Snap on cooling system pressure tester - oil?

[16valve]

Hi friends, i have a Snap on SVT-262 pressure tester, I beileve its made by Stant. There's a sticker on the body of the pump that says I need to oil the tool. What oil do I use? This tester is a very nice unit.

Thanks!

 

[techenthusiast]

I have the stant version

I'm not sure if this is how it's supposed to be done because I didn't know it needs to be oiled(mine gets stiff but I thought that's just how mine is)

I shoot penetrating oil in the hole by the hand pump piston and
Then i give it some pumps without being attached to a radiator

 

[Fedwrench]

I've always used a thin oil like thre in one. A couple of drops will do the job just fine.