Night time under the shade tree. Working on the 1986 244GL, estimated 260K miles.

Oil change. New Mann filter. First quart in, OK. Second quart, the oil didn't look "golden" like the first quart did, even with poor lighting and back-lit.

Looked at the color with trouble light up close - "It's Green!" Aauuugh!! Look at the label - Havoline 2-cycle for the chain saw.

Dunno how that bottle got in with the rest of the Havoline 20W-50. Same brown bottle, same red cap. I just grabbed four bottles out of the case without reading labels. Rats! Maybe I mixed the 2-cycle in when storing oil, the case was open. Maybe the 5th quart that all my 240s have on board was the 2-cycle.

So I added 1/2 quart of the right stuff, and then put in quart #3 and #4. So the oil is 12.5% 2-cycle and 87.5% 20W-50, all Havoline.

Car is blocking drive for wifemobile, which must away early up Thursday. So I cranked the 1986 with no 25amp fuse for 10-15 seconds. Then put in fuse and started it up.

Seemed OK, ran smooth and went into closed loop (it's 65F here), but I can hear a low-in-block sound that (1) I am not certain was never there before, and (2) sounds like a rod or main bearing knock.

Options are A drain the works, and put in all new oil, keep old filter. B drain the works, put in all new with new filter, C run it as is for 3,000 miles and do a regular scheduled oil+filter change then.

Can the 1/2 quart 2-cycle oil damage anything? Damage the bearings? Burn up in the combustion chambers in a damaging way? Screw up the flame trap? FUBAR the plugs?

Can you provide some insights that I don't have? There are several Oil Experts who are members here.

Thanks in advance, as always,

Bob

:>)