The engine was at normal operating temperature. The "in" line to the heater core is warmer than the "out" line. The out line is cool to the touch. The "in" line is warm, but not as hot as the radiator hose.
After the car was turned off for about 30 min, both lines were very warm. Restarted the car and the heater worked for about 3 or 4 minutes then started blowing cool air. The heater control is set to knee/feet position. The a/c compressor is not running as it would be with a defrost setting.
Removed the hoses and flushed directly, so I'm sure I left air in the core.
The car got back from about a 10 min drive about 15 mins ago. After being parked ( engine off ) for about 10 min the heater hoses are both 140 deg. The lower radiator hose is 170 deg. Just additional info.
Sorry, she didn't try the heat. It was 78 here today. I'm hoping the reverse flush will clear something from the system and get it working again. Won't get to try it til Tuesday, though.
Picked up the flush kit today, but I wanted to be sure. Which line is the inlet for the heater core?
Still haven't resolved this. Took the car to Mazda dealership in Memphis. They determined the aftermarket thermostat was causing a restriction. Replaced the (new) aftermarket thermostat with oem, also replaced the (new) rediator cap with oem cap. Didn't fix the heater problem. They determined the flush adapter installed in the heater hose was causing the problem, replaced the heater hose. Heater worked for about 10 minutes, then back to no heat. On the road at 70 mph in 6th gear ( 2000 rpm ) no heat, in 5th gear (3300 rpm) mild heat, 4th gear (4500 rpm) much more heat. Driving at 1000 to 2000 rpm the engine temp guage will occasionaly climb close to H then move back to normal temp. Also losing some coolant from vent tube at catch tank.
I appologize, I lost track of what I had told you. The water pump was examined while replacing the thermostat, it appeared to be good and was reinstalled. When the thermostat didn't fix the problem, I replaced the water pump. Still no heat.
ok, thanks. It's got me stumped.