The heater blows nothing but cold air. I checked the hoses for leaks and found none. However the inlet hose gets hot while the outlet remains cool. Also my temp gauge started to fluctuate and peg out, then return to normal. (happened twice on way home) I figured the thermostat has something to do with the temp spikes but why no hot air?
"88 Silverado heating problems
Oct 29, 2005
11 Replies
your heater core could be plugged up
Thank goodness you are wrong....otherwise it would be a mighty cold drive to work in the morning.
Ian
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Pull you glovebox liner out... just to the left is a white plastic adjustment for the 'heater' cable that controls the heater flap. Make sure the flap it closed tight, even a'little cold air will kill the heat.
HDS
Sounds like the heater core may be plugged or you have a bad heater hose. The temperature spikes are because the coolant isn't bypassing through the core the way it would normally. I'd just replace the heater core and the heater hoses, not a bad job on a P/U.
The thermostat Closes to allow the Water in the Block to HEAT UP,, it ISNOT shutting off the WATER INTAKE.. it is Shurtting off The Water outlet.. This allows the Water pump to put the Warm water into the HEATER CORE . When the Block Water reaches 195 degrees, the thermostate opens Breaflt to all some water to cool the water down a little then it immediately closes again to KEEP the HOT ( 195degree water Flowing thru the Heater core..
If the Thermastate was to open continuously then you would Get Cold HEAT because The Radiator FAN is Keeping the WATER cold in the Radiator !
DI> Wr>
hard to follow this one. the statement about the thermostat controlling the water flow is correct, so I don't see how that's wrong?
Either the heater core gets hot or it does not.....if the thermostat is working then both heater hoses that run to the heater core should be warm to hot and you have heat.
there may be a number of other issues but if the heat is not working you first look to the water supply.
Heater coolant flows even when thermostat is closed as engine warms up.
You stated that there will be no heat until the thermostat opens. If this was true, I'd never get any heat on -30 degree day, as the t-stat probably doesn't open at all on the drive to work and back.
As other's have mentioned, coolant within the engine and heater hoses/core circulate even while the t/stat is closed.
Ian
Yes... I agree
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