snap on compressor cylinder head leak
my 5 hp 30 gallon snap on compressor sounds like it has a head gasket leak it is pushing air back through the air filter. it actually melted the housing for the air filter
Yes, if air is flowing back out of the intake air filter, then it is likely you need a valve replacement and, it were me, a gasket replacement too.
That the compressed air temperature is melting the filter housing suggests that it's running far too long at one time, and you may be damaging other compressor parts too, as all need a cool down period. See the page on duty cycle for more info on that.
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