What Is This Hole On The Top Rear Of The Block?

[bigc2330]

What hole is the one that is circled red?
I believe the blue circle is an oil galley plug, but I do not know what the other hole is.
It is threaded.
(This is not my actual picture, so mine is not filled with orange RTV.)
I was replacing the lower manifold gasket and noticed this hole filled with grease. No cap or plug.

The block is a 1990.

 

[Lscam580]

It's an oil galley they plug them off so the oil can flow through the engine. That's a spot where the block making company drills the oil galley one of many

 

[bigc2330]

So I need to plug it or fill it with RTV then?

 

[Lscam580]

They use special plugs for them

 

[Gearbanger 101]

Get yourself a set of steel core gaskets while you're at it. Those fibre ones don't last.

 

[bigc2330]

So is the plug part of the freeze plug kit that I can buy, or something to pick up from Home Depot as a pipe plug?

 

[bigc2330]

I have been searching the local auto part stores and didn't have any luck finding an oil galley plug.

 

[Gearbanger 101]

Your local Ford dealer should be able to get you the specific plug. I believe Dorman makes them as well. This plug kit from Jegs is supposed to have all the ones necessary for an engine block.

JEGS Performance Products 58005, JEGS Brass Freeze Plug Kits | JEGS Performance Products

 

[larrym1961]

Get yourself a set of steel core gaskets while you're at it. Those fibre ones don't last.[/QU
This is good advise. I went thru several of those before I went to steel core.

 

[90sickfox]

The threaded hole in the back of the block is for a knock sensor....usually found in 5.0 truck blocks but some did make it into mustangs....no need to plug the hole...it goes toward the area where the flywheel is.

 

[90sickfox]

Knock sensors were never used in mustangs so the factory left the holes empty...no plug.