Drain Petcock

[ChasR]

I have a 1998 chev 5.0 liter engine in my boat located at my son's house. He lost the drain plugs for the engine so I have to buy new ones. I want to replace them with petcocks so they don't have to be taken out but don't know the size or thread. I think their 1/2" pipe thread.
Does anyone know the correct size?
Thanks

 

[bruceb58]

Re: Drain Petcock

I would just replace them with plugs. Rust ends up clogging those petcocks and you end up not getting all the water out.

 

[Maclin]

Re: Drain Petcock

I agree with Bruce, the scale and junk will clog up the smaller petcock passages and fool you into thinking it is done draining. Every time I take my block drain plugs out I poke an allen wrench up in there and always dislodge something and am amazed at how much more water drains out.

 

[Maclin]

Re: Drain Petcock

I wa not much help with the size was I, sorry! I think you have the size correct.

 

[Don S]

Re: Drain Petcock

The block drains are 1/4" NPT, and you really don't want to use petcocks in there instead of plugs.
When you drain the block, the holes on raw water cooled engines tend to clog up with rust, mud and sand.
When you drain the engine, you are supposed to use a wire to probe the hole and make sure it all drains out.
There are a lot of people that miss that step, and end up replacing an engine with a cracked block the next spring.