i have a 98' monte carlo ls with no heat. the thermostat seems fine, theupper radiator house feels pressurized when up to temp so i know it's closingand theengine temperature looks ok (~190?) according to the gauge. i feel nothing inside but cold air. when i toggle heat-cool driver\passengercontrols it sounds like the flapper is moving although i should mention that the heater mode switch doesn't seem to switch properly to front dash vents, windshield and floor works fine. when i let the car heat up and grab the heater corehoses, the return doesn't even seem warm. this may be a stupid question but is the heater core clogged?? any comments would begreatly appreciated. thx!

 

This is a great question for Chris (scc24540). He has had to repair his heater at least once on his 97 Monte. If I remember correctly, he had a similar problem.
Maybe fire off a PM to him if you don't get an answer by the end of the day.

 

thanks a lot for the tip- i did actually read his post about his 95' and was wondering if he was able to flush the core out without replacing! i'm gonna give that a shot

 

should the heater core have flow all the time or is there a control valve that blocks flow to the core when not calling for heat?

 

i actually got a couple drawing depicting the entire heater\AC unit blend valves etc. dual\single zones. i tried toupload here but apparently 250k jpeg is too large lol... anywayz flushing the heater core worked perfectly! i bought 2ft of 5\8" od poly flow tubing and shoved that into heater core hoses, then flushed carefully both directions using a needle valve in series with the water supply so i didn't over pressurize the core. if anybody has problems and needs these drawings just shoot me a message i would be happy to email them to you...

E