1999 Malibu heating problem

[rengland]

I have a 99 malibu which quit putting out hot air from the heater.The blower works fine.We put in new thermostat.Changed coolant with new original fluid.Also blead air with little bleeder on top of water pump.Last night I let car warm to almost 200 with blower on 5.Air from dash was ice cold.Today I warmed car with blower off and when I first turned it on it blew hot air for a minute and then went to cold.Seems like core isn't getting enough flow to me.My son-in-law also noticed that with car at temp bottom radiator hose was still cold to touch.I was a mechanic for years,but that was before all this computor stuff was added so I'm lost on these new ones.Thanks for any help guys.
P.S. car has been kept up well and has 70,000 miles on it.

[Mark E M]

This has nothing to do with the computers... Lower radiator hose cold after warm up is just what it seems. no water flow pull lower hose and see if you can find a blockage. Happened to mine once and I got partial flow by putting pressure at the top of radiator with a pressure tester. Blew some of the gunk out the lower opening...Later I had radiator cleaned and rerodded. now no problem.. hope this helps.. Later Mark.

[desertmike1]

Feel the two hose's between the firewall and engine, if they are very hot to touch this indicates good flow through your heater core. If there is good "flow" your problem is under the dash, possibly an air damper control circuit or drive motor.

This is were I would begin trouble-shooting.

Good Luck

Mike

[sdawson]

I hVE 98 Mlibu the heater ac quit blowing then came back on but it iether comes on then dies down or dont come on att all? any suggestions

[manicmechanix]

Originally Posted by desertmike1

Feel the two hose's between the firewall and engine, if they are very hot to touch this indicates good flow through your heater core. If there is good "flow" your problem is under the dash, possibly an air damper control circuit or drive motor.

This is were I would begin trouble-shooting.

Good Luck

Mike

I agree if the car is running at normal operating tempature (not overheating ), then the cooling system is most likely circulating through the radiator, and the lower radiator hose wouldn't necessarliy be hot if it's cold out becuse it's went through the radiator. Better to feel the upper hose anyway. But to check for circulation through the heater core, you'd feel the heater hoses. My guess is the problem is in the heater air blend mechanism.

I have the same problem on my maluibu that I need to fix.

[Johnny R]

Originally Posted by sdawson

I hVE 98 Mlibu the heater ac quit blowing then came back on but it iether comes on then dies down or dont come on att all? any suggestions

This is a different problem than the original post. I recommend you open a new thread; the replies will be specific to your problem. Also, use the search feature using the key words "air conditioning". The solution may already be there. Best of luck.

[xeroinfinity]

Id also look at post dates before posting in 4 year old threads.