Fueling around

3" of snow is a call in? I'll trade you our weather. Forecast of -20°.
Then you can complain about a cold truck...

isu elvi

Having the same problem on my 99. Engine will get to 180-185, but after an hour and a half on the highway, just barely blowing "cool" air. How does one go about unplugging a heater core, or is it a replace only.

Patriot1

i had the same problem took out the heatercore sent it out and it was fine. New stat and gasket and still little heat! I built a shield for my grill and i can roll around day and night and have 190 with the temps outside at 0 to negative 5. But i also tapped the rear of the head as well and got alot of heat out that way as well. The back of the 5.9's don't move water as well and once i did that my truck became a hot box. Good luck!

boughtadodge

Drain the radiator down a little take the heater hoses off at the block and then take a garden hose and flush it out with water from the hose. Flush it both ways this will usually open it up enough to allow heat. It could also be your blend air door not opening.

isu elvi

Just took the truck out for a spin. Its about -5 with wind chills in the -20 or better. Had the truck plugged in since noon, started out at 95 degrees drove about 10 miles in 4th gear near 55 trying to get some heat. With cardboard in front of the radiator ( about 75%), was only able to get to 170 degrees, and as soon as I stopped it dropped hard. Popped the hood when I pulled it back in the garage, to feel all the hoses. Heater core hoses were both warm, relatively the same, one slightly hotter than the other, but not significantly, so I assume it is free flowing. Both radiator hoses were ice cold as well as the top of the radiator. Going to get a new thermostat when i go to town tomorrow, see if that does anything. Otherwise, will try the garden hose trick.

I guess I don't understand the tap the rear of the head comment, care to explain.

Thanks,

Kody

we remove snow from a big shopping center. There are like 5 stores and two restaurants. One being Panera bread which opens at 6am. Today i was called in as well had to go in at 4am and got out at 10am we had 3 trucks a skidloader and a 4wheeler. I am running on about 3 hours of sleep because i got called at 10pm last night and my girlfriend wanted me to stay up till the ball dropped.

also. we get some bigger storms that drop 12-20" of snow so these little storms are easy to handle.

dodgeguy71

Both heater hoses being warm to the touch DOES not mean it is working. I've flushed a bazillion heater cores as a GM tech and Dodge tech. On the GMs both being warm to the touch usually meant I was gonna be flushing it. When your engine is 180-200 degree's the inlet of the heater core should be something you don't want to hold onto for very long. I had a laser temp gun I would use and get the vehicle up to operating temp and shoot both hoses. A plugged core usually had about the same temp, don't know why can't explain not an engineer. If flow is restricted in the core it's likely not gonna flow much from the engine block.....because flow is blocked.

Replace your T-stat, remove hoses for heater core at the firewall. Rig up a garden hose attachment that you can hook to one of the nipples for the core. Leave the other one open. Slowly turn on the water. Start with low flow at first. I've had some heater core's blocked so bad it would blow the hose off if you cranked it wide open, usually were the heater core's I ended up replacing because they could not be flushed.

Flush the water in one direction at first, you'll see when the water runs clear and then you can swap it and run it the opposite way until the water runs clear. Reconnect the hoses, top off the radiator coolant, restart and let it warm up to operating temp and recheck your heat.

One downfall of flushing a heater core that has never been flushed.....sometimes flushing it will lead to replacing it. Sometime's it will spring a leak after being flushed. All that crud sitting inside will corrode the interior, seen this several times.

Also, I have flushed heater cores and still not get sufficient heat from the vents even when all else is working as it should. Replaced the heater core itself and heat was restored. Sometimes they are just to plugged up and need to be replaced.

Hope this helps if you have any questions feel free to message me.

Shawn

isu elvi

Did all the above. Thermostat I took out the rubber around the seat was getting brittle and a chunk was missing, allowing the thermostat not to close all the way. Took out a 180 put in a 190. Unhooked heater core, ran water both ways until clear, hooked it all back up and topped off the radiator. Went on about a 20 mile cruise, got to 190 once but took about 19.5 miles to do it, average around 180-185 still, but hey it was 12 below out. Heat seemed better, but wouldn't say it will burn you out of the cab. Will check the anit freeze again and see what it does.

mrclean

You will also want to check to make sure the blend door is operating properly. If it is stuck partly open, you'll never get enough heat in the cab, no matter what the engine temp is.

dodgeguy71

Are those older models manual(cable) operated doors or vacuum? Mr Clean has a point as well.

trust

the blend door on my 01 is electric motor operated, and pretty expensive, and it appears to have either failed or broken again as mine puts out LOTS of heat but only to the dash and defroster, none to the foot wells.....

nickg

Mine is an 01 and blend door is operated by vacuum, usually when you loose vacuum the heater defaults to the defroster,

to the other posters if you can get your truck to 180-190F, and the heater core is good, try blocking the re-circ door open about 3/4 open this allows warm cabin air to mix with the ice cold air before it goes thru the heater core, end result is 2x the heat you would have had previously, as a simple test you can turn your selector to MAX AC and turn the heat selector to HOT, if your core is clean and your up to temp, it will double or better your heat output, down side is it will start to fog the windows as the moist hot cabin air will start to freeze on the windows after 5mins or so.

here is a shot of mine lockwired open, I now can use the fan speed higher than #2 without loosing heat

nickg

here are some more links on the subject

https://www.dieseltruckresource.com/...ght=broomstick

Fueling around

Pre-98 trucks can simply put the fan control on A/C to dehumidify the air. I use my A/C heavily from December to March.

Shovelhead

I took the '99 on a road trip yesterday.
Starting out temps were in the low 20s.
Temp gaguge rose to around 180 degrees, dropped to near the first line, then went no higher.
I was 30 miles away when the heat got more than slightly 'warm' with the temp selector all the way to HOT.
Remember, you are also trying to warm up all the materials (plastic, seats, carpets, metal) in the cab that has been sitting at outside temps all night.
After an hour, the cab was FINALLY starting to warm up as all the materials in the interior were starting to warm up.

When I arrived at the destination, the truck sat outside for 8 hours.

On the return trip, I slipped my cardboard with the 5" hole cut in the center in between the radiator and charge air-cooler.
HUGE difference.
With the temp selector only set to 1/2 way, I was toasty warm within 15 minutes and the temp gauge was hovering in the middle of the range.