OMC 4.3L drain plugs (1989)

[m100psi]

Hi,

I'm trying to get my engine ready for the season, reconnect the hoses and drain plugs removed for the winter. Both the block plugs and one of the two manifold plugs are what I think I've seen referred to on this forum as "valves", wingnut-looking things that allow draining by loosening instead of removing the plugs.

I couldn't get the starboard manifold plug tight enough to prevent it from draining, and ended up ruining the threads in the process. I think it had only not been leaking before because the hole through the bolt had been clogged so it didn't matter that it wasn't screwed in far enough.

Seems like the easiest way to fix this to remove the small extension that allows the use of valves, and install an OEM plug. I just wanted to check if I'm understanding the situation correctly (that "valves" are something people install aftermarket, and removing the small extension lets me use a normal plug) and if the Sierra 18-4263 is the right OEM replacement plug.

Thanks,
Matt

 

[Scott Danforth]

google radiator petcock. or click on the link https://www.summitracing.com/parts/...K-y6YFVB9VmjbQL3cmj2r7GVb9KVzEcxoCcnYQAvD_BwE

the block threads are 1/4 npt. you may need to chase the threads with a tap. if you do, grind the point off the tap as it will hit the cylinder liner.

 

[m100psi]

OK cool, so really I can use any 1/4" npt brass plug?

Thanks,
Matt

 

[Bondo]

OK cool, so really I can use any 1/4" npt brass plug?

Thanks,
Matt

Ayuh,..... Welcome Aboard,..... That's what I use, maybe a buck apiece at a hardware store,.....

 

[m100psi]

OK, thank you.

Matt