It's a 1990 Z24 Cavalier, with a 3.1 V-6.

I get no heat in the car whatsoever. The blower motor works fine, and the vent doors operate... I replaced the thermostat twice with no results.
It really does'nt seem to have a heater control valve. Looks like the water gets to the heater core through small metal tubes, but they don't seem to heat up after the engine is warm.....has this happened to anyone? How'd you fix it?
The only thing I can think of, is a clogged tube or heater core. But I've never heard of that happening to anyone before. Any thoughts appreciated.

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-1983 L69 Camaro Z28 305 H.O. (Bored .030 over,Teflon oil seals,Melling H.V. oil pump,Hyperetic pistons,chrome-moly rings,2040 Crane compu-cam) T-tops, 3:73 Open rear, BW T-5, Rebuilt E4ME 4 Barrel, Duel Snorkle Air Cleaner w/K&N Filter , Rhino Clutch, Crane 2040 Compu-cam, LS1 valve springs, porting, PST front end kit. Now for paint, interior, etc...etc.... Also:
2000 S10 4.3L 4WD LS
1995 Ford Thunderchicken, 4.6 V-8

 

I have seen quite a few heater cores plug up, try running a garden hose through it....

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R
and 2 POS commuters...

R.I.P. #3
"He can see air"