My VYII Berlina is on its fourth vacuum issue in 13 years. It has had one of the vacuum actuators replaced three times so far. Same part each time or so I'm told. Stripping the dash to gain access I decided to remove and test the vacuum tank. When I removed a strip of adhesive backed foam covering the two black feed lines (one in from the check valve at the rear of the engine intake plenum, the other out to feed the solenoid valve bank) I discovered that at some point someone had wound several turns of insulation tape around the vac. inlet port (larger of the two ports). Tossed away the tape and found the elbow shaped connector very loose when pushed home onto the port. Found a small piece of suitably sized tubing to slide on the port first, then pushed the connector over that. the fit was way tighter but didn't fix my poor vacuum issue.
Tested the tank by submerging in water and pressurising with air, no bubbles, tank appeared OK.
I removed the solenoid bank and using a bench power supply tested each of the solenoids to make sure they operated. All appeared to work as a click can be heard when applying power. I'm yet to strip the foam filter material from the pack as I suspect due to the poor condition of the foam (i.e disintegrating with heat/age etc) minute particles have entered one or more of the solenoid valves causing poor vacuum flow. Will check this and post another note. Other than that, I may yet need to replace vac. actuator 92140681 yet again as just prior to the failure a definite thud was heard when I switched off the engine.
Sorry for the long winded post all.
For those interested a company called "Air International" appears to be the OEM that produces these HVAC units for Holden (as well as many other car makers worldwide). I am attempting to contact them regarding these vacuum related issues. After reading so many posts from drivers with the same/similar problem, I've concluded that with all the HVAC components working sweetly, this unit just barely operates and that's all. There is little or no margin for aging parts, low vacuum due maybe to ports being partially blocked, reduced diameter vac. lines such as the black inlet line to my tank (forgot that earlier, besides the tape I found the black line from the inlet manifold to have been flattened, it was sitting behind the plastic body of the AC itself and had become partially crushed)
Will post more when I've nutted out this latest failure. Not beaten yet and don't intend to let this thing win.
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