My 1991 Chevy K1500 Blazer (5.7L) has no heat, or at best luke warm. The coolant is full, I have replaced the thermostat, heater core, radiator, engine temp sensor, and the fan clutch. The engine temp stays just above the 100 mark, about 120-125 or so. The blower motor blows on all speeds as it should, but the heat stays luke warm at best. What concerns me is the engine temp does not get any higher than 120-125.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
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Does anyone know what the problem might be?<o></o>
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Thanks.

 

"I have replaced the thermostat, heater core, radiator, engine temp sensor, and the fan clutch."

Recently? To solve this problem?
You may have more than 1 problem. Are you basing your temp readings off the gauge. If so the gauge maybe incorrect and the air door is stuck on cool air instead of hot. You need to get a actual reading temp readings either with a infrared gun or with a scan tool looking at the ECT reading in the data. Feel the heater hoses are they both hot? Do they feel the same temp? If you let it idle for a while then rev it for a few minutes does it get heat?