Bought this off eBay and it has a wear mark pictured. You can feel a difference in the metal if you run your finger across it, but you can barely feel it. It's not a groove so much as simply a wear mark.

Will it cause problems with the rear main seal?


Another odd thing it was painted for whatever reason. Will that small notch be enough to affect balance?



General question, to confirm that it's a S5 counterweight I measure between where my fingers are...not the beveled/angled portion

 

the wear mark usually isn't a problem, but you can slightly put the rear main seal in a different spot

 

The wear is common and won't cause any issues. Any used counterweight will have a line there. Just use a new rear main seal and you won't have any problem.

The other mark is from a hammer when someone was trying to shock it loose from the eshaft. The auto counterweights can be a beast to remove sometimes.

It is painted because it came off a mazda reman engine...mazda loves to paint any parts that they reuse in their remans, which would be fine, except they do a shitty job of it with shitty colors, lol.

Yes you measure the area shown to get an idea which year/series it is from.