heater
 

driving along 94 z-28 heater stopped working and fan will not turn on to cool motor, have put in new radiator, belt, opti spark,sending unit , have bled several times,oh the fan works manully but no heat.help.........

have u checked the fuses in both fuse boxes?

heater
 

yes the fan motor on the heater works,but no heat,and the fan for the motor stopped woking would a fuse cause no heat .is there a heater control valve if so where is it and i will recheck the fuses thanks heip.....

Did you just replace all these things, then have the no heat problem?
Or was the heat working for a while and now doesn't work?
Can you feel your heater hoses and radiator hoses getting hot?
When you did the optispark change, you didn't forget the water pump driveshaft coupler did you?

heater
 

no these were changed about 3to4 months ago,has been running just find heat and all all of a sudden this as come on.heater hose is not real hot,how many bleed screws are there and where located.i did 2screws if there is a third let me no where it is ,please have not been driving now because of problem, oh ,iput another thermostat in it again

Catback, I have the exact same problem I'm working on today with my 91. No heat. I tore into the heater core to see if something was blocking it. Nothing.

I did notice what appears to be a solenoid-controlled three-way valve on the heater hoses. My service manual identifies this as the AIR switching valve, but the valve I see is definitely connected to the heater hoses, not a vacuum line.

Any ideas?

no none sorry

was the coolant level low when it quit working? there are three bleed screws. one on the hose by the alternator, one on the thermostat housing and one at the bottom of the throttle body. try flushing the system. have u used two different kinds of antifreeze? if u mix certain kinds it will gel up and clog things up.

heater
 

it seem like it when i added some coolant about a week before, i did not know about ,the bleed screw under the throttle body, is it connected to a hose the book did not say anything about the third screw, i will go out tommorrow and look .exactly where ,you think i got air in it ,thanks,hope to hear from u soon

if u think u have an air lock then when u bleed it begain with the engine cool or at least not hot and fill the radiator with the cap off watch the coolant level and fill if it drops. when it holds full open the bleeder screws one at a time till u get fluid then close. now start the motor with the radiator cap off and watch the fluid level. if it drops fill. when full put the cap on and bleed the screws again closing when fluid comes out. it helps alot if the car is parked on a upgrade with the front of the car pointed up to help the air out of the system. once done take the car for a ride a couple blocks down the street and back and bleed screws again to check for any left over air. let cool and check radiator to see if its full. once done check coolant resovor and fill to correct level.