Heater???Blender door?

[BIGski]

I have read a lot of the different threads here about heater problems, I am almost sure it is a blender door problem but not %100 sure.

The front nor the back has heat coming out when I turnt he heater on. My 99 Exp was bought after it overheated. I had the heads reworked and changed the gaskets from the heads up. When I got the truck running again I had to replace the supply line to the heater core, both ends were broke (would not stay fastened). I felt the supply line to the heater and it was HOT !!! The return line from the heater was luke warm, not as hot as the supply line.

Any suggestions?? maybe a flush?

 

[SkyJumper]

If the return line is cooler than that of the supply line, then you may have a leaking or clogged heater core. If the air is on cold and you switch to heat, do you hear the blend door opening? If the blend door is working properly, then you should be able to hear the door opening, kinda like a vacuum seal being released. Sometimes you need to have your ear down under the dash to be able to hear it over the engine.

 

[BIGski]

I will try and listen good to the change skyjumper, I also think I am going to do a good flush of the system..

 

[SkyJumper]

A flush may be in order, but, with coolant and the contaminants involved over time, those contaminates will find low lieing areas of the coolant flow path, and lie and harden, and that is how cloggage and restrictive flow.

 

[BIGski]

so should I spray some water from a hose into the heater hoses and try to see if it unclogs the heater core?

I already know, from a freeze plug on the drivers side( like a block heater adapter) that popped out, that there is a lot of rust and build up in the system. I fished out as much as I could with the plug out.

 

[SkyJumper]

so should I spray some water from a hose into the heater hoses and try to see if it unclogs the heater core?

No I would never use straight water, that is the whole reason for the rust. Water is the worst enemy to a engine besides lack of oil. But if you have a serious case of rust and sediment in the water passages. My concern would be what the water pump looks like down in valley of it. Probably has a crap load of rust cyrstalized at the bottom of it and in the water passages thru out the block. Eventually the crude in the water pump builds up to the point where it starts to hit the impeller and locks the pump up. But, you do what you think is with in your budget.

 

[BIGski]

when I replaced the head gaskets I replaced the water pump as well. THinking that if it overheated it would be best to replace the pump. and the water was going to be just into the heater core to try and unclog the stoppage.

 

[mont91]

You said front "AND" rear. The flow to the rear core has nothing to do with the flow through the front core. However both cores could be clogged. If you back flush the front and get heat then you will probably have to back flush the rear also.

 

[BIGski]

mont91, you have a good point on if I flushed out the front and it worked then I would probably have to do the rear as well. Well, I sprayed water throught the front heater core and throught the pipes to the back heater core. Still no heat from the front or the rear...

After I sprayed the water in the front and got some gunk out, I got the engine to operating temp. Both hoses, supply and outlet, were both even temp but still no heat in the vehicle.

I tried to listen and I did not hear the blend door open. Did not hear a difference when changing from cold to hot temp. IS there a way I can check the blend door without taking the dash off? Like jumping the switch to make sure it opens right?

 

[jrjr]

Not the greatest instruction but it will get you there....
also........ http://www.heatertreater.net/

http://www.youtube.com/watch?v=cCUzOUqW6Ms

 

[BIGski]

Thanks jrjr, I have a video like that.

Anybody know how to test the temp adjust switch? to make sure it is not my switch before I tear into checking the blender door ??

Like I said both lines going in and coming out of the heater core are equal temp Hott !!

 

[jrjr]

If both lines are HOT then there is flow through the heater core. The issue is then that the blend door is directing cold outside air to the cabin rather than the hot air from the heater core. It closes over the core and stops air from flowing through the core and into the cabin.

My blend door was cracked at the bottom where it sits in the actuator. It still worked but it wouldn't have lasted long. When I pulled the dash to do the core I almost missed the cracks so take a really good look at it if you do just the actuator.... if you can see it. Long as you are that far you may be well advised to do the door too.

Actually the right way would be to pull the dash and replace the core, door and actuator all at the same time. You would save a little money on the door when you get a stock one rather than the metal heatertreater one. Elimination of future headaches is a good thing!

 

[BIGski]

So very true, if I take the dash apart I might as well be ready to change the heater core as well. I guess I will deal with the rear heater first and one I get it working I can work on the front heater.