I have a 94 pickup w a 22E. I have no heat and would like to fix this issue before winter. I have changed the t-stat but it did not help. Can anyone offer any diagnostic tips? I would hate to change the heater core if I don't have to.

BTW, the engine is out currently while I replace it.

 

well there's your problem.

you might need a new heater core, but lets see what everyone else has to say.

 

well if its out then thats just half of it.......... take your garden hose and flush out the core both ways start at the top and let it drain out the bottom then start on the bottom hose and let it drain out the top and do that a few times untill its clean and flowing freely try that and let us know ok and i guess we might have to wait untill that motor is back in to see if that worked lol

 

On my 91 with the 3.0, there is a little valve on the top of the firewall that allows the coolant to flow into the core. Might want to check that out.
Otherwise, I'd take the dash apart and check out the system. Is the fan pushing air through the vents? I found a nice mound of hair and other crud in between the fan and the rest of the ductwork.

 

When I got my truck the heater didn't work good at all, little heat. Considered changing the T stat but it didn't make sence since it was getting to operating temp fairly fast. Unhooked the hose at the firewall and flushed with the garden hose. Gunk came out for a just a bit but it made all the diffence in the world. Now I just need to fix the fan resistors so it will run on all 4 speeds.

 

Ok, I will do the flush, both directions, while the access to the core is easy. If I get crud, I'll assume that a clogged core was my problem. If not, I guess I'll attack the vent system after i finish the engine replacement. Thanks for the tips.

 

1) Check the heater valve on the firewall. Pull the cable off of it, make sure it moves freely, doesn't leak, and isn't clogged.

2) Check the heater core, and all coolant pipes/radiator.

3) Replace the core if you have to. There's a writeup in my sig.