I agree.













Mixing oils should not cause a catastrophic failure. What would happen if you had your oil changed by an indy and later you needed to add oil while on a trip. are you going to search for the EXACT oil he used? NO, just put in a quart or 2 of a suitable oil of the viscosity recommended for your vehicle.

In Australia, there are VERY FEW oil blenders - companies who blend lube oils for the different oil brands. They blend to the viscosity and Grade of oil. Different oil brands require different additives (just like perfume in soap - the soap is the same, just the perfume differs). These additives are in MINUTE quantities. Most of the oils, of a particular grade and viscosity range, are exactly the same, apart from the minute amounts of the Brand-specific additives.

So if you but a gallon of 10W40 from Shell and the same from Castrol, then they are almost exactly the same oil, just one has Shell flavourings and one has Castrol flavourings.

There is no problem for them to be mixed.

Blending different viscosities does not average the viscosity ratings, but it doesn't matter much unless they are totally different viscosity ranges.

Blending Synthetic with Non-synthetic is a BIG "No Comment" here.

__________________
Tony from West Oz.
Fatmobile 3 84 300D 295kkm Silver grey/Blue int. 2 tank WVO - Recipient of TurboDesel engine.
Josephine '82 300D 390kkm White/Palamino int.
Elizabeth '81 280E, sporting a '79 300D engine.
Lucille '87 W124 300D non-turbo 6 cylinder OM603, Pearl Grey with light grey interior


Various parts cars including 280E, 230C & 300D in various states of disassembly.