Put this on the tech board, then realized maybe best to go here....

I picked up a '91 RS a few weeks ago, and it has an LO5 swapped in it, on the oil pan is a level sesor above the drain plug...appears to be metric thread...seems to fall inbetween 16 and 18 TPI via my thread gauge.

Anyone know what kinda metric bolt size I need to eliminate it?

Thing is, it a plastic threaded sensor...okay...

Fun part is the drain plug is stripped out and will not remove from its place...so in order to draing the oil I had to remove the sensor, drain a few quarts, the suck out from the sensor hole.

On putting back in the sensor, it wants to cross thread badly..after some filing, I was able to get it back in fine...but this will most likely happen next time and I'd rather find something metal (bolt/daringplug, etc) to use.

Naw, don't want to drop the pan to fix it right just yet

My 91 caprice with an L05 has no such sensor? theres just the oil pressure sensor in the block????? wonder what year it is?

I dunno, really...it was an LO5 crate engine installed 4 or 5 years ago...the oil level sensor is about 3 inches above the drinplug....

I wonder if it got an LT1 pan? Maybe I ought to check the numbers on this beast later.

I INSTALLED A GM CRATE ENGINE IN MY 89 AND THE PAN IS EQUIPPED WITH THE THREADED HOLE ABOVE THE DRAIN PLUG AS YOU STATED.
THE UPPER HOLE IS INDEED FOR A LEVEL INDICATOR USED ON BUICK ROADMASTERS AND POSSIBLY CAPRICE.

THE THREAD IS METRIC AND IF MEMORY SERVES IT IS 20 MM BY 1.5 PITCH. I GOT A PLUG AND GASKET FROM CARQUEST.

IF I RECALL, THE PARTS DESCRIPTION ON THE CHEVY COMPUTER INDICATED THE CORRECT METRIC THREAD SIZE IN THE DESCRIPTION OF THE LEVEL INDICATOR.

GOOD LUCK, JIM JOHN

Thanks Jim,

Vader mentioned the same threads size used for an LT1, but wasn't sure if the LO5 used the same thing...looks like you confirmed it for me.

Thanks again.