Paccar mx13 fuel filter socket size?

Anyone knows the socket size for fuel filter cap? Thank you!

 

Someone in YouTube showing how to replace fuel filters on your engine will probably also tell you the socket size.

 

Been there, no one tells about socket )

 

You can also measure it with a caliper. On the DD15, several of the filters need 36mm.

 

Can't measure, I am away from truck..

 

1-1/4" 6 point fits both oil filters and the engine fuel filter cap.

 

Thank you sir