Mixing different brand of oils

[Chris32345]

warch said:

I can remember a classic PH thread where someone was obsessing about having topped up their car with the wrong grade or oil. People were replying with all sorts of hysterical remedies, like draining the engine twice and changing the filter (just to be sure).

People (usually men) tend to be a bit OCD about stuff like engine oil, fuel and additives, presumably because of years of advertising.

Weirdly many bikers use fairly common or garden 10/40 semi-synthetic oil despite having incredibly high output, high revving engines. I only went with posh oil for my own bike because the (wet) clutch works better with it.

car engine's tens to be more complex and can often use the oil to do other things turbo's hydraulic tappets multi-air /ingenium tech using the oil to control valve timing duration and opening size

Compared to rather simpler bikes engine's allthrough often higher stressed due to high rmp

[gazza285]

Andy RV said:

gazza285 said:

Very empirical.

Do you know of any valid reason not to mix different brands of the same grade of oil?

To be honest, no. Do you have a valid reason to support the mixing of different brands?

I don’t see it as a major risk however if it’s a car you care about I see no logical reason to skimp on buying a bottle or two of oil.

I do believe that was addressed by Berw in an earlier reply...

Berw said:

Part of the Api spec is that all oils to that spec can mix, oil grades are very wide some oils may be at the top end of the spec others towards the bottom, but they must be capable of being mixed.

[warch]

Chris32345 said:

ar engine's tens to be more complex and can often use the oil to do other things turbo's hydraulic tappets multi-air /ingenium tech using the oil to control valve timing duration and opening size

Compared to rather simpler bikes engine's allthrough often higher stressed due to high rmp

Bikes also generally have shared engine/gearbox oil and a wet clutch, but I absolutely agree that turbo engines do place a lot of strain on the oil.

[Blue62]

I’ve just changed car and the new one drinks 5W/40. My previous car used 5W/30 and for some reason I’ve got about 4 litres of the stuff in the garage. My view is that the lower viscosity will be fine in my new car, I’m not that anal (happily mix brands) but would appreciate others opinions.

[DailyHack]

Blue62 said:

I’ve just changed car and the new one drinks 5W/40. My previous car used 5W/30 and for some reason I’ve got about 4 litres of the stuff in the garage. My view is that the lower viscosity will be fine in my new car, I’m not that anal (happily mix brands) but would appreciate others opinions.

If it's the correct spec (for your car) won't make a difference what viscosity, unless your running a rather special machine that requires X.

I quote often change viscosity pending what's cheapest...but always the correct spec required.

[FK]

In my experience, this should not pose too many problems.

After all, every time you take your car to a garage to do an oil change, it is not a guarantee that you or the mechanics will get 100% of the old oil out. Much of this depends on the mix, but as long as the both brands meet the required spec for the engine in question, I would be extremely surprised if it's a cause of engine failure. Needless to say, this is far far better than not having enough oil.