Oil Routing at Filter/Engine Interface --Mystery Hole

[Bill Michigan]

This is a photo of the engine block (3.8L) where the filter head is attached. A new gasket (same configuration as the previous one) is in place for reference.

Can anyone identify what should be in threaded hole "C"? It's internally connected to the same passageway as "B," so it seems there should be a plug there to prevent co-mingling of incoming (unfiltered) oil from "A" and outgoing (filtered) oil from "B."

(Note: There's a "Balance Valve" in the filter head to allow the filter to be by-passed if it's plugged, so there's no need for an additional Balance Valve in the block.)

Thanks,

Bill

[abowie]

I reckon there's supposed to be a threaded plug in there.

https://www.sngbarratt.com/English/#/UK ... 202413337)

[mgcjag]

Hi Bill.....i have see 3.8/4.2 blocks both with and without the threaded plug.......most important is the houseing and the seperations built into it.....there are quite a few different types....and a few different gaskets.....so worth haveing an extra look at your houseing and gasket to see how i/p o/p will flow .....Steve

[Bill Michigan]

Thank you, Andrew and Steve, for your quick replies, which were invaluable in helping me sort this all out.

Andrew, you're right: a threaded plug with a slotted top--as shown in Steve's engine block photo--is missing. I now hear that it's not uncommon for this plug to be forgotten in engine rebuilds.

It's part # C15867, and apparently applies to both the 3.8 and 4.2 engines. It's listed in the factory Spare Parts Catalog as the first item on page 3. I couldn't locate it in the factory drawing, but did find it in the illustration a supplier's parts book, with the same part number.

Steve, thanks for alerting me to all the various configurations out there. It looks like I'm OK in that regard. Below is photo of the mating surfaces on the block, the gasket and the filter head. Also included is a shot of a yellow strip passed from the should-be-plugged hole to the filtered oil passageway.

The proper plug is on order and expected to be here in a few days. Since I'm now reluctant to drive the car without it, can anyone provide the thread specs so I can fabricate a makeshift short-term substitute?

Thank you again.

Bill

[mgcjag]

Hi Bill....would think it was UNF......have you tried a spare bolt.....Steve

[Bill Michigan]

Andrew, I apologize for not realizing your reply included a link to that very same part and part number.

I was so amazed by the global reach of this E-Type community--I posted in the U.S. and in less than 24 hours got the help I needed from Australia and the UK--that I failed to see the link you posted 15" in front of my nose.

Bill