01 blazer heat issue

[airboss20]

I recently replaced my upper and lower intake seals, as well as the valve cover gaskets. Now my heat doesn't seem to be as efficient as it was before the seal replacement. It takes a long time to get hot, even when my coolant temp gauge reads about 180-190F. I double checked all of my hoses under the hood going to the heater core and they have got to be correct due to the different hose diameters. Any ideas?

[MT-2500]

Things to check for.
Auto or manual controls?
Make sure rad is full of coolant.
Make sure temp is up tp 195 degrees.
Make sure heat setting is switching good from cold to hot.
Good engine vacuum to heater controls.
Does all vent switching work good?
Check coolant flow to and threw heater core.

[airboss20]

Thanks for the reply, and I will check everything you suggested. Here is what I do know. The radiator and resivoir are full, and the hoses from the radiator to the waterneck, hoses from water pump through the heater core are all full and hot. just doesn't seem like it is getting as hot as before. The only change to the core is that I had to drain the coolant and pull the hoses to and from. I know the heater core has refilled with coolant, because I could hear the air flow through it when I put everything back together and started the truck. I know my truck has a climate control issue as far as choosing which vents to blow through, and that is because of the vacuum switch on the tranny leaks ATF into the vacuum lines (which I have yet to replace). but the hot/cold dial has always worked (is that vacuum actuated as well?).

[MT-2500]

Originally Posted by airboss20

Thanks for the reply, and I will check everything you suggested. Here is what I do know. The radiator and resivoir are full, and the hoses from the radiator to the waterneck, hoses from water pump through the heater core are all full and hot. just doesn't seem like it is getting as hot as before. The only change to the core is that I had to drain the coolant and pull the hoses to and from. I know the heater core has refilled with coolant, because I could hear the air flow through it when I put everything back together and started the truck. I know my truck has a climate control issue as far as choosing which vents to blow through, and that is because of the vacuum switch on the tranny leaks ATF into the vacuum lines (which I have yet to replace). but the hot/cold dial has always worked (is that vacuum actuated as well?).

The cold/hot is ACTUATER MOTOR IS ELECTRICAL.
But make sure it is moving all of the way from cold to hot.
And fix the vacuum to controls.
In S-10 how to section there is pictures and info on it.
http://www.automotiveforums.com/vbul...lay.php?f=2069


I would flush heater core and check flow and I have had to switch heater hoses to help flush them.
Different sise hose but can be done if you work at it.

[airboss20]

The problem seems to have self resolved. I believe that there must have been a big air pocket in the coolant channels of the block or heater core. I took it out on the highway for some long distance travel, and just like someone flicked a switch, I had hot hot heat.

[MT-2500]

Originally Posted by airboss20

The problem seems to have self resolved. I believe that there must have been a big air pocket in the coolant channels of the block or heater core. I took it out on the highway for some long distance travel, and just like someone flicked a switch, I had hot hot heat.

Thanks for posting back hoe it went.

Recheck the coolant level in the rad to make sure it has not went down.
Good Luck.