Hey thanks.

I plan to pull the plugs and dist cap to inspect.

You are right it may just be a plug. But the plug boots look like they need a gimmick to pull off w/o damaging them. I have a basic plug boot puller 'plier' cheapo but it really does not fit toward bottom for a good grip...

Dist cap: I did a dry run with a 5mm allen wrench but the lower hex nut is in a position where the allen wrench can not rest inside without the handle being avaivalble to torque it counterclockwise. It rest up onto the cap bottom or nothing.

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD