Mixing Motor Oil

[Torquemonster]

Is it okay to mix different types of motor oil?

What i mean is totally different, different brand, different viscosity, one is synthetic and the other is semi synthetic.

but both are unused motor oil though.. i have some left over, there is about 4 litres altogether, thinking of mixing it together and using it on my car..

[Karebu]

hi, it seems to be fine surprisingly. run a google search on "mixing engine oil". yahoo and answers.com say its fine.

 

i guess if it's not a racing spec car and if you are cool with it. go ahead!

 

[Davidklt]

No issues.

[Tigershark1976]

if you search thru SG car forum, i would say majority will tell you NO... some say it might cause engine failure, some even say engine may explode...

 

Most angmoh, on the other hand, believes that mixing engine oil is perfectly fine (your may visit bitog)

 

For me, i have seen my dad mixing many diff oil in his old dutson since i was a kid...... the old car consume engine oil. so, whenever the oil level drop, he will just buy some engine oil from petrol kiosk for top up purpose... As for me, I always mixed the left over oil from the oil change (Vios only need 3L/ oil change), and once the left over oil reach 3L, i will use it on my next oil change... so far my vios millage is more than 150K and yet to explode...

[Pisces69]

Is it okay to mix different types of motor oil?

What i mean is totally different, different brand, different viscosity, one is synthetic and the other is semi synthetic.

but both are unused motor oil though.. i have some left over, there is about 4 litres altogether, thinking of mixing it together and using it on my car..

 

 

If u not fussy, then dont waste e oil.

 

Just that different oils hv different additives n im not sure if it wil hv any negative effects on yr engine.

 

Just make sure e oils r meant fr car engines n still clean n moisture free.

 

Fr me, i might add a small amt of a different oil to just top-up if my next oil change is not too long off.

[Asure7]

Actually, official answer is No .. or rather best not to.

 

Different oils have different formulations, in particular the additives used, and the ratio/proportion.

Mixing oil MAY cause the different additives to cancel out each other, and the oil will not provide the protection it is supposed to.

In worst situation, the additives react badly with each other and cause sludge.

 

If you really have to, mix oil from the same brand to reduce risks as their additives package are more likely to be the same.

[Tigershark1976]

Actually, official answer is No .. or rather best not to.

 

Different oils have different formulations, in particular the additives used, and the ratio/proportion.

Mixing oil MAY cause the different additives to cancel out each other, and the oil will not provide the protection it is supposed to.

In worst situation, the additives react badly with each other and cause sludge.

 

If you really have to, mix oil from the same brand to reduce risks as their additives package are more likely to be the same.

 

 

the official answer is from who?

[Forte3737]

the official answer is from who?

 

 

from a novice who thinks he know it all. total rubbish. still dare to say the word OFFICIAL

[Panhard]

i wouldn't personally recommend it.

 

cos its just not good practice to do it.

 

but with that said.

 

if there really is a need, for example just to top up

cos current oil cannot be found at all,

 

then its ok!

[Betweenus21]

its of course better Not to mix engine oils due to diff formulation and addictives used - which will prevent the engine oil from giving its best. However the engine will still run on a mixture of engine oils as the base is basically the same.

[Melvyn]

Actually one can mix the oils no harm. Residents of countries with different seasons also uses different oils as the seasons pass. With each change, a bit of residual oil is always left within the engine and theirs could contain residues of easily 5 or 6 types of oil.

The only thing to take note of is that oil with polyglycol does not mix with mineral oils. But offhand I can't think of any brands that contains that since most are polyalphaolifins which can mix.

Logic aside, personally I would not mix the two together as the car is one of my biggest spendings. For me, I'll rather spend the extra 30 - 40 bucks and drive without any lingering fears & doubts - mostly self-induced and baseless I assume - that I fcuked up my engine

[Vhtfhwlego]

Fr me, i might add a small amt of a different oil to just top-up if my next oil change is not too long off.

Just do a little sample taste bit by bit lor.

[Aaronlkl]

ok but not recomended..

[Good-Carbuyer]

Is it okay to mix different types of motor oil?

What i mean is totally different, different brand, different viscosity, one is synthetic and the other is semi synthetic.

but both are unused motor oil though.. i have some left over, there is about 4 litres altogether, thinking of mixing it together and using it on my car..

No objection to save a few dollars from buying new bottle

[Tigershark1976]

its of course better Not to mix engine oils due to diff formulation and addictives used - . However the engine will still run on a mixture of engine oils as the base is basically the same.

 

 

any proof of your claim?

[Asure7]

the official answer is from who?

 

From Castrol and my beemer car manual.

To be more specific, its ok to mix a little for top up purpose and not entire oil change, and same brand is used. The reason is already stated in my previous post.

 

From my own personal point of view, of course you can mix different brands provided you know what you are doing e.g. Group III/IV/V based? Additive package used?

The engine wont die overnight anyway, just that the intended protection may not be achieved and you may need shorter OCI (thats why better for top up purpose).

Short example: BMW now requires Longlife-01. If mix with Longlife-98, which obviously offer much less protection than LL-01, the resultant mixture cannot pass Longlife-01 tests, and you cannot adhere to the same oil change interval intended for pure LL-01 oils.

 

Jap engines are not that "sensitive" in the way most only required API-SL rating, and today's modern oils far exceeds that standard. But conti engines are very particular about such things and you probably do not want to take risks with that especially when they have longer OCIs.

If you are thinking that in Singapore, we change cars so frequently anyway, so what if there is a little engine "damage"?... then you are probably right. Sludge? just do an engine flush.

 

Some oil manufacturers like Castrol offer Engine Warranty and guarantee engine life if you use their products. Obviously they will void that if you mix brands. Which was why I mentioned "Official".

 

Maybe we just have different expectations.

When I said "No", i meant it in the sense that we cannot expect the mixture to perform optimally with the original intended protection.

But if you mean can the engine still run even if it loses some performance? Is it ok in the short term? Then my answer will be "yes".

Edited November 12, 2010 by Asure7

[Jamesc]

Short example: BMW now requires Longlife-01. If mix with Longlife-98, which obviously offer much less protection than LL-01, the resultant mixture cannot pass Longlife-01 tests, and you cannot adhere to the same oil change interval intended for pure LL-01 oils.

 

Jap engines are not that "sensitive" in the way most only required API-SL rating, and today's modern oils far exceeds that standard. But conti engines are very particular about such things and you probably do not want to take risks with that especially when they have longer OCIs.

This is not an official answer.

 

All this example shows is if you want an extended OCI you need to use an extended life oil.

 

If there were 2 brand different brands that meet BMW Longlife-01, does that mean you cannot mix them?

 

Some oil manufacturers like Castrol offer Engine Warranty and guarantee engine life if you use their products. Obviously they will void that if you mix brands. Which was why I mentioned "Official".

This is also not an official answer.

 

If you mix Castrol and brand B, Castrol is not liable for any defect caused by brand B simply because you are using another company's product.

 

If you mix Castrol EDGE and Castrol Magnatec and you use within specified directions Castrol is liable.

 

 

 

[Asure7]

I don't quite understand what you meant by "this is not an official answer", or did you misunderstood what i posted as personal opinion.

 

Just to make it clear.

The examples i posted are obviously my own personal view, of course that is not an official answer, but a personal opinion.

 

The official part of my answer was:

Castrol told me NO mixing of different brands. Anything happen, your own responsibility.

My car manual says NO, unless you really have to.