Heater Problem

[roger steele]

I am having a problem with the heater on my 65. When you first pull the control and turn on the fan it blows hot, then gradually gets cool. Is there a blockage? The thermostst is new and the radiator (while not new) seems to be flowing ok. Any help would be appreciated.
Thanks

[Don H.]

Re: Heater Problem

Assuming the engine temp is normal, the heater core could be blocked. Fairly easy to check, drain coolant and disconnect the heater hoses. Flush with a garden hose (not easy to do now in Iowa). Don H.

[Rob M.]

Re: Heater Problem

Don,

Why is this specificly not easy to do in Iowa ?

greetings,
Rob Musquetier
The Netherlands

[Gary S.]

Re: Heater Problem

Probably because their temperatures aren't aboving freezing. ;>

Gary

[Mike M.]

Re: Heater Problem

is your 65 a C-60 equipped vette? if so, the brass heater shut off valve, on top heater bos behind glove box may be dysfunctional. also check the valve placed in line on the heater hose on engine side of firewall. mike

[Jack H.]

Re: Heater Problem

It's also possible that you have road debris (leaves, pine needles, Etc.) inside the heater box that migrates and blocks air flow through the heater core. Without air flowing through the heater box, the core radiates heat and soaks the walls of the duct work. First air flow feeds off the 'distributed' heat then, with a plugged heater core, loses heat and outlet temp drops....

It's not a 'fun' job to pull the Harrison box from the engine compartment, so follow advice of others and check the flow integrity of your heater core first! Also, IF you have to remove inlet/outlet hoses from the heater core, follow instructions in the shop manual--do NOT loosen the hose clamps and PULL on the hoses to free them from the heater core nipples!!!!

Carefully cut the rubber at the heater nipples, peel the rubber hose off the nipple and shorten the hose for re-attachment. It's pretty easy to fatigue fracture the heater core's inlet/outlet pipes at their junction to the core (especially on AC equipped cars) by YANKING fried hoses off the nipple ends!!!!

[Steve Pettit]

Re: Heater Problem

My 66 wouldn't blow hot air (as opposed to its owner my friends say) after I got it out of a twenty year hibernation in the family barn, and it was full of crap just as the above posts suggest. Now we both blow hot air fine.

Regards, Steve Pettit

[roger steele]

Re: Heater Problem

Thanks for the help, now I can make a few checks.