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93 K1500 No Heat

imahemi

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imahemi Enthusiast

imahemi

Posted
Posted

in my 93 K1500 4wd 305 the heat has been acting up for a little while now :thumbs:

heater hose routing on mine... out rear of intake into heater core then out of heater core to top of pass side rad

the engine was heating up almost to redline (250ish) then would cool down to normal (205-210) but I am barely getting any warmth from any of the vents (floor, dash or defrost)

 

I started to troubleshoot it by replacing existing tstat with a new 195 one.

that didnt help the situation it does stay cooler now heats up to around 215-220 i think then cools down to about the 195-200

next I changed out the rear outlet as it was badly corroded (mainly just for piece of mind)

again nothing changed.

next I changed the heater blend door actuator... seemed like it was working better but still not running me out of the truck.

now its like its back to square one :(

 

I have checked to make sure it is full on coolant and I do NOT hear it "gargling inside" as it had in the past...

my windows dont have that sticky fogging either like the heater core is going out

 

 

next thing I was going to do was to back flush the heater core and hope that works...

 

any other ideas?

 

 

edit: my first post FINALLY!!!! :D

dcheeseman Enthusiast

dcheeseman

Posted
Posted

I would first back-flush the coolant.....sounds like its all gelled up, causing the coolant not to flow through the heater-core. Therefore causing no heat through the vents, let me know how it goes :)

rodram Enthusiast

rodram

Posted
Posted

if you are not getting circulation through the heater core then flushing the heater core may help ... but if the core is corroded and plugged-up inside then you are looking at needing a new heater core.

 

confirm that there is no air lock in the heater core circulation .. ( I have had a heater core that developed air lock when a faulty head gasket was leaking exhaust gas into the coolant system ... )

 

check the temperature of the two heater core hoses with the engine warmed up and the heater controls fully on ... if the one hose is warm to the touch and the other is not, then the circulation restriction is the heater core..

 

.. if neither of the two hoses to the heater core are warm, then you have a restriction somewhere in the engine .. could be the fitting at the engine side connection going to the heater core, ...

 

.. if both hoses are warm to the touch, then the problem is in your heater blend vent controls ...

imahemi Enthusiast

imahemi

Posted
  • Author
Posted

after i changed the actuator I checked the hoses the rear feeding hose was hot and the return to rad line was warm but not as hot as rear hose... it seams like its working but its not... lol

 

if you are not getting circulation through the heater core then flushing the heater core may help ... but if the core is corroded and plugged-up inside then you are looking at needing a new heater core.

 

check the temperature of the two heater core hoses with the engine warmed up and the heater controls fully on ... if the one hose is warm to the touch and the other is not, then the circulation restriction is the heater core..

 

.. if neither of the two hoses to the heater core are warm, then you have a restriction somewhere in the engine .. could be the fitting at the engine side connection going to the heater core, ...

 

.. if both hoses are warm to the touch, then the problem is in your heater blend vent controls ...

rodram Enthusiast

rodram

Posted
Posted

one hose hot and the other just a little warm ... then it sounds like you have partial flow through the heater core... if it is gummed up that bad and you give it a good flush.... then it may begin to leak ... so IMO it sounds like you may need a new heater core.

imahemi Enthusiast

imahemi

Posted
  • Author
Posted
one hose hot and the other just a little warm ... then it sounds like you have partial flow through the heater core... if it is gummed up that bad and you give it a good flush.... then it may begin to leak ... so IMO it sounds like you may need a new heater core.

 

you recall seeing a replacement thread or good pics of doing it...searched a while back with out the best luck. not looking forward to doing a core INSIDE a vehicle the ones outside are much easier... :)

imahemi Enthusiast

imahemi

Posted
  • Author
Posted

decided to just change the heater core in the truck instead of flushing it... hope it solves the heat issue and i have good heat :shakehead:

imahemi Enthusiast

imahemi

Posted
  • Author
Posted
how much did it cost you? im tired of cold drives to work! lol.

 

Cost me 32 and about a hour total work time for me to put it in... Just tested it out and I think that did it

radiator Enthusiast

radiator

Posted
Posted

Yeah heater cores in tose trucks are a piece of cake. just take off the plastic cover under the dash disconnect the hoses and it should pop right out.

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