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Slow/Low heat issue

Otto Mattik

board member
Joined
Dec 24, 2015
Location
Upper Midwest more or less
92 240 aw70, Nissen's all metal 3 core radiator

After recently replacing thermostat and flushing Nissen's the heat situation has scarcely improved. Wondering if the heater core is the culprit ?

A) Last summer installed new Gates pump, no leaks, works fine
B) Recent installed "Wahler"(parts store clerk claims) 91c thrmstt, has correct bleed valve but no markings of any kind
C) Old thrmstt was 87c
D) Checked hose temps on each side of temp control valve & both hot
E) Control valve looks corroded a bit
F) Slow warm up, when below 15f :raincloud:
G) Squeezed large rad hoses for trapped air to no effect
G) Yes, coolant is topped off, yes bleed valve is up :roll:

Theories ? * link to show "similar" thrmstt

http://www.oreillyauto.com/site/c/d...ck=Search_C2070_1402355_-1&pt=C2070&ppt=C0331
 
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Unmarked thermostat suspect, and make sure the heater valve is actually functioning. Ie. diverting coolant through the heater core instead of letting it by due to internal failure.
 
*Thought about the thermostat, but it behaved nearly the same as it did with the 87c thermstt.

*Closed heater control valve, it got cold. So next determine if it's opening entirely (cable slipped, etc ?)
 
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Unmarked thermostat suspect, and make sure the heater valve is actually functioning. Ie. diverting coolant through the heater core instead of letting it by due to internal failure.

Thanks, the heater valve will close off all heat, so I guess next determine if it's opening completely. Also a buddy showed me a way of reverse flow flushing the core by using the heater core hoses from the front of firewall. He said he did his, and lots of crud came out of the core.

* I've only had the control valve's stick open, but I guess it could be stuck part way closed too, eh ? Probbly going to replace the control valve, as it's corroded anyhow
 
Curious if you are judging slow warmup by heater output alone or gauge?

The gauge and engine temp are normal, & motor(gauge) warms up faster w/ new thermostt.

Unfortunately the cabin heat is lacking. Leaning towards the control valve and/or partially plugged core at this point (?)as everything else appears normal. Last night it got -15f, dicey

Hopefully I can tear into it this weekend, thanks for concern
 
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