heater question

[68c10owner]

My heater blows really good but it doesn`t feel to hot. It`s more warm than anything. What can I do to make it blow hotter air?

[tvblazer78]

Originally Posted by 68c10owner

My heater blows really good but it doesn`t feel to hot. It`s more warm than anything. What can I do to make it blow hotter air?

What thermostat is in it? If it is a 160 that could be part of it. One more thing I would do is flush your coolant.

[68c10owner]

Originally Posted by tvblazer78

What thermostat is in it? If it is a 160 that could be part of it. One more thing I would do is flush your coolant.

I don`t know what thermostat it has but it runs around 190-200* according to the factory gauge. The coolant was just done before i got it but it does have air in the system I think. I hear water flowing through it but the radiator and res. is full.

[schoolfire]

Heater core could be blocked? Its easy enough to check... I would disconnect it and try running water through it and see if its slow. If that isnt slowed I would check the lines running to/from radiator/engine and heater core.

Could also be the heater control valve if it had one.

[68c10owner]

Originally Posted by schoolfire

Heater core could be blocked? Its easy enough to check... I would disconnect it and try running water through it and see if its slow. If that isnt slowed I would check the lines running to/from radiator/engine and heater core.

Could also be the heater control valve if it had one.

I can hear water flowing through the core so I don`t think it`s blocked. I`ll look for a heater control valve. It does have a/c if that matters.

[schoolfire]

The control valve just limits the flow of water to the core. If there isnt a valve on the supply lines to open up I would still check for flow through the core... it just sounds like the core isnt ever getting hot enough to provide you with sweet warmth.

[68c10owner]

So how do I check it then? I have a/c so I can`t just unhook the hose.

[schoolfire]

Since I dont know hows yours is setup I took a picture of my trucks heater setup in hopes it might help. I dont know how much it is different but its pretty basic. I would disconnect your core supply lines at the engine and radiator to avoid hurting the core...


Hope that helps

Forgot to mention that the heater core never ties into the A/C... it just gets water from the engine and radiator.

[tvblazer78]

schoolfire, Thanks for taking the time to help out. good stuff.

[68c10owner]

Originally Posted by tvblazer78

schoolfire, Thanks for taking the time to help out. good stuff.

Yes thanks alot. Mine is a 90 but should be similar so i`ll check it out this afternoon when I get home. I forgot about the heat and a/c being seperate. for some reason I was thinking they were tied together but I remember my old 75 gmc was a a/c truck with the a/c stuff missing and the heater worked great. I`ll check the core for blockage. How hard are they to change? I`ve never done one that have the a/c box too. Are they any different? Thanks again.

[schoolfire]

They arent too terrible to replace... I had never done one before and I recently changed the one in the truck in the picture and it took me ~3 hours. I dont remember if the A/C stuff got in the way but I dont think its a big deal.

[rcbildr]

On the a/c rigs, the heater controls are vacuum operated...might want to check if you have good vacuum. One problem I have with my Burb is the vacuum pump went out (mine is diesel) and the doors in the heater box don't close all the way. Also another easy check is to remove the glove box and check the cable on top of the heater box there. My 84 burb was blowing cold air and the bracket that held the cable in place was broken which prevented the door in the heater box from closing all the way. Hope this helps.

[68c10owner]

Originally Posted by rcbildr

On the a/c rigs, the heater controls are vacuum operated...might want to check if you have good vacuum. One problem I have with my Burb is the vacuum pump went out (mine is diesel) and the doors in the heater box don't close all the way. Also another easy check is to remove the glove box and check the cable on top of the heater box there. My 84 burb was blowing cold air and the bracket that held the cable in place was broken which prevented the door in the heater box from closing all the way. Hope this helps.

Thats a good idea. I also noticed that when I put the lever to vent it feels like the a/c is on so maybe the cables aren`t adjusted correctly? Everything else seems to work ok. I really don`t care about myself but I take my 2 kids to daycare in the mornings and it`s cold sometimes, had ice on the windows this morning. Thanks.

[68c10owner]

Well a little update. i let my wife drive it to work the other day and she said the heater worked just fine. I did find out it has a 180 thermostat but I`m thinkin I`m just not driving it far enough to get the temp up to where it blows hot. I do need to do something about the "flowing" sound still. I think I do need to adjust the cables because the defrost doesn`t blow on the windshield at all.

[tvblazer78]

Thanks for the update...