Heat on 2000 GMC Sierra

Hello,
I have 2000 GMC Sierra 1/2 ton, 60 000 km and it just turned into winter a week ago or so. I feel that the heat is builing too slow, slower than it used to in previus
winters, (4 of them so far). The temperature gauge is claiming up to about 95 deg, but I feel it takes much longer as it used to do, and not much heat comming out initially. I feed that I had hot air almost instantly before. I changed oil and all the filters yesterday, including the passenger compartment filter, that is the 3rd time I changed the cabin filter, so it is not plugged. The temp gauge does go up to the same level as it always does, so I do not think it is a thermostat problem By the way I was looking yesterday where the thermostat is on this engine, (4.8 l V8), I think it is different that the old vehicles, did not look too long for it, but I think it is on the water pump on the return hose from the rad. Any thoughts on this? Is this a problem or it is just me getting too old?
Ziggie
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You could have a plugged heater core. Did you ever drain and refill the coolant? Is there any chance that the anti-freeze was mixed with the green stuff?
Now to a different problem. The new body style GM pickups & SUV's have a problem with the ouside air/recirculate door. Also the heater box may not be
sealed right just above the door. Have someone drive it at freeway speeds, during cold temperatures, while you reach up behind the glove box feeling for a cold air leak. Report back if you have this problem. Lynn
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Thanks Lynn,
Have this truck since mile 0, 9 km or so, The coolant was not drained ever or mixed with a green stuff. Added some once, that is all. Will check for the cold air leak.
Ziggie

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4 yrs, 60k is more than enough for the dexcool in your system. Drain and flush the system, backflush the heater core, replace the t-stat and radiator cap.
Doc

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