nesluopetan

I have a 06 V and last winter my heater worked well but this year I have zero heat, regardless how long I drive the car. It's ice cold. Blower motor and electronics all come on fine, everything acts like it's working just no heat at all

I originally thought it was a clogged heater core so I took the car to 2 shops for opinions to back me up. First shop told me it needs a heater core and the quote to replace it and recharge the AC was mid 700s. They said it's a total buggar and the dash has to come out, etc.

I still decided to take it to a different shop for a 2nd opinion and this is where I am majorly confused. This is what they said,copied straight from their work order/estimate:

CLIENT STATES: THERE IS NO HEAT IN THE CAR. WONDERS IF THE HEATER CORE IS PLUGGED. INSPECT & ADVISE.

Tech Notes:

Got the engine up to operating temp & confirmed the vents were cold when setting was on hot & then checked the temp at both heater hoses. The inlet was 156 F & the outlet was 154 F. Those temps indicate the heater core is not plugged internally. The fact that they are so close would indicate that there is no air flow across the heater core. I pulled panels underneath the dash so I could watch the mode & temp doors operate & could see them all move & could hear the change in the air flow. Also the air flow seemed sufficient & then I switched to recirc & that seemed to work also. I tried to remove the blower motor to get a look inside the HVAC module but I already had twice the time allowed in it. If I can get more time I will try looking in from the cabin air filter side. Pulled the cabin air filter to inspect. No problem found.

So now I am back to square one. Is it a heater core or is it not? Since this job is so expensive I don't want to **** in the wind and just throw money at a heater core if that's not the issue. The only other thing I can think of is the fact I had a maggie blower installed on my car in the summer. The blower was for a LS6 but I purchased the right TB adapter and valley cover, injector adapters, etc to make it work on my LS2.

I asked the shop who installed the blower if adding the blower will affect the heat/cooling system at all and they said it wouldn't. I trust this shop completely, but I just want to verify they didn't accidentally miss a step with adapting the blower to my ls2 that could potentially cause my heater not to work. I'm not sure if my heat stopped working after the blower install or before since the blower was installed in the summer. Does a supercharger install have anything to do with the coolant lines or heater core? Excuse my ignorance here, I'm a old school sbc and bbc guy where the heater core lines come from the water pump or intake manifold, I'm not as familiar with LS motors and how the heating system works.

Any advice or recommendations you can offer to help me narrow this problem down will be greatly appreciated. If we missed something when adapting the LS6 to LS2 blower that would cause the heat issue i'd like to know so I can look at that route and figure out how to fix it. If it's a bad heater core I don't mind spending the cash to have it replaced. I just want to put my money in the right place, I am sure you all understand.

Thank you.

TeamSorad

iTrader: (2)

is the heat registering on the dashgauge?

Zexell

iTrader: (1)

My initial thought would also have been a mode door. But if the tech checked it and said they were all good...?

05CTSV

iTrader: (16)

The heater lines come out of the water pump on the passengers side of the motor. Not sure that installing super charger would mess with that.

1. Check the coolant level.

2. Does it have the original thermostat? I'd start with checking the thermostat. It could be stuck shut. If that's the case you won't have heat.

madmike9396

iTrader: (29)

if the thermostat were stuck shut the car would over heat

serik21

Not necessarily. If its cold outside and its stuck shut it will take a good long trip before it starts to over heat. Ls motors are pretty efficient at keeping cool

05CTSV

iTrader: (16)

Could also be stuck open and always circulating coolant. You would probably still feel some mildly warm air if that were the case. Either way for a 5-15 dollar part I'd start there then start looking at the more expensive and involved possibilities if that didn't work.

ryridesmotox

I'd start with a thermostat too... If they measured the heat and its only 156°F +/- at the heater core, I can imagine that the thermostat is actually stuck open. It won't allow the coolant to pass through slow enough to bleed off any heat. Spending $700+/- to replace a heater core only to find out its the $15 tstat would suck. Spending $15 and finding out its a heater core would t be that big of a deal

nesluopetan

Thanks guys. I will gladly run and swap out a thermostat just to narrow it down. The electronics on the panel all seems to be working okay, I don't see any issues with the instruments and the tech yesterday verified all the mechanics seem to be working like they should be. I can adjust the temps up to 90 degrees, turn it on high, low, recirc, adjust fans, etc and it still blows ice cold air, even after a 45 minute drive. ZERO heat whatsoever coming out of the vents. I drove around last night and the engine temp went up to 150-160 and stayed there the entire time.

jsteele90

iTrader: (13)

if your engine temp is only 150 degrees after driving for 45 minutes it sounds like your t-stat is stuck open.

kjr6306

iTrader: (1)

Did you or your tuner happen to install a 160 degree Tstat? That may explain the 156 degree temp at the heater core. I doubt your heater core is bad.....what does your antifreeze look like? Did you happen to mix the wrong coolants together? That would plug your core.... To check if your core is plugged just disconnect the inlet and outlet hoses and hook up a garden hose to either side and see how it flows. My guess is that you have a problem with the blend door. Also, the Maggie install would not do anything to your heater...

