Chevrolet Repair: No heat, chevy lumina, 1993 chevy lumina

Question
Hi I have 1993 chevy lumina van. Barely getting any heat inside van. Fluid level OK  and temperture indicator on dash is about half way.When we leave heat off for a while and then turn on, we get a little heat but then cools off. Thanks

Answer
Hi Rick,
The heater core is mostly stopped up with sludge.
Remove the heater hoses and flush it out with a garden hose heald snugly against the heater hose ends, occasionally reversing direction.

There is a remote possibility that the fitting on the engine is almost plugged, but you can check that while the hoses are disconnected.

Van