Vacuum testing from the dipstick

[S50Sinner]

Originally Posted by JFP in PA

If you have no vacuum signal (which should only be 4-5 inches of water at fully warm idle, not Hg), the dipstick housing is open somewhere. You can confirm this by smoke testing the tube, which will show you exactly where it is leaking.

Thanks, that's what I thought but didn't want to dive headlong into a wild goose chase before confirming. I'll dig into the dipstick assembly tomorrow and report back with findings.