MN_V

iTrader: (5)

hey guys I start getting some warm air when my coolant is in the 120s to 130s easily. Your coolant should however settle around 190 when driving around with an original thermostat. Either way if the heater core has 155 degree coolant in it the air should not be blowing ice cold. Made me think mod door also was not working right but he checked that. I'm stumped but curious.

silver1r

iTrader: (1)

I have always had good results backflushing the heater core. Just pull the two hose from the water pump that go to the heater core and use a garden hose to back flush it. Its easy and free. Worth a shot

madmike9396

iTrader: (29)

I agree with this

DMM

I'd look at the Thermostat as well. There are some pretty bad 160* aftermarket stats out there, and if they malfunction they can bypass the coolant intended for the heater core. Happened on mine. I would also have coolant temps in the 130's as well.

nesluopetan

This is my thought as well. I did a LS swap in my 63 chevy truck with a 160 thermostat and the heater never blew hot, only warm when the temp was up to the 160 range but it was still manageable and made the cab comfy. So, if my heater was blowing warm air I would think it's because of the thermostat but since it's blowing ice cold air it makes me wonder. My other thought is the fact the heater core lines are both ~150 degrees so there is heat going into it so why there is no heat from the vents is the golden question at this point.

I am going to change the thermostat just for kicks. I have never changed it and the shop didn't change it either. I am not sure what thermostat is installed, if it's a 160 or a 200 or if there is even a thermostat problem. It's still worth replacing so I'll get it done this weekend while I flush the lines.

The coolant looks good. I don't think there is any mixed fluids in there. It doesn't look gummy or oddly colored at all.

I have been thinking about this all day and I am trying to look at the big picture. With these V's, what's all involved with getting the heater to work? We have the coolant lines to the heater core, we have the vents and flap to open to allow the heat from the core to circulate throughout the car from the blower and then we have the controls on the dash to engage the heater, vents and set the temp.

This made me wonder, Could it be a sensor or issue with the actual climate control? For instance, I set it to 90 degrees but what if the computer or climate system isn't getting the signal to go to 90 degrees? is this a possibly at all that there is some type of electrical disconnect between the controls and the AC/Heat system? What if I have it set at 90 but the computer thinks it's set to 60? I'm just trying to think of what else can be going on here.

If both hoses were not 150 degrees from the heater core I would absolutely think it was a core problem. I just can't grasp how I can have 150 degrees going to the core and not have a single ounce of heat coming from the vents.

"I have always had good results backflushing the heater core. Just pull the two hose from the water pump that go to the heater core and use a garden hose to back flush it. Its easy and free. Worth a shot "

so if I read this right I just pull off both hoses at the thermostat that go to the heater core and just stick a hose on one end and turn it on and see what comes out the other end? Doesn't seem too hard to do, especially while i'm already in there and the fluid is drained from the thermostat replacement.

Thank you for all the recommendations and replies. If this were a cheap every day car or easily accessible heater core I would have already swapped it by now. With this car and how big of a pain in the butt it is to change I don't want to assume.. I'd rather narrow it down to a educated guess based on what most of you agree on. I don't mind paying the money to replace the core if that's what it comes down too.. I just hate replacing parts that do not need to be replaced. I've done it too many times over the years which is why I have taken a step back and asked for some advice before I move forward.

You all rock.


nathan

jsteele90

iTrader: (13)

good luck man. having a car with no heat sucks.

nesluopetan

Thank you.. Especially here in Utah. The roads are nice and clear but it's freaking cold out there. I don't mind driving my d-max daily because it does get good mileage but it's just not as fun as the caddy. Being cold sucks but what's worse is how all the windows fog up and I can't defrost them which makes it hard to see out the windows.

I have one of those little cigarette 12v defrosters in the car right now just to keep it manageable but I hurry and move it when I park because of how embarrassing it is to use one. I don't want someone to see that I am using a harbor freight 12v defroster/heater in my caddy..

MN_V

iTrader: (5)

You brought some of the points I was thinking. As far as the auto-temp sensor of the HVAC unit, you can over ride that by switching to manual mode and turning the temp up and fan on to a desired level. If it was out of whack and thought the car's interior was 100+ degrees then that could explain why it would only blow cold air in the 'auto' setting.

Second, even good techs make mistakes or misinterpret how some systems work. If the heater core has 155 degree coolant in it and the vent air is cold - the air is not blowing through it. I really think something is wrong with the modulation system in directing the air through to the heater core. If it's clogged somehow I am not sure if the coolant would be warm on both sides like he tested.

Again, make sure you've tested the system out in manual mode to be sure the sensor is not a problem. Also if you set it cool, i.e. 60 degrees, does it settle down and maintain that temp. That should show a working temp sensor.

nofun

The first or second shop said that blower motor works and there is warm water to
the heater core, but not sure throw. They also stated that they believe the vent
doors are working. I would warm up the car, remove the in cabin filter and turn
the heat on. If the core stays cold then you have no flow, but if it's warm and the
warm air is being blowed out the opening for the in cabin filter you vent doors aren't
working?