My truck I have only see get to operating temperature once and that was with grill inserts install on a 50 degree day on the highway pushing her pretty good. Now that its turning colder it does really even move. Starting to be a pain in the ass since the air it blows is luke warm at best. I have winter grill inserts but I dunno what else i can do? Possibly something wrong? I went to cummings and they said the truck would have came with a 190 degree thermosat from factory. I wouldnt think my thermostat would be stuck open since it warms up a bit but cools down shortly after if left idling. Any ideas?

Thermostat might be sticking open. It happens. Put a infa-red style temperature gun on the thermostat housing. Then put it on the block above or the the side of it to check the thermostat is working. Your coolant is full I assume.

ALSO: Make sure you ONLY buy a genuine cummins thermostat. There is a HUGE diffrence.

when checking the temperatures with the infa-red gun what time differences should i be looking for? Not really following the logic? This just at start up and seeing if the block is heating up faster then the thermostat housing?

Yea coolant is full, not sure if its a cummings thermostat, last resort is replacing it but dont really want to if its not the problem since they are kinda pricy

How long do you have to drive it for it to warm up? My truck will only get up to operating temp on a colder day after about 15-20 miles and that is on the highway, and coming from a 60 deg. garage.

You need to see if the thermostat is opening up at 190 or not. You check the engine block to see what the temperature is, then you see if the thermostat outlet. If they are the same and they do not fluxuate, then the thermostat more then likely is bad. If the engine gets up to around 180-190, then the thermostat outlet gets that warm, then there is a problem elswere.

My truck doesnt warm up untill it hits 12 miles or so depending on how long I let it warm up.

Driving for 30 mins in the city plus little bit of idiling it barely moves. Even when it got up to operating temperature the one time as soon as i let it idle it almost dropped all the way down.

You also might have a bad gauge. Keep that in mind.

Bad gauge was what i first thought but i checked and after the 30min drive to school i could put my hand on the block and it barely felt warm

Codyboy

Sound like you got the classic prob with the dodge heater core stopping up.

First try and reverse the heater hoses going to your heater core if its still flowing some you may get lucky and get it to dislodge, But highly unlikely

Worst case you need to schedule up a date with your mechanic and have the core changed might as well do the A/C evap while your in there since they are very prone to leaking and if you dont your odds are greater with heater core change out.

Me and several others have had this very same problem with our dodges and ctd trucks. It mainly caused by poor coolant flush intervals and crud is allowed to circulate for long periods which causes blockages in the heater core.

I think the last one (heater core & evap) cost a friend right at $600.00 with labor at a local dealer we use. Shop it and see what its running in your neck of woods

I know my heater doesnt blow real hot and it doesnt seem to have the volume it should. More chance of it being a heating core you think?

I know my heater doesnt blow real hot and it doesnt seem to have the volume it should. More chance of it being a heating core you think?

Chance is big that a plugged heater core is indeed causing that. Sounds like your heater control valve is stuck, so coolant flow is restricted. Poor coolant circulation will cause heater not to blow hot air especially if your water pump (http://www.partstrain.com/ShopByDepartment/Water_Pump) vanes are already corroded.

I replaced the tstat in my 99 24v a month ago. Similar symptoms, it really never warmed up, and cooled quickly. A new tstat cured it.

His heater core may have issues, but it's the tstat that does need to be replaced.

What year truck.

replace the thermostat. just had the same problem on my 01 and a new thermostat cured the problem

its a 2002. Gonna pull the thermostat and see if thats the problem. Hope so. I noticed the coolent in heating up. My rad hose to the thermostat was warmer then the sild of the block. So my money is on the thermostat

I had a stuck t-stat and it was the same as you describe. Changed it out and problem solved. The heater core wouldn't cause this problem as it has little to no effect on the water in the block. If it was just cold air into the cab, then it would be the heater core but since the motor itself is not warming up, I'd say the t-stat.

I got no heat in my truck (90) changed the t-stat and nothing so I just figured it's the plugged heater core... winter project!!