I'm writing in response to your skepticism about the engineoil/vacuum cleaner trick in last week's puzzler.
I've been a heavy-equipment mechanic for 30 years and have usedthis technique successfully at least 100 times to change suctionhoses on hydraulic tanks as large as 500 gallons. The seal atthe tank opening doesn't have to be perfect. It's actuallyhelpful to be able to adjust the strength of the vacuum to alower level to keep the vacuum from ingesting oil. I've thoughtabout the risk of explosion, but either I'm really lucky or therisk isn't that high with oil. My worst experience so far waswhen a coworker shut the noisy vacuum cleaner off to tell me itwas "break time." I ended up wearing about 20 gallons ofhydraulic oil.
I really enjoy your show and have introduced several othermechanics to Car Talk.John Carrig