Heater woes...again

[jrhone]

OK...so maybe 10 years ago I rebuilt my heater box.  Got a used heater core, and replaced all the seals.  Heat was working great.  Over the years it has slowly lost temp and now only gives heat when idling for a while, other than that its cool air coming out of the heater.  So it looks like time to rebuild it again.  Should I just get a new heater core, or is there a way to rebuild the heater core?  The last one I took to a radiator shop and they tested it and said it was good.  Is it just a small radiator that the shop can take the tank off and rod out the core?  New radiator cores are about $500.  Used ones are much cheaper, but will I be in the same situation in 10 years?  

[tech71]

I tried 2 local radiator shops for repairing mine, they both said it was too far gone. I think that translates to " easier profit out there" or maybe "no money to be made there"

Bought a new one and was done with it.

40-50 years is a long time in radiator years?

Edited March 14, 2021 by tech71

[SydneyTii]

Are you sure it’s not the valve?

[02Les]

Sounds like a restriction/blockage, like the valve as mentioned above.

[jrhone]

Will check the valve.  Thx guys.  Is there any way to check it without removing it?  Operation of the heat lever is smooth without any resistance. 

Edited March 15, 2021 by jrhone

[John76]

I'm with SydneyTii....sounds like the valve is stuck in the closed position.

Mine stuck open in the middle-warm position. which was OK for winter and fall, but a pain in the spring & summer.

Although my lever moved from closed to open, I found the shaft on the plastic 1/2 ball valve was slipping.

Try JB-Weld as a fix. I worked for me and has lasted ~ 15+ years. 

John

PS: This is assuming your core is not leaking and flows water in both directions...easy to check with a garden hose.

[Mike Self]

It's also possible that the bowden cable that connects the dash lever to the heat valve is either broken or has come loose at one end or the other.  If the outer sheath has come loose, the inner cable (wire) won't move properly, and even if the dash lever points to Hot, the valve won't be fully open--or open at all.  You need to check both ends of the cable while moving the lever--see if the inner cable moves when you move the lever.  The bellcrank on the valve should move in about a 1120 degree arc from fully closed to fully open. 

 

And as was previously pointed out, the later valves have a plastic ball, connected to the plastic piece with a square end into which the bellcrrank is inserted.  If that squared off end wears or gets rounded off, the cable will move properly but the valve ball won't move at all.  Much easier to check that than pulling the heater box!

 

mike

[Mike Self]

It's also possible that the bowden cable that connects the dash lever to the heat valve is either broken or has come loose at one end or the other.  If the outer sheath has come loose, the inner cable (wire) won't move properly, and even if the dash lever points to Hot, the valve won't be fully open--or open at all.  You need to check both ends of the cable while moving the lever--see if the inner cable moves when you move the lever.  The bellcrank on the valve should move in about a 120 degree arc from fully closed to fully open. 

 

And as was previously pointed out, the later valves have a plastic ball, connected to the plastic piece with a square end into which the bellcrank is inserted.  If that squared off end wears or gets rounded off, the cable will move properly but the valve ball won't move at all.  Much easier to check that than pulling the heater box!

 

mike

[jrhone]

Ok.  Update.  Went to the garage. Warmed up the car and manually turned the heater valve to the open position.  Turn the fan on and NO hot air.  Cold.  The hose going into the valve was hot.  The hose on the other side of the valve is lukewarm at best.  So it seems the valve is stuck closed.  Also seems to be leaking just a bit from the valve.  Not dripping just a bead of moisture under the valve and i could feel some wetness from the back of the valve.   So the first step may be to swap the valve and go from there.  

[SydneyTii]

There’s a good article on the rebuild and new insert that someone on here sells, that’s what I used and its great!