92 Cutlass Ciera heater blowing hot AND cold air.

When the heater is set on defrost, the Drivers side blows somewhat warm air (not hot), and the passenger side blows cold air. When set to vent, some vents blow cold and some are warm. Finally on the heater (floor) setting, same thing, drivers is warm, passenger is cold air. What could cause this? I am going to check the coolant level and the thermostat but not sure what to check after that. This is something I would really like to figure out without taking it in being that it is xmas time.

Any help would be GREATLY appreciated.

Inspect the duct work under the dash. After the fan blows the air in, it will pass through the heater core elements and then simply out through what ever vent you have activated. Maybe you have a hose unplugged.

Will check that out Ian. So that I have something else to fall back on, if that isnt it, what would you suggest to try next?

Thx for the info!

Will check that out Ian. So that I have something else to fall back on, if that isnt it, what would you suggest to try next?

Thx for the info!
Assuming you know how to check the thermostat. I apologize, but I read your post wrong... its not air flow your having a problem with... its the temp. Im sorry... (laughing) you should definately check that thermostat. If you check out there ok, inspect the heater core unit itself.. it could be blocked. Have you ever used a radiator stop leak product? If you need tips on checking the thermo, just ask...

P.S What engine do you have... and what is the milage??

Assuming you know how to check the thermostat. I apologize, but I read your post wrong... its not air flow your having a problem with... its the temp. Im sorry... (laughing) you should definately check that thermostat. If you check out there ok, inspect the heater core unit itself.. it could be blocked. Have you ever used a radiator stop leak product? If you need tips on checking the thermo, just ask...

P.S What engine do you have... and what is the milage??

Thats what confuses me, why would half the car blow warm air and the other half cold air if it is the thermostat? It seems if it was that, all the vents would blow warm or cold, not a split between them. I will check the thermo first thing. Not sure on the engine, but the milage is arournd 100k. Thanks for the info Ian, keep it coming!

Thats what confuses me, why would half the car blow warm air and the other half cold air if it is the thermostat? It seems if it was that, all the vents would blow warm or cold, not a split between them. I will check the thermo first thing. Not sure on the engine, but the milage is arournd 100k. Thanks for the info Ian, keep it coming!

It could be a combination of both problems... both things are worth checking.. definately. If your only getting "warm" air, then you definately check the thermostat and the heater core for possible blockage

It could be a combination of both problems... both things are worth checking.. definately. If your only getting "warm" air, then you definately check the thermostat and the heater core for possible blockage

Yea, it is only warm air, so I will definetly check both. Thanks for the info! If I get this fixed, my daughter will greatly appreciate not having to help pay for a mechanic to do it! :lol:

yeah thats the best eh? I think thats what got me into this trade, a combination of liking to work on cars and being cheap... well, maybe not cheap, but just in no mood to pay way to much money.
really, a thermostat is like 15 bucks or something... but once they do it for you... forgetaboutit...