77 olds omega heater core

i have a 77 olds omega that does not give heat itis not leaking i need info on how to change the core thanks

[Oldsguy]

It may not be the core. I would look at the heater control valve first. Hot coolant flows out of the engine (in a v8) from the back of the manifold on the passenger side, (in an L6 it is from the water pump), through a heater control valve, into the heater core, out the heater core, into the water pump (v8 and L6 both). At any rate the valve is probably controlled by vacumm from the heater control module on the dash although on some cars it is a cable. If this valve is stuck closed you won't get any hot coolant to the core. It is easier to check/change than the core itself. On my '76 Omega with a chevy L6 engine the core is very hard to change unless you remove the passenger inner fender well or cut a hole out to access a few of the mounting bolts/nuts on the core housing. I know, I had to do it. yes you read right mounting bolts/nuts, they use both. Some of the locations are studs from the firewall, others are holes with threads on the firewall, I think they did this to aid alignment for r/r of the core housing. Anyway, good luck.

Dan