threaded 1/2" plug on top of my riser/elbow...what's it for?

[Dui]

I see a plug on the top of my riser? Any idea what its for?

 

[Bondo]

Re: threaded 1/2" plug on top of my riser/elbow...what's it for?

I see a plug on the top of my riser? Any idea what its for?

Ayuh,... Hard to say, without knowin' which risers ya got....

 

[mpdive]

Re: threaded 1/2" plug on top of my riser/elbow...what's it for?

Is that not where the cigarette lighter screws into Bond-o?

 

[Bondo]

Re: threaded 1/2" plug on top of my riser/elbow...what's it for?

Is that not where the cigarette lighter screws into Bond-o?

Ayuh,... Like I said,... It depends on Which risers ya got,....

 

[Bt Doctur]

Re: threaded 1/2" plug on top of my riser/elbow...what's it for?

going by the signature info, emissions testing

 

[achris]

Re: threaded 1/2" plug on top of my riser/elbow...what's it for?

I remember some of the 90s engines had a whole pile of snot on them for use in Lake Bodensee (Switzerland). And the hole at the top of the elbow could be for an O2 sensor.

Just a thought....

 

[Dui]

Re: threaded 1/2" plug on top of my riser/elbow...what's it for?

Thanks Bondo and gang for your replies. The plug is threaded with an allan key receiver. Don't know how to describe the riser except its stock with my engine s/n for an 2008 Tahoe Q6, 5L MPI. Could it be used for inspection of the riser internal condition using camera probe or perhaps access for a wire/screwdriver to poke the drain from above after removing the hose below?

 

[Bondo]

Re: threaded 1/2" plug on top of my riser/elbow...what's it for?

Thanks Bondo and gang for your replies. The plug is threaded with an allan key receiver. Don't know how to describe the riser except its stock with my engine s/n for an 2008 Tahoe Q6, 5L MPI. Could it be used for inspection of the riser internal condition using camera probe or perhaps access for a wire/screwdriver to poke the drain from above after removing the hose below?

Ayuh,.... BD, 'n Chris think they're passages to the Exhaust side, not the cooling jacket,...
I've seen a few of 'em, but haven't pulled 'em apart...

 

[achris]

Re: threaded 1/2" plug on top of my riser/elbow...what's it for?

Thanks Bondo and gang for your replies. The plug is threaded with an allan key receiver. Don't know how to describe the riser except its stock with my engine s/n for an 2008 Tahoe Q6, 5L MPI. Could it be used for inspection of the riser internal condition using camera probe or perhaps access for a wire/screwdriver to poke the drain from above after removing the hose below?

Here a picture of the elbow. Which hole are you referring to, B or K?

 

[Dui]

Re: threaded 1/2" plug on top of my riser/elbow...what's it for?

Wow, that looks like it. Its B. Thank you for your efforts. Goes through the exhaust cavity? Would it line up with the manifold drain? Could it be used to probe the manifold drain?

 

[Don S]

Re: threaded 1/2" plug on top of my riser/elbow...what's it for?

It could be nothing more than a spot the held the core in place during casting in the foundry. The pipe plug just made filling the hole easy.

You have to understand, Mercruiser does not tell people WHY they do what they do.

You might call Mercruiser, they would have a better WHY answer than anyone here.

 

[achris]

Re: threaded 1/2" plug on top of my riser/elbow...what's it for?

Wow, that looks like it. Its B. Thank you for your efforts. Goes through the exhaust cavity?

Yep...

Would it line up with the manifold drain? Could it be used to probe the manifold drain?

Nope...