Which Oil should i use?

[bad_ass_mk4]

Really quick question: I've got a H reg 318i and i'm guna pop into Halfords tonite on my way home from work to get some oil so that i can service it. What weight/viscosity oil should i get? Any particular brand? Its also done 120k..

Thanks in advance

[zimmerbimmer1]

10/40 or 15/40 will be fine for the car

[bad_ass_mk4]

ok, am i alright to use synthetic oil in the enigne? (it's the first time i've serviced it and uselessly i've left the haynes manual at home otherwise i'd have checked in there)

[Brianmoooore]

You can use synthetic if you wish, but bare in mind that a can of good synthetic will be worth more than an M40 engine.
The engine isn't fussy on grade as regards lubrication of the moving bits, but some grades may stop the hydraulic tappets working properly, and lead to a tapping engine.

[bad_ass_mk4]

haha, is that so! I didn't end up getting the oil last night, so i'll bare it in mind when i go to pick it up later.

[Speedtouch]

I've recently been using Halfords Classic 20W50 in my M20B25, the theory being that the thicker oil is better on a mileagey (122K) engine. I found it tended to use quite alot on the thinner 15/40 stuff.

[bad_ass_mk4]

Hmm i can see what you mean - I presume also, that by using a higher viscosity oil then there's less chance of the tappets starting to tap also?

[Speedtouch]

Yes, the thicker oil should help quieten down noisy/worn tappets. Most pre '90s cars used 20W50 when new, so it won't harm an old '80s engine such as in most E30s.

[bad_ass_mk4]

Thanks for the info I'll grab a bottle of the 20/50 oil tonight and swap the oil.

[Brianmoooore]

Thanks for the info I'll grab a bottle of the 20/50 oil tonight and swap the oil.

You'll pay for it at the petrol pump!

[Speedtouch]

It doesn't adversely affect the mpg on my 325i

[bad_ass_mk4]

I guess the higher viscosity will make everything have to work that little bit harder, resulting in decreased mpg.. and tbh fuel economy is one of the main reasons that im servicing the car. (to try see if fresh oil, fluids and filters can improve the mpg) as its currently averaging bellow 27mpg with mixed urban/dual carriageway driving (i know driving style affects mpg massively but this is still quite poor).

The tappets aren't tapping at the moment so i'll probably be able to get away with using a lower viscosity oil like the 15/40 instead.

[Morat]

26/27mpg average is pretty good, I'd say! I get that in an E46 330i touring and about 24 in the E30.

[bad_ass_mk4]

ouch! I'd been hoping i'd be able to get it alittle closer to 30mpg.. i guess will have to see!

[Car-Nut]

So is Halfords Classic 20W50 the way to go I have '88 325i that needs a top up

I dont normally do the oil but it defo needs some

[stonesie]

I would put 10/40 semi synthetic in it, i put that stuff in everything apart from my old escort zetec (those zetec engines are fussy and need 5/30)

My E30 appears happy enough on it, used about 1/2litre in a bit over 1000 miles and ive fixed another couple of oil leaks since then

[Car-Nut]

Yeah just had a look at my invoice Chris when he serviced and thats what it said....

I'll call to halfords tomorrow

Cheers

[e30bmlover]

i will be picking up some 10/40 gtx magnatec for my boat at the weekend... wouldnt put anything else in it.

[Speedtouch]

My M20B25 boat anchor currently has quite a bad oil leak so I'm happy to stick with the gooey 20W50 classic stuff. Also rustproofs the underside quite nicely

[Morat]

The first number is the viscosity when cold, the second is the viscosity when up to temp - what you're doing with 20/50 is putting in a oil that is thicker when cold. Surely this will just mean harder starts, and poorer oil flow until the engine warms up? I use 10/40...

[rattler]

... another vote for a fill of good 10/40 semi.

[AlpineAde]

If you run your car in temperatures well below zero degrees Celsius, say -10 or -20 for instance, then you'd be very wise using a 10w-X oil. I run a 20w-60 oil myself (Penrite HPR 30, good zinc content, too; nice for our valvetrains). In Australia I would never have cause to start my car below 0 degrees Celsius and we often have to drive the buggers at 30 degrees Celsius plus (up near the old 100 Fahrenheit isn't uncommon). A 20w-X oil will still protect your car well below 0 degrees Celsius. No difficult starts. No dramas. If anything, in Australia, the Owner's handbook has the 20w-50 oil down as pretty much the recommended one from new.

The argument about oil should really begin with "Where is the car located? What's the climate?" and work from there to questions like "Does the car use a bit of oil?" and so on....

In higher mileage cars that use a fair whack of oil I would certainly try a 15w-40 in it. And if you guys can get Penrite oil over where you are ~ give it a go! I don't know if you get the range we have but it might be worth a look.

I also like like Mobil semi-synths. A 10w-40 would be a good choice in colder climates. Bump the lower of the figures if you're using a bit of oil and see if usage decreases. Try a 15w-40 or 15w-50 and see what occurs.

[Morat]

-10 is more common in the UK than +30 !!

[AlpineAde]

I'll try and send you guys some +30 days. We get loads of them. Enough for everyone. LOL!

[Morat]

that'd be great!

[cougar]

iv just done an oil change on my silver 316i witch had a noisy cam i use halfords semi synth 10-40 but i had some FUCHS SUPERSYN 5W40 OIL 4L laying around from a service i did on a e36 so i put that in and its stoped a lot of the knocking

[jermyns]

Another member from Australia and agree with AlpineAde on the high temperature problems here. I have used a semi synth 15-40 or 15-50 oil for the last 2 years. The M20B27 is definately quiter with this type of oil but have noticed that I've had to add a half litre every 1500kms or so since the change. Had the car since new, 1986 so can attest to the low kms of the engine which is 135,00kms or approx 90,000 miles so was supprised that it uses any oil at all. No leaks BTW.