Question : Tapped hole sizes in crank pulley?

[REV'd]

1999 Lumina with 3.1

Needing to remove the crank pulley for timing cover gasket replacement. The three threaded holes that you use for the puller, are those indeed metric threads? My threads are rusted and I want to run a tap through them before putting the puller bolts in them. Just wanting to grab the correct tap from work. Didn't want to run an english tap through metric holes. Thanks in advance.

[3400-95-Modified]

Yes they are metric but I don't know the size off the top of my head.


Just grabbed a pic M10x1.5 is the dirty set.

[REV'd]

Thanks, greatly appreciated! I could start a metric bolt from my puller set by hand, but it only went about 4 or 5 threads. From my die making days I know the 3/8 and 10mm can be easily mixed up and actually thread in fully in most cases. With everything else being metric on the engine, I was 98% sure, but wanted that last 2%.

Crappy thing is my back-up vehicle didn't want to run right this morning, so now I am at home with two vehicles to work on, and I can't grab a tap like I was planning on. Such is life...