26-04-2020, 10:54 PM
Until the 50s and additive oils gooey sumps were not uncommon. Our Seven used for short runs used to accumualte an inch of grey sludge. Old filters in dumps were often gooey blobs. i recall an article in Pop Mechanics about police cars which missed oil changes. Were gooey as picture. Colleagues have encounterd fluctuating oil pressure traced to thick residue in sump of a mid 1950s Vauxhall and a later Rover 100. OK with justthe sumps cleaned but cars had filters. The oil firms used to claim that modern oils would not strip varnish like deposts, but I suspect now do.