98 chev blazer heat problems

I have no heat at all. No air come out the floor vent. When selector is turned to the floor position , cold air comes out the defroster. Selector position works for the dash vents and the defroster. I was told the heater
core was bad and mode actuator needs replacing which means tearing out the whole dash. Any help
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I just replaced the thermostat in my 1997 Blazer. I had some heat while driving down the road, and almost none while sitting at a traffic light, or idling. It was a $7 part at NAPA (including the tax) and 20 minutes to put it in (most of that time was spent trying to dig up the right size sockets). I decided that for $7, it was worth a shot before I took it in to have my heater core worked on. Worked like a charm!
That said, I've had to have my heater core unplugged a couple times in this blazer. From what I've been told, Dexcool (the pink stuff) is known for being a pain in the blazers. It can crystalize into a sludge that plugs up heater cores. If that is the case, you might be able to get someone to unplug your heater core without replacing it.
As for the mode actuator, I don't know what that takes to replace. I'm sure someone around here can give you an idea as to the amount of disassembly that is involved with that project.
-NW
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Go to a radiator shop and have them look at it. Ask them to flush out the heater core, it may just be plugged with gunk (perhaps someone added antifreeze to the dex cool).
I had same prob with my 98 a cpl years ago. Dealership wanted $500 (later said they would pay half since we just bought it from them) to replace the heater core. $30 later from a good radiator shop, I had heat & it has worked fine since then.
Dave

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I can certainly understand the clogged heater core causing no heat but why would the floor vent stop working at the same time?
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I recently found the problem with the heat.It was a broken door in the heater assy. The door is vac. activated and one of the pivot post was broken causing the door to jam. The whole dash had to come out to even get to it. $14 part and $600 labor later I finally have heat. I would advise anyone having this problem to put in a new haeter core right away to avoid the aggrivation of having it ripped out again. Hope this helps someone later down the road
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if you locate the two heater hoses going to the heater core and both of them are hot once the truck is warmed up. You can pretty much bet the problem is in the dash. Other than the obvious issue with a leaking core.
Some cars have manual heater doors and others have vacuum operated doors, and you can really have a hell of a time with "electronic" dashes.
some vehicles have a heater control valves that screw up, its in line on the heater hoses and controls the flow of water to the heater core.
Yea I agree, it you are going to pull the dash you might as well put a heater core in then, if your car is more than a couple of years old.

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