Atomis 4 Water Pump Greaser fitting
FYI all you A4 lovers, I was going to screw in the grease cap to lubricate the water pump when I thought I better check to see if there was grease in the cap.
When I unscrewed the cap, the whole fitting came out of the pump. No problem, however upon closer instection I discovered that when the cap was screwed in to push grease into the pump, no grease was coming out the "nipple" end.
It took several hours of soaking in varsol and careful cleaning with a stiff piece of wire to free up the small spring and ball check valve inside the fitting.
It was plugged solid with old grease so any time I tried to lubricate the pump none was going in. After freeing up the ball check valve there is lots of grease coming out of the "nipple" end so I know I am getting grease where it is required.
It would be worth checking as part of your annual maintenance.