0w40 vs 5w40

[jtaylor2005]

Alright guys. I am new here. Decided to sign up to pistonheads as it always seems to have some great results come up when I google stuff and people seem very informative So Hi

Quick question. It's getting cold now. My car is due a service. Its a 2.0l HDI engine and currently I use 5w40 oil. Do you think the extra cost of 0w40 which is about £6 more for 5L is worth it for the better flow in the cold weather and during warm up times?
HDI's are known to take ages to warm up even with working thermostats.

What do you guys reckon? Thanks
Jack

[TEKNOPUG]

Not unless you are regularly experiencing temperatures of -25c and lower, no.

[jtaylor2005]

There is a difference in viscosity at 40c as well. And as the temp lowers it will be a bigger gap so down to -5 would be a larger gap.

0w40 http://www.mobil.co.uk/uk-english-lcw/carengineoil...

5w40 http://www.mobil.co.uk/UK-English-LCW/carengineoil...

[kambites]

Unless you do almost all your driving on a cold engine, I think the difference in wear is probably insignificant; it might make the car slightly easier to start though.

[MDMA .]

type your reg in here and it will give you all the info you need -

http://www.opieoils.co.uk/

[TEKNOPUG]

You also increase the amount of oil that you will burn on a higher mileage engine, running oil that is too thin.

[TooMany2cvs]

jtaylor2005 said:

Quick question. It's getting cold now. My car is due a service. Its a 2.0l HDI engine and currently I use 5w40 oil. Do you think the extra cost of 0w40 which is about £6 more for 5L is worth it for the better flow in the cold weather and during warm up times?

The first figure is the nominal viscosity at 0degC. The 0w40 is a bit thinner than the 5w40.
The second figure is the nominal viscosity at 100degC. They're both the same. That doesn't mean they're absolutely identical, but it does mean that they're broadly similar - and the precise viscosity will vary from brand to brand, spec to spec within a consistent viscosity. Some 5w40s will be almost as thin, cold, as some 0w40s.

Both will, obviously, be much thicker cold than they are hot. Both will, obviously, start to warm up and thin quite quickly once the engine's started - even if the engine doesn't get to 80deg coolant, much less oil, temp within a couple of minutes.

[jtaylor2005]

So with the in mind. And the fact they probably use a much better proper fully synthetic base stock for an extra £6-7
Are there any negativrs to using it?

[jtaylor2005]

TEKNOPUG said:

You also increase the amount of oil that you will burn on a higher mileage engine, running oil that is too thin.

The oil doesn't get any thinner than normal at high temperatures it just starts off thinner when cold

[TEKNOPUG]

jtaylor2005 said:

TEKNOPUG said:

You also increase the amount of oil that you will burn on a higher mileage engine, running oil that is too thin.

The oil doesn't get any thinner than normal at high temperatures it just starts off thinner when cold

That's my point. An older engine will take a while to heat up and expand. Meanwhile the thinner oil is escaping past the clearances.

[jtaylor2005]

I don't see it causing that huge of a difference oil consumption wise though

[ging84]

TooMany2cvs said:

The first figure is the nominal viscosity at 0degC. The 0w40 is a bit thinner than the 5w40.
The second figure is the nominal viscosity at 100degC. They're both the same. That doesn't mean they're absolutely identical, but it does mean that they're broadly similar - and the precise viscosity will vary from brand to brand, spec to spec within a consistent viscosity. Some 5w40s will be almost as thin, cold, as some 0w40s.

Both will, obviously, be much thicker cold than they are hot. Both will, obviously, start to warm up and thin quite quickly once the engine's started - even if the engine doesn't get to 80deg coolant, much less oil, temp within a couple of minutes.

the winter grading is actually a lot more technical, it has to pass a max pumping viscosity test at a given temperature that goes up 5 degrees with each grade.
0W is -40, 5W is -35.
There is also a cold cranking simulation test, which gets even more technical. The temperature and the max viscosity are different for each grade, and the temperatures are not the same as for the pumping test.

[GC8]

jtaylor2005 said:

I don't see it causing that huge of a difference oil consumption wise though

Theory and practice can differ though. I have a 944 Turbo that uses as much 5W as it does petrol. Oil use is minimal with 10W.

Conversely I have a series one 944 which doesnt use a drop of 5W Pro-S. My 2.7l series two also used a lot of 5W but didnt use any 15W.

[opieoilman]

jtaylor2005 said:

Alright guys. I am new here. Decided to sign up to pistonheads as it always seems to have some great results come up when I google stuff and people seem very informative So Hi

Quick question. It's getting cold now. My car is due a service. Its a 2.0l HDI engine and currently I use 5w40 oil. Do you think the extra cost of 0w40 which is about £6 more for 5L is worth it for the better flow in the cold weather and during warm up times?
HDI's are known to take ages to warm up even with working thermostats.

What do you guys reckon? Thanks
Jack

Hi Jack

What Ging84 has said above is absolutely spot on, and there are lots of bits of technical information about oils that can be very useful, but they can end up confusing the majority of people. Using a 0w-40 or 5w-40 in a HDi is fine, either will give plenty of cold start protection in the UK. The main advantage of going for a 5w-40 is there is a larger range to pick from, so there's something to fit most budgets. With the 0w-40, they tend to cost more than a 5w-40, but are usually made with decent quality basestocks, so there isn't a budget option.

Cheers

Tim

[jtaylor2005]

Cheers fellas. I was thinking for cold start protection but I'm also curious as to how much it would effect mpg as well

[cpjitservices]

I used to use 5w-30 in my 2.0 HDI Picasso and it hardly ever used a drop. I was at 138k miles. Regular changes when it got the that sort of mileage.

[Ozzie Osmond]

All other things being equal there's practically no difference between those two specifications for the UK.