still blows warm. Hope this might help someone else out.



Alex

 

[jelag]

My trucks sit out in low temperatures... at below -20*F we might not be able to keep the cab really warm, when driving at 50 mph... below that no problem... .

We have found that a little bit of air in the coolant system will hinder the heater... and something as simple as a quart of air instead of coolant seems to end up in the heater core and starve it... .

We are careful not to allow the coolant to get low... . and we don't change it... . but if we have a hose off, or change a water pump we have to really work hard to burp the air out... .

My wifes car has a port on the top of the engine for this... it looks like a bleeder for the brakes... I don't know of such a bleed port on the Cummins... . what we do is bring the truck to temperature with a coolant pressure tester installed at 12 lbs pressure and pump the upper hose... compress it with 2 or 3 hands... and that tends to work the air through... . once it burbs all is well...

Hope this helps...

 

[Joe Mc]

I was just about to post the same question. Today I borrowed the infrared thermometer with the optional pipe wrap plug in thermometer. I stuck the plug in probe into the duct on the drivers foot area and drove on down the road, after engine came up to normal operating temp I checked the floor probe reading on the display, with the fan speed low and temp dial to hot it read 116*. As soon as I turn the fan speed up 1 notch the temp dropped to like 85. These temps sound nice and warm but my feet are freezing! I shot the laser sight on my foot and the temp read 52* - this was w/fan speed on low. Same temps coming out if I switch duct control to dash outlets. I've had this truck since 01 and never remember it being this cold inside. In Sept the t-stat failed, I put a new one (Cummins $$$) in it so maybe there's an air pocket??? You think it would have worked it's way out by now though, I check coolant level every week or two and it's been fine in the rad and tank.

All I know is I'm freezing my tukuss off going to and from work and it's too cold outside to work on the blanged thing - I love the winter otherwise. . . WAAAAAAAAAAAH!!! BRRRRrrrrrr

 

[Beach]

I had bad heat issues last winter. Cool/cold air blowing out, all the blending door's operated normal and heater core and lines in the fire wall were all getting hot. I finally couldn't take the cold any more and numb fingure's and payed someone to fix it. Found out the heater core was plugged on the outside with dust and those fuzzy thing's off the tree's. I had the guy replace my leaking a/c condensor while he was in there. Blow's hot now! Good luck with your's.

 

[AMatsonIII]

Ya I drove about 120 miles tonight. with my new trick and the heat drove me out. So i don't know what the issue is but for now this inexpensive trick wil work for me. I will look into it further in the spring when it is a little warmer out

 

[dseabaugh]

maybe the blend door doesn't close all the way from the factory to prevent you from being gassed with exhaust fumes??? Any air you bring in from outside has to be brought up to temperature to get warm. I had to put in a new thermostat Saturday ( from Cummins Mid-South part number 3928499, $35. 39) . The original factory one stuck open. Air didn't get warm in 50 miles. They didn't have the thick , square cut O Rings needed to replace it and I spent all day trying to find them. Finally got 2 at autozone, One right & one wrong, so I had to use one original Oring from back when the truck was built in 1996. The new thermostat doesn't run near as warm as the factory original one and still does the swing back and forth thing, just at a lot lower temp. . .

 

[Joe Mc]

Did the trick as soon as I got home from work yesterday, since it was finally not too cold to work on the truck. Litterally took 5 minutes to disconnect arm, pull vac line from actuator and plug, then wire tie arm for door down so the door would stay closed. I drove around the bolck a few times and it seemed to be warmer.



Didn't really notice any difference on the way to work this morning so I'm not sure yet? I hope I don't have a restricted air side on the heater core . . .

 

[Missouri Mule]

There is jiggle pin to let the air out on top of the block toward the front.

 

[2-ND TIME]

Not enought heat

When you recert heat you aren't getting any fresh air into the cab and that will cause the windows to be fogged up most of the time. If your engine isn't putting enought heat to the cab, I cut and fit a 24"x24" mudflap under the engine and tied most of it up to reduce the cooling of the engine it helped. It's never burned enought diesel to make it hot!