Here's the scoop. It runs through my mind every winter. Is everyones like this or is my thermostat stuck open.

20-25 degrees this morning. Plugged in overnight. Remote start in drive.
Idles a full 15 minutes. Coolant temp 98. No cab heat.
Drive 6 miles to daycare. Coolant temp 163. Luke warm heat.
Idles at daycare for ~5 minutes. Upon leaving colder coolant temp 143. No heat.
Drive 3 miles to work. Coolant Temp 165. Luke warm heat.

Me? Frozen to the core....

edit: I put plexiglass over the radiator last year and it didn't make a bit of difference.

 

My heater will run me out of the truck once it gets up to operating temp.

I start feeling heat when the gauge just starts moving.

Perhaps you have a blend door issue?

 

I would agree with you except that the temp itself isn't moving. No temp - no heat regardless of blend door. Plus the blending seems to be ok. I can hear it move and close.

Seems the truck should get warmer then 120-140 idling for 15 minutes. By the time I get to work that truck has been running close to a half hour or better.

 

Is the high idle feature turned on? Mine isn't, but between being plugged in and sitting in there holding the rpm's at about 1100 or the preset idle feature holding it at about 1000rpm's, my truck warms up enough to get warm air flowing in about 12-15 minutes, give or take. Temps are in the 20's here as of late.

 

Yes. It's in high idle when I get into it in the morning. I have to think MY and Michigan are seeing the same kinds of temps these days. 20's is about right. I'm willing to bet, because it gets colder idling, that it could idle all day and never get past the 140 mark. That doesn't seem warm enough to give me heat. I don't get much heat till the 175 mark, just luke warm air.

 

gpshemi,

Just idling the truck will not get the truck up to operating temp (190-210 degrees F). In fact idling allows the engine to cool. The truck needs a load put on it. After starting the truck and allowing the oil pressure gauge to swing to the right I use the full defrost setting (**** all the way turned to the right) and turn on my fan on the lowest setting. This kicks on the compressor and puts a very, very small load on the engine, none the less a load. I then kick on my exhaust brake and this really heats things up. In about 5-7 minutes the exhaust brake kicks off after it reaches 170 degrees F. I then drive the truck still in the full defrost setting to finish getting the truck up to temp. Once its there I switch the setting to the dash/floor mode. I too cover my grill with plexiglass to keep the cold air out. I think it helps. You could at least try my suggestions (exhaust brake excluded, unless you have one on your truck) and see if it helps.

 

I set the defrost the night before. So it starts that way.
Wish I had an exhaust brake. Would be handy for the 5th wheel too.

I'm going to check the upper hose by hand tonight when I get home to see if it's at all warm to the touch. I bet not though.

 

T-stat problem. Don't worry, I already had to replace mine twice. Once due to a fluctuating temp gauge and the other it took forever to warm up on a 10 deg day and cardboard in front of the radiator.

 

That's what I'm thinking too. It's stuck open despite what the dealership says. Not getting warm hardly at all just doesn't seem right.

Are they easy enough to change or do I have to stand on my head. Never wrenched on a Cummins....

 

I'm sure you checked the coolant level in the over flow bottle??


They are easy to change. Just drain about a gal of coolant from the radiator, remove the 3 bolts that hold the neck (you can leave the upper hose attached to it), then pull out the t-stat. When you go to purchase a t-stat, don't pay less than $20 for one, you'll run into more issues than they're worth. To be safe, get one from Cummins if you got one close by, otherwise, you can get one from Napa. I'm running one, and so far no problems yet.

 

I think it is an early model megacab thing. I know a couple people with early model megas having the same issue. my 09 might as well have a fire on my face and feet..... it is too hot when I have it turned up all the way..... Even when it is 20-30 in the mornings it takes about 2 miles from the time I leave my driveway for it to be blowing flames at me. I dont have remote start nor do I preheat my truck before leaving..... My A/C works great up to about 105 so far also...

 

Are you using a winter front? I am on my Mega Cab and I turn the heat blend switch to the 6.0 clock position and sometimes to the 4 or 5 0 clock position, after we reach operating temps. This will occure in two miles on mine at 20 deg F.
The fan never runs above the first speed and I usually have the blend doors bring in outside air in the upper vents. I believe the winter front gets the truck up to operating temp quicker and keeps it there.
When we travel on long trips no coats and just a shirt or light sweater.
I would suggest that you look into a winter front for your truck.

 

I had a similar experience with a 2006 3500 mega cab... no heat on cold mornings (ok... I'm in Georgia, nothing like you guys are getting). It happened a couple of times but after stopping for a few minutes, I'd get in, fire it up, and the heat would work.

Then the real problem began... No heat and the engine temp would move to the red. I changed the thermostat... took all of 15 minutes. It's a very simple change... I did it at our campsite with only the tools I with me. The housing is on top of the block and really easy to reach. Three bolts (8mm I think)... no felt or paper gasket... just a rubber seal that comes out with the old thermostat and is already attached to the new one. Pull the old one out, put the new one in, top off with fluid.

Heat works fine now. The truck doesn't reach operating temp while idling... it has to be driven a couple miles. Not a problem... I like driving it!

 

well it was -15 this morning on the overhead in wolfcreek/pagosa springs CO. my heater was still blowing fire in our faces within 5 minutes of turning the megacab on. I actually have to turn the heater down to where the blue and red on the dial are mixed..... stock truck......

snowboarding is great, powder is almost rediculous.....