Rodd
Recruit
I just went for another run and the heater is working now. Any thoughts?
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Water pump replacement
- Thread starter Rodd
- Start date
dangerousdave
1994 6.5 Suburban
There may have been some coagulated muck in there that finally got washed out. Happened with my wife's car. she didn't like using the heater.
Matt Bachand
Depends on the 6.5
Missy, you are single handedly putting out some excellent how-to write ups for us here. Thank you very much for taking time out of your day to help countless people. You are a true assett.
Missy Good Wench
Wild Blonde from Cloud Mt
A true ASS you say. Oh I missread that. 
Your more than welcome. :thumbsup:
My morning always starts off here or over at the page depending on whats a shakin.
Sometimes these things can seem overwhelming and just way too complex.
One layer at a time and it gets loads easier.
Been a diggin into these little GM diesels since 82 and before that I was wrenching on the 5.7 Olds diesels keeping a couple of them critters running.
Now those were a challenge on a daily basis.
Cheap though.
Bought a lovely Calais for a few hundred $$$ and mixed and matched enough parts to keep the little diesel going for several years. Got great mileage. 27 Hwy was not out of the question.
Later troops
Missy
Your more than welcome. :thumbsup:
My morning always starts off here or over at the page depending on whats a shakin.
Sometimes these things can seem overwhelming and just way too complex.
One layer at a time and it gets loads easier.
Been a diggin into these little GM diesels since 82 and before that I was wrenching on the 5.7 Olds diesels keeping a couple of them critters running.
Now those were a challenge on a daily basis.
Cheap though.
Bought a lovely Calais for a few hundred $$$ and mixed and matched enough parts to keep the little diesel going for several years. Got great mileage. 27 Hwy was not out of the question.
Later troops
Missy
Missy Good Wench
Wild Blonde from Cloud Mt
Muck in the heater is not impossible or possibly the blend door stuck part way and was allowing too much cold air into the mix.
Had a buddy whose wife would not use the AC.
She had this notion that there was chemicals in the air when it was running and was scared to death of it.
OMG
I tried to explain it to her but all the "SPLAININ" in the world was not gonna persuade her.
OHHH well sit in traffic and sweat then.
Missy
Had a buddy whose wife would not use the AC.
She had this notion that there was chemicals in the air when it was running and was scared to death of it.
OMG
I tried to explain it to her but all the "SPLAININ" in the world was not gonna persuade her.
OHHH well sit in traffic and sweat then.
Missy
Missy Good Wench
Wild Blonde from Cloud Mt
I had to learn soo much of the how to on these GM diesels the hard way by the seat of my pants.
Its just nice to be able to share this knowledge and save others the missery of learning the hard way.
Missy
Its just nice to be able to share this knowledge and save others the missery of learning the hard way.
Missy
Missy Good Wench
Wild Blonde from Cloud Mt
When someone gets "Balsy" enough to dig into a 700R4 I will do a how to on one of those creatures.
The first time on one of them wretches I had to make all the special tools to get into it and then tools to reassemble it.
I hate buying special $$$$$$$$$$$$ tools. With a mill and a Lathe most stuff is such that I can make it.
Pullers, installers, seal protectors, etc.
Auto trannies are always fun.
5 bazzillion parts, springs, and other things that go BOOOOIIIIINNNNGGGGGGGGGGG and land where you can't find it.
Missy
The first time on one of them wretches I had to make all the special tools to get into it and then tools to reassemble it.
I hate buying special $$$$$$$$$$$$ tools. With a mill and a Lathe most stuff is such that I can make it.
Pullers, installers, seal protectors, etc.
Auto trannies are always fun.
5 bazzillion parts, springs, and other things that go BOOOOIIIIINNNNGGGGGGGGGGG and land where you can't find it.
Missy
Rodd
Recruit
Muck in the heater is not impossible or possibly the blend door stuck part way and was allowing too much cold air into the mix.
Had a buddy whose wife would not use the AC.
She had this notion that there was chemicals in the air when it was running and was scared to death of it.
OMG
I tried to explain it to her but all the "SPLAININ" in the world was not gonna persuade her.
OHHH well sit in traffic and sweat then.
Missy
Where is the blend door?
Missy Good Wench
Wild Blonde from Cloud Mt
The Blend door is inside the heater box inside the cab
Rodd
Recruit
How do I access the heater box?
