I've been brainstorming ideas to deal with my HVAC system redirecting air flow when the engine is under load and supplying very little vacuum.

I've checked the underhood vacuum hoses and will next be trying to find time to check the individual vacuum actuators. The hassle is that to test them, I'll have to remove the instrument panel bezel.

So, I've thinking of possible alternative solutions in case I can't find any other issues which brought me to the idea that perhaps I could supplement or substitute the vacuum supplied by the engine with a dedicated vacuum pump.

I learned this is often done on cars with high-performance engines that cannot supply much vacuum along with many larger trucks to be able to supply vacuum to the brake booster.

So, have any of you tried this? Any suggestions or thoughts?

My preferred solution is to find the vacuum leak, but if nothing else it has been fun to play with this possible solution while visiting family for Thanksgiving.

 

Hey Christine,
Did you put a hand vacuum pump on the line going into the HVAC controls to verify there is a vacuum leak....one that has a gauge on it?
I thought I had a leak once, did this and the HVAC held vacuum...thought it was the HVAC vacuum switch itself, but there was none.

Just curious....

 

The only test I've done so far for the HVAC actuators was by trying to pull a vacuum with my Mityvac vacuum pump at the hard plastic hose that comes through the firewall into the engine compartment that supplies vacuum to the HVAC system. It did not hold any vacuum.

Several years ago I did replace the vacuum control solenoid thinking it was bad, but in retrospect, I think it was fine

What I'd like to do is take the dash cover off and do a proper check. I just have not had the time.

I came up with the idea of having a dedicated vacuum pump for the HVAC while making a cross state trip recently. It was a way to pass the time. LOL When I was able to get online I discovered that dedicated vacuum pumps are a thing, they are commonly used for brake boosters on many Ford pickup trucks.