my 67 has a heeting problem. If I leave the heater off for a while and turn it on I get about a minute and a half of heat. It then blows cold. Also crusing at high speeds I get a little heat. What could be causing this problem?

My guesses. pluged heater core, open thermostat, my car is jelouse of my girlfriend and wants to get back at me

I would like to add I have no way of checking coolant temp until I install my gages I f we get a dry day up here.

Feel the heater hoses for one being hot and one cold.

An open or missing thermostat or low coolant level is possible too.

I think both get hot but ill check tomorrow

feed or return lines to heater core at water pump or intake might be clogged with rust/gunk. As stated check the heater hoses after checking other things. Do not remove the heater hoses from the heater core if possible. If it's old you could break the connection on the core. Remove the hoses and check flow from the block and pump side. You might also want to hook up a hose fitting to you heater hoses and flush it out to unclogg it also. Worked for me, I found mine to be plugged at the water pump fitting. My heater core went bad about 4 moths after fixing the same problem you have, but it got me through winter!!! I was able to change it in the spring............just lucky.

Joe

I just replaced mine. I did a search and got some good advice. I ordered a new seal kit for the heater box since it was out.

I also purchased a new piece of firewall insulation and installed that as well. While you have it out you might as well do this stuff since it may be the only opportunity you have to do it.

Best thing I did was have a local radiator shop re-core my original heater core. The pipes on the aftermarket replacements don't necessarily line up well with the holes in your firewall and it can make the job a real pain in the a** when re-installing. If you go with a new core, make sure you get it leak tested.

Good luck.