poor heat

TorrentUser

I have a 2007 Pontiac Torrent. A few weeks ago it was -35 C and I all of a sudden had no heat. The vents were only blowing cold air. I took it to dealership and they blamed it on the motor. They said a manifold gasket leak was the most likely cause. They also found :sludge" in the oil and in the coolant. I got a used motor and transmission 80,000 kms on it. Swapped the motor, and transmission, bought a new radiator, and flushed the heater core. I have some heat but it doesnt seem to want to kick in unless the RPM's are upwards of 2500. I am at a loss at this point what I need to do to get some actual heat in car. HELP!

thecardoc3

Did you try bleeding the air from the heater core and hoses? Some of the time flushing a heater core can make a difference, but they usually need to be replaced if restricted. With the engine at full operating temperature and the system set to full heat and high blower is one of the heater hoses hotter than the other? They should both be very hot to the touch, and you won't want to hold your hand on them. If one of the hoses is colder then you have a restriction to the coolant flow either from clogging or an air pocket. If both hoses are very hot. then you need to check to see if the temperature blend door is moving to command full heat.