I wouldn't trust a harbor freight pump to do too well myself.....Some of their tools are OK, some suck. I was going to use that same air operated vac pump - actually, I bought one, but took it back after I read about what a pounding it puts your air compressor through.

I bought the same venturi vac pump from Harbor Freight. Yes, their tools are cheap. Some are good for certain applications. The pump worked great although I didn't keep it on too long to save my compressor, but it pulled a good enough vacuum to yield approx. 35 degrees F from the duct here in central Florida. Paul.

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1984 300CD red/blk 290,000 partial resto
1980 240D 4 sp Brn/palomino gone
1997 Mazda Miata STO edition wife's baby
1988 Lincoln Mark VII LSC next resto
1986 Subaru GL wagon daily
1993 Isuzu pickup field beater
2008 Honda Civic EX-L 5sp wife's new car
1978 Honda XL350
1974 Honda XL70 my Calif. ride in HS