2000 Yukon..Heat issues

[ARogg619]

Good Morning All,

So I have this 2000 Yukon I bought as my winter ride / work beast. As its getting pretty cold now, ive been using the heat and lately the heat from the dash is just WEAK. it takes forever to get warm if it even decides to. Now, my rear heat is perfect and warms up just as you would expect. Where should I start with diagnosing this because I want to figure this out asap before its really cold? This is frustrating bc I bought it for winter and to give my Camaro a break but I wound up taking the cover off the Camaro this morning and taking it to work after giving up on the defrost trying to clear the windshield for over 15 minutes. The truck gets up to temp just fine and no overheat issues or anything like that.

Appreciate any help,

Adam

 

[Scottydoggs]

if the fan is blowing on full ok. id think the heater core has air trapped in it.

take the coolant tank cap off let the engine run and top it off as needed. can take a little while for it to burp and bleed out the air.

then check the heater hose connections at the firewall for a small leak. as well as the other hoses. fix as needed.

 

[ARogg619]

if the fan is blowing on full ok. id think the heater core has air trapped in it.

take the coolant tank cap off let the engine run and top it off as needed. can take a little while for it to burp and bleed out the air.

then check the heater hose connections at the firewall for a small leak. as well as the other hoses. fix as needed.

Yeah, the fan blows fine, just not hot. ill let the truck cool down and check my levels. I know I don't have a leak bc I have a brand new driveway with zero spots on it ( for now lol )

 

[Joseph Garcia]

Is it possible that the valve controlling the flow of hot water to the front heater core is not functioning? With dual heat zones, I am assuming (maybe incorrectly) that there are two separate hot water control valves, one for each heater core. Folks with more knowledge than me in this area will chime in.

 

[OR VietVet]

Check the flow thru your heater core. Both hoses, when engine is completely warm, should be about the same temp and hard to hold on to with a bare hand. If they differ in heat then the heater core is clogged. If it is clogged then change the thermostat as well, at the same time.

 

[ARogg619]

Check the flow thru your heater core. Both hoses, when engine is completely warm, should be about the same temp and hard to hold on to with a bare hand. If they differ in heat then the heater core is clogged. If it is clogged then change the thermostat as well, at the same time.

If its clogged, what is involved in clearing It out?

 

[OR VietVet]

If is clogged make sure you don't listen to someone who says, "flush it out". A flush is for maintenance and not a repair. If it is clogged it is best to replace it. Flushing it may clear it for a little while but IMO it will get clogged again soon. You never make it like new again when you flush a clogged core.

 

[ARogg619]

If is clogged make sure you don't listen to someone who says, "flush it out". A flush is for maintenance and not a repair. If it is clogged it is best to replace it. Flushing it may clear it for a little while but IMO it will get clogged again soon. You never make it like new again when you flush a clogged core.

Is there a write up for swapping it out? or is it pretty self explanatory? I know on my Camaro I have to remove the dash to get to the heater core, im hoping that's not the case on this big girl.

 

[OR VietVet]

My 02 is likely the same and if I could not figure it out or wanted it fresh in my head as I took apart, there is always you tube out there. You can be watching the video and stop it when you check it, till you get to the next step. I always look at 2-3 videos in case someone on there is smart enough to "work smart and not hard".

 

[Scottydoggs]

Yeah, the fan blows fine, just not hot. ill let the truck cool down and check my levels. I know I don't have a leak bc I have a brand new driveway with zero spots on it ( for now lol )

i had this same issue on a silerado work truck, the plastic connection leaks so slow you dont see the leak, coolant level drops over a long time, some how the res tank stays at a normal level. then one day the truck starts dinging at you and its over heating. before i found it low on coolant and over heating on me you would have to rev the engine to get any heat if not driving it.

checking to see if both heater hoses are hot is a good check as well like mentioned above.

 

[wjburken]

I always look at 2-3 videos in case someone on there is smart enough to "work smart and not hard".

Truth! Need to make sure you’re not following along with some guy with a “hold my beer and watch this” approach.

Saw a video that had a guy showing how to replace a fuel pump and he said, “A lot of folks will tell you that you should use non-sparking tools to loosen this fuel pump retaining ring, but that’s not necessary” as he takes a steel punch and a steel hammer and begins to go to town. I was waiting for a spark and a fire ball.

