I have a 1993 Chevy Silverado, the heater won't plow hot air. It switches like it's suppose to, but no hot air. I've replaced the actuators and flushed the heater core. I have a new radiat

SOURCE: trouble code p0134 and p0171

A code P0134 may mean that one or more of the following has happened:

• Bad O2 (oxygen) sensor
• Bad heater circuit in the O2 sensor
• Wiring or connector to the sensor frayed / broken
• Blown heater circuit fuse
• Holes in the exhaust system
• PCM failure

• Rusted exhaust pipe
• Inspect wiring & connector(s) for problems
• Excessive amperage blowing heater fuse (still requires replacement of sensor but also replacement of blown fuse)
• Replace PCM (only as last resort after all other possibilities are covered.

• The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
• There could be a vacuum leak downstream of the MAF sensor.

• In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
• Inspect all vacuum and PCV hoses, replace if necessary
• Check for a dirty fuel filter and proper fuel pressure

SOURCE: 1999 Chevy Venture continuosly overheating

sounds like u might have a blown head gasket is your oil milky colored

SOURCE: No Heat and Overheating in 1999 Chevy Silverado

After replacing the thermostat, you must bleed the air from the cooling system.

To bleed air from the 2.2L and 2.5L engines, remove the plug or sensor on the top of the thermostat housing. Fill the radiator with coolant until the coolant comes out the hole. Since the plug is made out of steel and the thermostat housing is aluminum, it is a good idea to apply an anti-seizing compound or Teflon® tape on the plug threads prior to installation. Install the plug and continue to fill the radiator. This will vent all trapped air from the engine.

Any trapped air in the heating system will have to be displaced by coolant. Once the cooling system is filled, with the radiator cap off, turn of the heater at it's highest setting. Start the engine and allow it to reach operating temp. You should see a drop in the coolant level as the air in the heating system is displaced by coolant. Add coolant to the proper level and replace the radiator cap.

Keep a close eye on the coolant level for at least the next couple of weeks. The cooling system is a "closed" system. Any significant decrease in coolant level indicates a problem.

If you have any questions, let me know.

Please take the time to rate this solution.

Drive safe and be warm.

clarkco

SOURCE: 2000 Chevy Silverado 1500 The heater does not

Had the same thing happen to my truck, the blen door actuator is under the console on passenger side, but the heater core is going to be clogged if you dont have any heat coming through, but a/c works..