QuestionI have a 4.3 L V6 1995 Astro Van and am currently having heating problems. The blower works but it is mainly lukewarm air - and my temperature guage reads 210 most of the time. Is there a valve that lets the coolant flow from the engine compartment to the heater core that may be bad. I don't appear to have any leaks here - have had the rad. plastic tanks replaced in past. Is the valve electrically or vac-operated? - something easily changed?
I also have the problem with the HVAC vents that shift the air direction under high engine load (vac-related issue) that I have been trying to solve forever. I replaced the main vac line (7/32") from the manifold to the black plastic ball (accum?) but it did not help the problem. Several years ago I had the entire hvac switch module replaced - but it did not improve after that either. Taking apart the lower dash I have found the multi-colored vac lines that attach to the switch module but did not notice anything disconnected or damaged - not sure where the vac supply line comes through the firewall to reach the switch assembly. Any help appreciated.
AnswerHello Randy,
I believe there are some solenoid valves that control vacuum to the different door motors, but to the best of my knowledge, there is no water control valve.
But if there is, it would be in one of the heater hoses, which is where you need to go anyway, to see if they are BOTH getting hot.
If they are, then I would assume(bad word sometimes), that coolant is flowing through the heater core, and air doors is the problem.
But if the hoses are not evenly hot, then you could have an air lock in the core, a stopped up core, or a water valve that we don't know about that is not opening.
Check the heater hoses first, and if they are hot, then working on that everpresent vacuum problem is where you probably need to be.
Could be the core is fine, the vacuum is doing what it should, the coolant is flowing like it should, and the problem is a stuck door.
Good luck,
Van
