A small thermos bottle of water- - - -boiling at the time it was filled- - - -should stay hot enough to make a temp gauge move for several hours. That might be more acceptable to a seller than going after his temp bulb with a lighter. A bicyclist's tire pump with the proper adapters can test an oil pressure gauge, or a small battery powered air pump would work as well. Some of them are small and light enough to fit into a backpack.

www.ebay.com/itm/198244930726?

Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!