s-10 heater doest work

[dvsguyca12]

My heater has been out for a while a mechanic told me it is possible because i changed my thermastat to a lower tempature one is that true... Or is it more likly to be a clog in the heater core?

[OverBoardProject]

Welcome to Automotive Forums

T-stat is possible, but I'd think that the plugged heater core is more likely.

Using a prestone flush kit and see what happens. We're really suposed to flush the system every second year anyways

[CELDesign]

Most likely it is your thermostat, on my '99 4.3 liter when the thermostat went bad the heat did not work...when I replaced it the heat worked again. On the S-10's with the 4.3 the thermostat is backwards, they stay cool and don't produce heat.

[hondaboy16v]

a lower temp thermostat is not the greatest idea with the 4.3, this motor tends to be very particular when it comes to operating temperature. However, changing back to a 195 thermostat would be much easier, so try that first. To be honest though, it probably won't help. Overboardproject is right, do the system flush. Your best bet (after flushing the entire system) would be to disconnect both heater hoses and buy a fitting from auto zone or the like that wil allow you to attach a water hose to the OUTLET hose running from the heater core. Then attach the hose to a faucet and crank hot water through the heater core until the water runs clear. Running the water through in a reverse direction will help break up deposites that may be keeping the core from working properly. We did this to my 95 and that core puked sludge for a minute solid. Been working fine ever since.