Its So Cold!

[elcompalaline]

So the temps are starting to drop out here in OR (in the 30's early in the mornin) and I start the truck with remote start and had left the heater on the previous evening before shutting it off. So I hop in when ready to go to work and its blowing cold air! Double check the settings and everything is where it should be and nothing, so I need to go and figure it will warm up on the way. It did slightly but not much and I'm stuck. Whats the issue? While sitting and idling it won't warm but once I start moving it starts heating a bit, and If I stop moving I'm back to blowing cold. If you guys would help out I would greatly appreciate it, thanks in advance.

[Spurshot]

How's the engine coolant temp?

[elcompalaline]

How's the engine coolant temp?

 

Normal, at first cold of course (in the morning) but I left me truck running for almost an hour yesterday afternoon with outside temp of 76 and its still didn't heat up.

[txab]

Is system full of coolant with no air trapped in it?

[elcompalaline]

Is system full of coolant with no air trapped in it?

 

I would think so, haven't messed with it at all. Changed the oil last week and checked the fluid levels too and they were fine. The coolant is relatively new too, had the system flushed and replaced fluid at dealer about 4 months ago. How would air get trapped in there?

[Daryl LBZ]

Is system full of coolant with no air trapped in it?

 

I would think so, haven't messed with it at all. Changed the oil last week and checked the fluid levels too and they were fine. The coolant is relatively new too, had the system flushed and replaced fluid at dealer about 4 months ago. How would air get trapped in there?

 

 

Air is just a normal thing that happens when the coolant is added or replaced. If not bled properly it could do a number of things. Did the dealer bleed the system of air?

[grayghost7]

Is system full of coolant with no air trapped in it?

 

I would think so, haven't messed with it at all. Changed the oil last week and checked the fluid levels too and they were fine. The coolant is relatively new too, had the system flushed and replaced fluid at dealer about 4 months ago. How would air get trapped in there?

 

 

Air is just a normal thing that happens when the coolant is added or replaced. If not bled properly it could do a number of things. Did the dealer bleed the system of air?

 

 

Shouldn't be an air issue....sounds more like a thermostat/heater core issue to me.

[Spurshot]

Bleed? I was not aware of a bleeding procedure for the coolant system other than fill it, run it, check it.....

[elcompalaline]

Is system full of coolant with no air trapped in it?

 

I would think so, haven't messed with it at all. Changed the oil last week and checked the fluid levels too and they were fine. The coolant is relatively new too, had the system flushed and replaced fluid at dealer about 4 months ago. How would air get trapped in there?

 

 

Air is just a normal thing that happens when the coolant is added or replaced. If not bled properly it could do a number of things. Did the dealer bleed the system of air?

 

 

Shouldn't be an air issue....sounds more like a thermostat/heater core issue to me.

 

 

That scares me! The last thing I need is to have to take it in to the stealership!

[grayghost7]

Bleed? I was not aware of a bleeding procedure for the coolant system other than fill it, run it, check it.....

 

There's really not one. I have heard distant rumors of bubbles in the upper hose, but never have seen first hand evidence. I just flushed and filled mine recently with no issues.

[Spurshot]

Bleed? I was not aware of a bleeding procedure for the coolant system other than fill it, run it, check it.....

 

There's really not one. I have heard distant rumors of bubbles in the upper hose, but never have seen first hand evidence. I just flushed and filled mine recently with no issues.

 

 

 

I have experienced gurgling in my 99 2500 when coolant gets low. I just add water and it's fine again.

[Daryl LBZ]

Bleed? I was not aware of a bleeding procedure for the coolant system other than fill it, run it, check it.....

 

 

Yea used to have to bleed it all the time on my 88 GMC. On it you would leave the radiator cap off while the truck ran and it would bubble coolant out until all of the air was out of the system. On my Camaro it acctually has bleeder valves that you just loosen and tighten until all the air is out of the system. Probably different on the new truck though because I don't think there is a cap on the radiator I think it's a closed system right?

[Pilot12]

Shouldn't be an air issue....sounds more like a thermostat/heater core issue to me.

 

The only time my heater core went out on me, it leaked coolant under the truck. But that would cause your symptoms. If your water temp guauge is normal, heater core would be my guess.

 

I hope you post the results when you get it figured out. Thanks!

[txab]

Bleed? I was not aware of a bleeding procedure for the coolant system other than fill it, run it, check it.....

 

That's what it basically is. But some people are uninformed and just fill it and go.

 

Tech Wiki

[Spurshot]

On old GM cars/trucks, there was a valve that was vacumn operated to open and close the water flow from the engine to the heater core. I can remember a few cold nights getting out of the car on the side of the road and manually turning that valve because it was rusty and stuck.

 

I would guess that there is a valve that performs that same function, but maybe up in the HVAC assembly. Also, there is a door that mixes the heated/cooled air of the HVAC system. This door seems to be a problem with some of the guys around here.