Bought the wrong spec oil, but might use it anyway

bainbridge

bainbridge

bainbridge

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Joined
9 Dec 2009
Posts
5,434
Location
Bristol
57 plate Vauxhall Astra 1.6 petrol, 110k miles.

I give her an oil change once per year in spring/summer. I just buy 5 litres of whatever fully synthetic 5w30 branded oil is on special offer. Today, however, I accidentally bought 5w40, which the euro car parts reg search thing said was compatible. It's GM spec.

What are the consequences of using this oil? I understand it'll be thicker than 5w30 at operating temperature and will have slightly higher compression, but will it be bad for the engine?

It's an old car, but the Mrs really likes it for some reason and it's a good runner, it passed its MOT in November with no advisories.

Thanks
 
Realistically just use it so long as it's within OEM spec as you say. by the time you top up whatever oil is in the car (assuming it burns any at all) and it breaks down over a year of use it's going to be performing differently to when you first change it over in any case....plus I'd like to imagine fresh 5w40 is better than old 5w30
 
rodenal said:
Realistically just use it so long as it's within OEM spec as you say. by the time you top up whatever oil is in the car (assuming it burns any at all) and it breaks down over a year of use it's going to be performing differently to when you first change it over in any case. I'd like to imagine fresh 5w40 is better than old 5w30
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The car does burn about a pint of oil per year, and I have about a litre of 5w30 spare, so I could put a blend in and save a litre of 5w40 for top ups.

@BennyC Indeed I could, for the same price, but if it's not going to make a difference I could save a trip there and requesting an exchange.
 
About burning oil.

Some vehicles do this, and it's normal, a pint a year depending on mileage isn't anything to worry about.

That being said, Mrs ford fiesta used to burn oil, about the same rate, it used to get serviced at a garage.

I started doing this myself several years ago, and looked up getting the right oil, specifically ford engines need certain specifications.

Ever since the car doesn't burn oil anymore.
 
Thanks for the replies. I ended up exchanging the oil to 5w30 because I was going to be passing near to the Euro car parts branch today anyway, and I'll wait until we get warm weather before doing the oil change.
 
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bainbridge said:
Thanks for the replies. I ended over exchanging the oil to 5w40 because I was going to be passing near to the Euro car parts branch today anyway, and I'll wait until we get warm weather before doing the oil change.
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Hah yea,

Warm summer day, quiet weekend, no rush, radio on, t-shirt off and maybe a cheeky beer on the side. Say hello to everyone walking by.

OR

FREEZING your **** off on a damp driveway with a filthy winter car.

I know which one I pick.

Why do things always break though middle of winter, usually the Mrs car as well........
 
BUDFORCE said:
Hah yea,

Warm summer day, quiet weekend, no rush, radio on, t-shirt off and maybe a cheeky beer on the side. Say hello to everyone walking by.

OR

FREEZING your **** off on a damp driveway with a filthy winter car.

I know which one I pick.

Why do things always break though middle of winter, usually the Mrs car as well........
Click to expand...

Yep, just take my time and enjoy it :)
 
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