 

[OR VietVet]

That's what brass punches and brass hammers are for. I thought you were going to tell me he had a cig in his mouth the whole time.

 

[Fless]

Is it possible that the valve controlling the flow of hot water to the front heater core is not functioning? With dual heat zones, I am assuming (maybe incorrectly) that there are two separate hot water control valves, one for each heater core. Folks with more knowledge than me in this area will chime in.

I'm pretty sure that these don't have a heater control valve in the cooling system. Unless I'm blind, I don't see one on mine.

 

[wjburken]

That's what brass punches and brass hammers are for. I thought you were going to tell me he had a cig in his mouth the whole time.

No kidding! No cigarettes, that I saw anyways!

 

[OR VietVet]

Truth! Need to make sure you’re not following along with some guy with a “hold my beer and watch this” approach.

Saw a video that had a guy showing how to replace a fuel pump and he said, “A lot of folks will tell you that you should use non-sparking tools to loosen this fuel pump retaining ring, but that’s not necessary” as he takes a steel punch and a steel hammer and begins to go to town. I was waiting for a spark and a fire ball.

No kidding! No cigarettes, that I saw anyways!

Yea, usually when you run in to the video of "here, hold my beer while I do......" there is a cig involved as well. Never smoked ever in my life so it was never a problem for me. LOL

 

[Doubeleive]

Good Morning All,

So I have this 2000 Yukon I bought as my winter ride / work beast. As its getting pretty cold now, ive been using the heat and lately the heat from the dash is just WEAK. it takes forever to get warm if it even decides to. Now, my rear heat is perfect and warms up just as you would expect. Where should I start with diagnosing this because I want to figure this out asap before its really cold? This is frustrating bc I bought it for winter and to give my Camaro a break but I wound up taking the cover off the Camaro this morning and taking it to work after giving up on the defrost trying to clear the windshield for over 15 minutes. The truck gets up to temp just fine and no overheat issues or anything like that.

Appreciate any help,

Adam

i'm sitting here wondering why no one has suggested checking the front blend door actuator? if the rear works fine that means the system is working properly, that leaves only 2 likely scenario's 1. the front blend door is not working properly. 2. possible front heater core clogged but it is much less likely.
it wont cost you any money to take off the passenger side bottom kick panel and check the hot/cold blend door for proper operation, you can even take off the actuator and turn the door by hand and feel for hot/cold air to verify

 

[OR VietVet]

i'm sitting here wondering why no one has suggested checking the front blend door actuator? if the rear works fine that means the system is working properly, that leaves only 2 likely scenario's 1. the front blend door is not working properly. 2. possible front heater core clogged but it is much less likely.
it wont cost you any money to take off the passenger side bottom kick panel and check the hot/cold blend door for proper operation, you can even take off the actuator and turn the door by hand and feel for hot/cold air to verify

I can explain. "BRAIN FART". We talk about that all the time but wouldn't that involve a blower feel problem.

 

[Doubeleive]

I can explain. "BRAIN FART". We talk about that all the time but wouldn't that involve a blower feel problem.

no, because the blend door only mixes hot & cold it does not control air flow, it could be getting stuck at 20% hot and 80% cold
it works like a Y both hot & cold air flow at up to 100% regardless if it is on 100% hot or 100% cold or anywhere in between
the door moves up and down mixing the air temperature

 

[ARogg619]

I can explain. "BRAIN FART". We talk about that all the time but wouldn't that involve a blower feel problem.

Yeah I mean I get good airflow through the vents, its just not HOT. At least not for a LONG while. I just took the truck to lunch with some of my coworkers. Im gonna let it cool down and check my radiator and overflow levels. Maybe everything just needs to be topped off. I mean, nothing is ever that simple, but maybe

 

[ARogg619]

no, because the blend door only mixes hot & cold it does not control air flow, it could be getting stuck at 20% hot and 80% cold

unrelated im sure, but this truck doesn't have working air conditioning either as far as I know. I only tried to use it like twice since ive owned it and it never got cold. The heat was good when I got the truck a few months ago but its slowly getting worse