t30 7.5hp compressor - oil seaping out of compressor 3/4" copper tube
oil seaping out of compressor 3/4" copper tube fitting,the tube is the one from cylinder to cylinder,not to the tank.
Dick, along with maybe a too-loose fitting, I suspect what you are seeing is oil carrying over from the first to second cylinders.
Oil carryover is typical, but the volume of oil your post suggests is not. That tells me that the piston seals in the first cylinder may be too worn.
You are seeing the oil wicking from the line fittings, but what you are not seeing is the amount of oil that is carrying on into the second cylinder, and then into your air tank and lines.
Compressor lubricating oil is NOT a lubricant for compressed air using equipment, and that carryover oil will cause equipment problems for you.
A coalescent filter will remove oil from the downstream air lines, yet, if there is a lot of oil, the best bet would be to fix it at the source.