oilman

In this cold weather, it is beneficial to use an oil that has good cold start flow properties as it will get to the parts of the engine that need it far more quickly.

The "w" number which means winter is the key here and the lower the better.

It may seem odd but a 15w or 20w will struggle to get around the engine in very cold temps and I would strongly recommend a 10w or better still a 5w for better cold start performance.

90% of all engine wear occurs on cold start because the oil get thicker the colder it is which causes engine wear.

These numbers explain what I mean and bear in mind that the oil will be the following thickness at 100degC (sae 40 = 14cst, sae 50 = 18cst and sae 60 = 24cst)

At 0degC these are the numbers (thick!)

Grade.................At 0C.........At 10C...........At 100C

0W/20.............328.6cSt......180.8cSt..........9cS t

5W/40.............811.4cSt......421.4cSt..........14c St

10W/50............1039cSt.......538.9cSt..........18cS t

15W/50.............1376cSt.......674.7cSt.........18cS t

20W/50.............2305cSt.......1015cSt..........18cS t

If you are using anything more than a 10w oil, always warm the car properly before driving it as the oil needs time to circulate.

Just a word of warning really.

Cheers
Simon

Lou Lou.

Excellant info thanks

Stealth Bomber

Wow I've just realised why my engine has cranked so slowly these last few mornings! I thought it was maybe the battery or starter motor showing signs of end of life, but sounds like it's just this cold snap and my oil!

Using Mobil 1 Motorsport, that's 15w 50 innit?

Alps Pacino

i'm using fuchs 15-50 and mine has a slight top end tap when cold, only happened the last 2 days mind. Was going to change the oil this weekend so might go for a 5-40 instead

ballin

iTrader: (1)

cheers for the info!
i was using 10/50 silkolene pro as recommended so what would you suggest to drop to over winter?

silkolene pro s 5w40?

(zvh)

oilman

10w is fine for winter, the 15w is why your are hearing tapping and sluggish to crank.

Its not a problem, just allow the engine to warm that little bit longer before givving it some.

Cheers

Simon.

ballin

iTrader: (1)

gearboxman

Simon.

Incidentally, cSt; is that centistokes?
If so, that IS an education....

oilman

cst = centistokes indeed sir.

Cheers

Simon.

Stealth Bomber

Oilman, if I slung in some of the 0w-40 Mobil 1, to thin out my 15w-50 Mobil 1 Motorsport, would that be a problem?

oilman

Best not to.

Just change to a decent 5w-40 would be my advice.

Cheers
Simon

Dave McB

thanks oilman.

I keep gettin mixed up with the viscosity......cant seem to remember which way round was the thinnest.

Mine is a bit tappety on startup. il get the 5/40 in it