Missy Good Wench
Wild Blonde from Cloud Mt
Lots of nasty hard work.
The coolant must be drained, the AC discharged and the dash assembly unbolted and lifted to allow the HVAC box to come out.
There is also a possibility that the little servo motor that runs the blend door (Mounted on the outside the box) may have been a tad sluggish.
These little motors are a black square device and the blend door motor controls how far the door moves from full COLD to full HOT depending on where the knob is set.
If the sucker is working now, leave it alone until it quits.
Heater work is not fun at all, Believe me.
The little motors can be replaced without major work though.
IIRC there is a procedure to reprogram the thing once the motor has been changed.
Its about getting the motor to go where its supposed to in relation to the control knob position.
Best
Missy
The coolant must be drained, the AC discharged and the dash assembly unbolted and lifted to allow the HVAC box to come out.
There is also a possibility that the little servo motor that runs the blend door (Mounted on the outside the box) may have been a tad sluggish.
These little motors are a black square device and the blend door motor controls how far the door moves from full COLD to full HOT depending on where the knob is set.
If the sucker is working now, leave it alone until it quits.
Heater work is not fun at all, Believe me.
The little motors can be replaced without major work though.
IIRC there is a procedure to reprogram the thing once the motor has been changed.
Its about getting the motor to go where its supposed to in relation to the control knob position.
Best
Missy
buddy
Active Member
If I get warm air at all times out the bottom with no air on, does that mean that motor is not set to close the door when the system is off? Or is that just normal? when I turn on the top vents, defrost or AC that bottom air flow goes away. Thanks
ghitch75
livin' in the sticks
i would look for a pencil,pen,lighter,ect....that has went down the defrost and has the damper jammed before i'd rip the dash apart...
just 2 cents....
just 2 cents....
TurboTahoe
Recruit
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NOW in case your in need of some how to on the water pump R&R and cover R&R here is a complete run down.
......
I will be in my office if there are any questions.
Good luck
Missy
WOW! Robyn, you're such a gem! Thanks for the awesome write-up!
-Rob
Rodd
Recruit
Thanks again Missy.
Missy Good Wench
Wild Blonde from Cloud Mt
You folks are very welcome.
Buddy
With the temp control knob set to cold there should be a slight amount of air flowing from the lower vents (On the hump) Outside air temp.
If the air stays warm all the time then this means that the blend door or motor are not working right.
I would be suspect of the servo motor.
If you run into issues I will consult the GM manual specifically and see what the actual procedure is to swap out the motor..
Its not hard, just has to be done correctly to get it opperating right.
Missy
Buddy
With the temp control knob set to cold there should be a slight amount of air flowing from the lower vents (On the hump) Outside air temp.
If the air stays warm all the time then this means that the blend door or motor are not working right.
I would be suspect of the servo motor.
If you run into issues I will consult the GM manual specifically and see what the actual procedure is to swap out the motor..
Its not hard, just has to be done correctly to get it opperating right.
Missy
buddy
Active Member
Thanks Missy, you are correct when it set to cold but off, there is less and its not as warm. if air is set to hot it comes in nice and toasty with it off.
dangerousdave
1994 6.5 Suburban
When my blend door motor died, it would make an annoying rythmic knock each time it was told to move, then stop. Easy to disconnect, still havent replaced it...yet.
DennisG01
Member
Cut an access hole up through the body and radiator supports. Easy access to the drain cock! I learned this from John Kennedy - he has a short write-up about it on his website under "Tech Tips"..."6.2/6.5". There's a pic, too.
Works great!
Missy Good Wench
Wild Blonde from Cloud Mt
I can remember when the heater was a simple thing with a cable to run the temperature control door (Blend door) and vacuum pods to control where the air went to.
Now they are all electronic controled and very suceptible to failures.
The doors are all controled with little stepper motors.
The door that controls the inside outside (Recirc) air flow is set to run until it stalls then it shuts off.
Once the gears wear out the motor will travel to the end and then sit there and skip the teeth and make a thunk thunk thunk sound until it drives you nuts.
Missy
Now they are all electronic controled and very suceptible to failures.
The doors are all controled with little stepper motors.
The door that controls the inside outside (Recirc) air flow is set to run until it stalls then it shuts off.
Once the gears wear out the motor will travel to the end and then sit there and skip the teeth and make a thunk thunk thunk sound until it drives you nuts.
Missy