02-27-2007, 10:43 PM
Been noticing sluggish/sporadic response from the temp control knob for a couple years. Recently also noticed a hissing noise coming from the heater control solenoid in the left footwell with the temp knob commanding full cold. Finally decided to replace the heater valve as a troubleshooting measure. Way cheap from pelican parts, about $19. Had to remove oil filter for access, so changed the oil too. I elected not to drain the coolant first, stuffed a rag firmly in the oil filter receiver to prevent coolant from contaminating the oil system. Lost about 2 quarts of coolant when the heater valve was removed. Came off easily despite being 12 years old! Accidentally broke the vacuum line (very brittle) while repositioning the power steering reservoir, reqd extra trip to NAPA for some 5/32" vacuum hose. I was able to reuse the rubber coolant hoses on inlet/outlet of heater valve, but needed new hose clamps, the originals had to be (carefully) twisted and cut off. Reconnected everything, then followed the owners manual procedure for bleeding air from the cooling system, which took a good 15 minutes with the engine at idle. Ops checked the temp knob, it responds like new, each click produces a discernible temp change from the vents, hissing noise also gone.

