Originally Posted by rlenz2711
2001 sable with low heat output.
Checked atifreeze (Okay)
Checked heater hose going into firewall ( Both seam hot)
Checked Blend door operation (looks good)
Next step ? Backflush Heater core??
If heater core runs clean could it be the water pump impelers???
Dont really want to pull the water pump for nothing.
is there a way to test the pump without removing???
100,000 miles on car.
Had that same problem with mine (195,000 miles). The head gasket blew at 155,000 so I replace the engine with a 2001 Vulcan - 15,000 miles (Ebay for $150 - I was lucky). Shortly after heat just seemed to die. Finally got fed up with the complaints. Here's what to do. Remove the hose from themostat house to heater core, and the one to the water pump leaving the heater core connected to the hoses. Then clamp the bypass hose and connect an air hose to the that was connected to the water pump. Apply pressure (60 psi) and if you don't blow the core, you will open up the core. Residue from the engine gets caught in the core because it's lower than the bypass. When enough builds up the coolant takes the path of least resistance, and you have no heat. Hope it works for you