Need new block drain plugs for 5.0 GL PEFS

[Rupp]

Guys,
I need new block drain plugs for my 5.0 GL PEFS. I purchase 1/4 npt (I think this is what I bought) and they thread in correctly but leak like a sieve. I put one of the worn out originals back in and it doesn't leak. So I'm looking for these again.

 

[Bondo]

Guys,
I need new block drain plugs for my 5.0 GL PEFS. I purchase 1/4 npt (I think this is what I bought) and they thread in correctly but leak like a sieve. I put one of the worn out originals back in and it doesn't leak. So I'm looking for these again.

Ayuh,..... Put a dab of sealant on the threads to stop the leak,.....
I use permatex liquid non-hardening myself,.....

 

[Scott Danforth]

May need to chase the block threads. If using a tap from local hardware store, you need to grind the lead off it as it will hit the cylinder before the threads clean up

Sealant works

New plug may have iffy threads. Look to tool chatter marks

 

[Rupp]

I've chased the threads and they are clean as can be. I tried using the white plumbing tape and that didn't help at all. It's very confusing as I lined up the original and new and they look identical except the original has a smaller hole in the middle of the plug which should matter but it's the only difference.

 

[Bondo]

I've chased the threads and they are clean as can be. I tried using the white plumbing tape and that didn't help at all. It's very confusing as I lined up the original and new and they look identical except the original has a smaller hole in the middle of the plug which should matter but it's the only difference.

Ayuh,...... Donno what yer problem is, but the drain holes in the block, are in fact, 1/4" pipe thread,.....

 

[bajaman123]

are you SURE they are 1/4" pipe thread? I ask because I know Mercruiser is NOT, it is 1/2-13 standard thread...the plugs have a 'flat' on the face and use a rubber washer...

 

[ESGWheel]

Don’t be shy about using a lot of sealants and in combination. Suggest do this: first warp the plug with the sealing thread cord (link), then take two turns on the Teflon tape and then smear the entire thing with a sealant like Megaloc (link). Keep tightening until it feels fully seated and give it another 1/8 turn. It will not leak.

 

[Scott Danforth]

The block is 1/4 npt

Mercruiser uses adapters to use their blue plastic junk fittings

 

[ESGWheel]

Oh, if you are using plastic, don’t. IMO use brass for both the adaptor (if needed) and plug. Link and link

 

[bajaman123]

The block is 1/4 npt

Mercruiser uses adapters to use their blue plastic junk fittings

Yeah, I replaced all mine with stainless steel versions from Hardin Marine.