car windscreen washer pump?
although dirt cheep don't expect much out of these. they will die after a minute of continuous use.
If you buy them "dirt cheap", perhaps you have your explanation
A windscreen washer pump was my first thought as well, as I have had two of them going for years (15..20 years actually), with much more than a minute at each run.
One bought from new (one of the better brands), the other ripped out of a Fiat going to the slaughter house.
Just don't feed them a higher voltage than designed for and if possible, go lower, as they are a bit noisy at rated voltage.