Engine oils, safe to mix ?

KaiserBill

I need to top up the oil in my engine. It has fully synthetic in it.


I do not have any fully synthetic oil-but I have lots of semi-synthetic.


Would it be safe to now top up using semi-synthetic ?

Netwizard

What car is itt?

I've mixed all sorts in the past but my car is old, and the oils available today are much better today than they were 17 years ago no doubt.

There are lots of conflicting opinions online about mixing oils, but mobil 1 site says:

[quote=Mobil_1[/quote]Can different synthetic motor oils be mixed together?

Mobil 1 with SuperSyn™ is fully compatible with conventional motor oils, semi-synthetic motor oils and other synthetic motor oils, should it be necessary to mix them. But the superior performance of Mobil 1 with SuperSyn™ will be reduced by diluting it. [/quote]

the only exception is some diesels can be quite sensitive to what oil they take, some VAGS and Fords take specific oil.

KaiserBill

Netwizard wrote: »

What car is itt?

I've mixed all sorts in the past but my car is old, and the oils available today are much better today than they were 17 years ago no doubt.

There are lots of conflicting opinions online about mixing oils, but mobil 1 site says:

Can different synthetic motor oils be mixed together?

Mobil 1 with SuperSyn™ is fully compatible with conventional motor oils, semi-synthetic motor oils and other synthetic motor oils, should it be necessary to mix them. But the superior performance of Mobil 1 with SuperSyn™ will be reduced by diluting it.

the only exception is some diesels can be quite sensitive to what oil they take, some VAGS and Fords take specific oil.[/QUOTE]


It is an Astra, 03 plate, 1.6 8v. Petrol.


As you say, lots of conflicting views on the internet.

Netwizard

KaiserBill wrote: »

It is an Astra, 03 plate, 1.6 8v. Petrol.

You will be fine mixing it in that

londonTiger

By conflicting opinion you mean oil snobbery. As long as it's the correct oil for your car there shouldn't be any problems mixing it.

Westmead_Fan

what grade is in it & what grade do you want to put in it is the important question?

KaiserBill

Bit of a long story. For years I have been changing my own oil and filter. I always used Vauxhall / GM genuine 10W40 semi synthetic. I always bought it in bulk to save money, which is why I now have lots.


On here I read about the Vauxhall Masterfit Service Club, so I joined


They had a special offer on a service, I think it was about £120 that I paid.


I expected them to use semi synthetic-they didn't .


All it says on the invoice is, engine oil fully synthetic 4 litres. Part no.93165008. Obviously this was a Vauxhall main agent that I went to.


So I was wanting to use some of my GM semi synthetic oil to top up the GM ( unknown ) fully synthetic oil.

Iceweasel

If the grade is right, then there will be no problem in your petrol engine.

It's in modern diesels with Diesel particulate filters that you need to be careful in getting an oil for that application, as well as getting the numbers right.

Stoke

As far as I've always understood, there's no problem mixing semi with fully synthetic oils, however the added protection of fully synthetic will obviously not be present.

There's a lot of oil snobbery on the Internet. I wouldn't listen.

KaiserBill

Since I switched to fully synthetic oil I have noticed that it is now using more oil. Perhaps because it is " thinner ".


The car has only done 75,000 miles.

Stoke

KaiserBill wrote: »

Since I switched to fully synthetic oil I have noticed that it is now using more oil. Perhaps because it is " thinner ".


The car has only done 75,000 miles.

Same grade of oil?