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View Full Version : which oil 5w-40 or 5w-30

bluecon75
18th May 2010, 15:31
my 2002 diesel tourer is booked in for an oil change at a bmw indy garage - they say the bmw engine should use 5w-30 oil but on the web it says 5w-40

so which is correct???
pab
18th May 2010, 16:13
10w-40 or 15w-40 to spec. ACEA A3.

that is what mgrover recommended.
T-Cut
18th May 2010, 16:47
..and B3 for diesels.

TC
Rov5
18th May 2010, 16:49
10W-40 Semi Synthetic to last posts spec
Devilish
18th May 2010, 18:30
Both are correct, the rover spec is correct, and the BMW reccomendation is correct. I have used 5W30 fully synthetic in all my 75's, they were all high mileage (130k+) when bought, running on fully synthetic anyway. Except my tourer that ran on semi, I bought it at 40k and changed it to fully 5W30 immediately.

The caveat is that your engine must be in good working order and not be leaking and runs smoothly right now. If you've been driving around with mineral oil in your engine for years, don't switch to synthetic oil without preparation. Synthetic oils have been known to dislodge the baked-on deposits from mineral oils and leave them floating around your engine - not good. It's wise to use flushing oil first. Switching to a thinner synthetic oil can cause piston rings to leak and in some very rare cases, piston slap or crank vibration. Gaskets and seals have been known to leak when exposed to synthetic oils. rare occurrences, but worth bearing in mind. much depends upon mileage, type of oil used, and proactive servicing.
JohnDotCom
18th May 2010, 18:32
Yes I've used Mobil1 Diesel from day one.
Seems great to me with no problems and believe thats even lower (5w30 or 0w30)
bluecon75
19th May 2010, 19:05
well i've had a service today, 5w-30 oil was used. also had brake fluid change, coolant check and top up, quick inspection of underneath and computer reset all for £135 which i didn't think was to bad

the car seems smoother and a little bit more poke
pab
19th May 2010, 19:12
well i've had a service today, 5w-30 oil was used. also had brake fluid change, coolant check and top up, quick inspection of underneath and computer reset all for £135 which i didn't think was to bad

the car seems smoother and a little bit more pokewhy did you opt against the 10w-40 ?
JohnDotCom
19th May 2010, 20:46
Bit thick on Cold mornings...........:getmecoat:
rossocorsa
19th May 2010, 22:16
on the 'other side' as it is called this same question caused much controversy

http://forums.mg-rover.org/showthread.php?t=364318

...and incidentally why on earth can't we just say '.org' what is all this 'other side' BS about????