Heater core.

[Denalibro76]

Hey all, apologies if this is a stupid question but it’s that time of year that it’s damn cold here in my part of Canada and my Yukon doesn’t seem to warm up. It could idle all day long and only get a quarter of the way to normal temp on the gauge. Interior temp also lacks until it’s driven for 10-15 minutes or so. Replaced the water pump and thermostat 2yrs ago so that shouldn’t be the issue? Maybe a flush for the heater core? I realize it’s cold so a little lack of heat is expected but just seems like it should be a little better.

 

[Doubeleive]

Hey all, apologies if this is a stupid question but it’s that time of year that it’s damn cold here in my part of Canada and my Yukon doesn’t seem to warm up. It could idle all day long and only get a quarter of the way to normal temp on the gauge. Interior temp also lacks until it’s driven for 10-15 minutes or so. Replaced the water pump and thermostat 2yrs ago so that shouldn’t be the issue? Maybe a flush for the heater core? I realize it’s cold so a little lack of heat is expected but just seems like it should be a little better.

interior heat will be directly related to the vehicle temp, so in other words even if the heater core was completely ***** the vehicle would still get up to normal temp.
fix the vehicle temp 1st then if it is still not getting warm inside check the blend door actuator, heater core being clogged is last on the list of possibilities

 

[tungsten]

Mine has no problems getting to 100c in -20 temps.Now driving down the hywy it will drop a little.
Put a hotter thermostat in.Maybe you put a summer one in?
Flushing heater core has always helped on older units,the amount of goo build up is crazy.

 

[Fless]

What year Yukon?

Based on what you said it sounds like you've had this truck for a while. Did it warm up good last winter? Or when did this problem start? Any recent work done to the cooling system? (New radiator, etc.)

What @Doubeleive said, the engine needs to warm up to produce heat in the cab. If the thermostat is an unknown value, or if it's not the OE temp, then it may be time for it to be replaced.

 

[Denalibro76]

What year Yukon?

Based on what you said it sounds like you've had this truck for a while. Did it warm up good last winter? Or when did this problem start? Any recent work done to the cooling system? (New radiator, etc.)

What @Doubeleive said, the engine needs to warm up to produce heat in the cab. If the thermostat is an unknown value, or if it's not the OE temp, then it may be time for it to be replaced.

It’s an 03’ 6.0. I haven’t done any other work to the cooling system aside from the water pump. It had this issue even before I did the work so I was hoping that the new thermostat that came with the new pump would fix the issue. Maybe it’s just a case of it is what it is?

 

[Mudsport96]

Being an 03 it is highly possible the radiator has been replaced. If it wasn't a gm replacement it is likely the port that goes from the radiator to the expansion tank does not have the correct restriction orifice. That daughters Silverado had this issue. So i pulled the hose loose and put a 45 acp case minus the primer in the hose and clamped it in place. It now heats up properly.

 

[Denalibro76]

Being an 03 it is highly possible the radiator has been replaced. If it wasn't a gm replacement it is likely the port that goes from the radiator to the expansion tank does not have the correct restriction orifice. That daughters Silverado had this issue. So i pulled the hose loose and put a 45 acp case minus the primer in the hose and clamped it in place. It now heats up properly.

Ok good to know! Thanks! I’ll do some checking. I’ve only had the vehicle for 7ish years or so. 230k miles on it.