Topic: oil useage in 41 super deluxe and oil pan question


fordEFV8    -- 04-19-2026 @ 7:16 PM
  New to the form. Have read posts regarding the proper engine oil(s) to use. A new owner to the car so a rookie. The small but original "Service Data Handbook" says 30 wt, 40 wt depending on ave temps. I also read somewhere that oil for a diesel engine was good because of some difference in the modern 30 wt etc that is not the best for these old cars??? I purchased some 15W-40 for diesel engines but have not changed oil yet. Any comments on this diesel oil thing?

Oil drain plug is large and set on the bottom at the lowest level of the pan. Approx 4-5" toward the rear of the car from the drain plug and at the same level in the pan is a +/- 1/8" diameter hole (doesn't appear a corrosion type thing but a deliberately drilled hole)?? In that hole is a very loose cotter pin, ears bent out, no "stopper", it would seal nothing. Took out drain plug and drained maybe 1 1/2-2 quarts!! Looks like almost a disaster! Is the 1/8" hole there for a purpose, I can't imagine why it's there?

Thanks Sam K.


carcrazy    -- 04-19-2026 @ 8:09 PM
  If this were my car, I would use a conventional SAE 30 High Detergency motor oil with Redline Engine Oil Break-In Additive. The reason for using this additive is to have the proper amount of ZDDP in the engine to reduce camshaft and valvetrain wear.

Most modern motor oils for cars and trucks, including Diesels, no longer include the ZDDP additive package as it contaminates the catalytic converters required to meet the modern emissions standards.

Modern engines do not require ZDDP as they all use roller elements in the valvetrain, either roller tappets or roller finger followers.


carcrazy    -- 04-19-2026 @ 8:16 PM
  That small hole in the bottom of the oil pan beneath the clutch area is to allow engine oil which leaks past the rear main bearing to escape without contaminating the clutch or pressure plate. The cotter pin is in the hole to keep it from getting plugged up by dirt or other contaminants.


nelsb01    -- 04-19-2026 @ 10:07 PM
  Since you did not mention that your engine was a current rebuilt or just a good old used engine, I would not suggest detergent oil.
It may break loose some of the sludge and such that is currently in your engine and that sludge may clog some of the oil passages in the engine.
If you are unsure, I would find some non-detergent oil and use that. Straight weight 30.




fordEFV8    -- 04-20-2026 @ 10:17 AM
  Thanks very much for the reply. I don't believe it is a recent rebuild but I will use the oil you recommended. Exactly the information I needed!!


fordEFV8    -- 04-20-2026 @ 10:22 AM
  ok then non-detergent 30 wt is preferred then. Engine may have been rebuilt in the past as it is nicely painted as the car in general is has nice appearance. Another reply suggested detergent but for a rebuilt engine? Thanks


fordEFV8    -- 04-20-2026 @ 10:28 AM
  That cotter in/hole thing had me stumped. I thought it might be a pressure relief thing but that didn't really sound correct. Thought it might be for an "overflow" type thing but again I didn't know. This answers the question. Thanks, again this answers a novices question!!

Sam K.


fordEFV8    -- 04-20-2026 @ 10:58 AM
  After your reply I finally found pictures of the oil pan I have. I thought perhaps and the pictures confirmed a partition in the pan that separates the oil pan reserve holding area from the clutch drip pan area. Had looked for a clear picture before posting. Found good ones this afternoon on Ebay???!! Thanks again.


nelsb01    -- 04-20-2026 @ 3:19 PM
  Yup, Early V-8s are just like Harley Davidson motorcycles. Every time they park some place they mark their territory.

But, as you will find out, enjoying it whether or not it leaves a drip, is what it is all about.


TomO    -- 04-20-2026 @ 3:29 PM
  I have to disagree with the oil recommendations. I would use a good 10w-30 or 20w-40 oil detergent oil. Non-detergent oils went out in the 1960's and the modern oils lubricate much better than the oils that were available when your engine was built..

Detergent oils do not loosen sludge, they just help prevent the build up of varnish and other contaminants in the engine. They may help slightly in removing sludge.

The multi-viscosty oils maintain a consistent viscosity over a wide range of engine temperatures giving the engine better lubrication. A single viscosity oil is thick when cold and thin when hot, giving uneven engine protection.

Tom


carcrazy    -- 04-20-2026 @ 7:55 PM
  If you ask 100 old car enthusiasts what oil to use you will get 100 different answers!

My recommendation is to use Pennzoil straight SAE 30 weight detergent motor oil with API Service SN or later rating along with Red Line Engine Oil Break-In Additive.

The reason for using the detergent oil is it has many more additives built in to reduce friction and improve the function of the oil's lubricating properties to reduce friction and promote longer engine life.

The reason for using a single viscosity SAE 30 grade instead of a multigrade is that the base stock viscosity of the oil is thicker and not so likely to either leak out of the engine or slip past the rings to be burnt in the combustion chambers.

If your car has an oil filter, be sure to change it at every oil change.


fordEFV8    -- 04-22-2026 @ 10:23 AM
  Went with the 10W-30 you recommend but did add a few oz. of ZDDP.


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