Mixing different brand of oils

Mixing different brand of oils

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Discussion

Spare tyre

Original Poster:

9,566 posts

130 months

Wednesday 28th October 2020
quotequote all
I’ve got a load of random amounts of oils from different manufacturers left over, donated etc. If I add it all together I’ve got enough for an oil change. Is this bad practice, or is it fine if they are all the correct grade for the motor

Cheers

Frank7

6,619 posts

87 months

Wednesday 28th October 2020
quotequote all
Spare tyre said:
I’ve got a load of random amounts of oils from different manufacturers left over, donated etc. If I add it all together I’ve got enough for an oil change. Is this bad practice, or is it fine if they are all the correct grade for the motor

Cheers
Can’t answer definitively, but when I drove an oil tanker for Castrol, management supplied the drivers with the facility to use the garage pits to service their cars, along with a constantly refilled tank of GTX.
I’d do the normal thing, and drain the sump, then refill with GTX, but a friend would just keep pouring GTX in until it was coming out of the sump into the waste oil tank the same colour as it was going in.

Andy RV

304 posts

130 months

Wednesday 28th October 2020
quotequote all
Depends on the value you put on your engine.

DailyHack

3,173 posts

111 months

Wednesday 28th October 2020
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Aslong as its same the spec/grade for car, no issues what so ever.

warch

2,941 posts

154 months

Wednesday 28th October 2020
quotequote all
DailyHack said:
Aslong as its same the spec/grade for car, no issues what so ever.
This, provided it isn't ancient and badly stored.


Tony1963

4,758 posts

162 months

Wednesday 28th October 2020
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Andy RV said:
Depends on the value you put on your engine.
Why do you say this?

warch

2,941 posts

154 months

Wednesday 28th October 2020
quotequote all
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.

Scrump

22,001 posts

158 months

Wednesday 28th October 2020
quotequote all
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.
I remember on a US car forum (might have been mustangs) that someone asked about flushing the engine when changing the oil and someone suggested running a hose into the filler cap to wash out the engine whilst it was running. The advice was followed yikes

warch

2,941 posts

154 months

Wednesday 28th October 2020
quotequote all
Scrump said:
I remember on a US car forum (might have been mustangs) that someone asked about flushing the engine when changing the oil and someone suggested running a hose into the filler cap to wash out the engine whilst it was running. The advice was followed yikes
biggrin Excellent.

My late uncle used to use diesel as engine flush when he worked as a mini cab driver, probably a lot cheaper than actual engine flush and just as effective, especially in old diesel engines which spent all days sitting in urban traffic coking up.

scottyp123

3,881 posts

56 months

Wednesday 28th October 2020
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I remember the days and it doesn't seem that long ago when you popped down to ASDA and bought a gallon of oil for £2.99 an put it in your car no questions asked, not even bothering what it said on the outside of the container. The service I did a couple of days ago I found myself obsessing over not only the viscocity of it but whether it was low saps and A or B or whatever the other many numbers and letters were in the product code. Its probably just like diesel and all comes out of the same tank anyway.

Andy RV

304 posts

130 months

Wednesday 28th October 2020
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Tony1963 said:
Why do you say this?
Because my engine is worth more than a bottle of oil.

rigga

8,730 posts

201 months

Wednesday 28th October 2020
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DailyHack said:
Aslong as its same the spec/grade for car, no issues what so ever.
Some oil is better than no oil.

As long as the grade matches what was designated by the manufacturer, then no issues.



Many moons ago I worked in the motor trade, many questions were asked about what grade oil to use in non turbo, petrol and diesel turbo applications.
They were all filled from the same bulk tank in the corner of the workshop.

Main dealer.

gazza285

9,810 posts

208 months

Wednesday 28th October 2020
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Andy RV said:
Tony1963 said:
Why do you say this?
Because my engine is worth more than a bottle of oil.
Very empirical.

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

anonymous-user

54 months

Thursday 29th October 2020
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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

2,941 posts

154 months

Thursday 29th October 2020
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Btw how often do people actually have an engine wear out or fail, due to lubricant related problems? Not that often in my experience.

loskie

5,216 posts

120 months

Thursday 29th October 2020
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I'm sure most garages will just use a "universal" bulk oil rather than have many different types of slightly different specs. Whether that's right or wrong is a different matter but they will do what achieves the best margins for them.

TRIUMPHBULLET

699 posts

113 months

Thursday 29th October 2020
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As long as its the right grade and is changed sooner rather than later (especially diesel) then all will be fine.
Leaving an expensive oil in for too long is worse than changing a cheapo every 6 months, oil holds contaminants as well as lubricating an engine, that ability degrades over time.

Andy RV

304 posts

130 months

Thursday 29th October 2020
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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.

thebraketester

14,224 posts

138 months

Thursday 29th October 2020
quotequote all
Spare tyre said:
I’ve got a load of random amounts of oils from different manufacturers left over, donated etc. If I add it all together I’ve got enough for an oil change. Is this bad practice, or is it fine if they are all the correct grade for the motor

Cheers
The only bit of that paragraph that would concern me is “donated”. Can you guarantee that the oil you have been given isn’t contaminated in some way? If it’s all in sealed containers then crack on....

Tony1963

4,758 posts

162 months

Thursday 29th October 2020
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Made up scenario

You’re away on a driving holiday, hundreds of miles from home, and one day you check your oil... oh. It looks like it needs a 0.5 litre top up. You visit the only garage in the area, and they have oil for sale but it’s a different brand. It’s also a later spec, compatible with what’s in the sump. Would you buy it, top up as necessary, and move on? Or would you do a complete oil change, filter change, and a flush?