In a message dated 98-08-18 14:14:05 EDT, you write: << My 4000Q compressor was the same as my UrQ (York) piston type. The 5000, if I recall, was not of piston type... Bob >> Although the URQ and 4 Cylinder 4000s are the same type of compressor, A mini York, They are different part numbers, I believe the differences are how the hoses are bolted on the compressor and where they bolt to.. Scott