Mobil 1 5w-50 Or 10w-30

[Beef]

Hey ladz,

just a quick question on what the actual difference is between these?

and which one is going to be better for an R33 with around 100,000kms?

Beef

[Busky2k]

If your car is relatively stock and doesn't use much oil, I'd go the 10W30 because its thinner. The 15W50 is more meant for cars that use oil/hits the track etc.

[wilch]

Ummm... I think he said 5w50.

Which is what I use, over filled (to the bottom of the bump on the stick) ofcourse.

I think 10w30 would break down too early in an RB turbo engine (engine gets too hot for that oil).

[Busky2k]

Sorry yes 5W50. Same thing really. Still nice and thick.

The M1 10W30 won't break down in an RB. Its fully synthetic PAO based oil so it can handle the stress without breaking a sweat. Hell Nissan's OEM oil is 7.5W30 mineral stuff so if that can do the job...

Your average RB doesnt run any hotter than any other engine, why would you say that? The turbo is water cooled anyway so the turbo isn't as hard on the oil as the days of old.

[95SKY]

Ive ran both 5w50 and 10w 30 in a rb26 I didnt notice any difference on start up etc or even after 5000k's

Im pretty sure they recommend 10w30 for the RB's even Nissan??

[Guest 40th-edition]

i run 10w30 because i get it from work.. does the job and have no probs with it at all..

the numbers given to the weights of the oils r over rated ne ways... 50 is a large cold weight and 0 is just bull shit.. just oil componeys claming crap ( i know they go through sia testing)

[mad082]

a lighter oil is better if you do a lot of short driving where the engine doesn't heat up as quick. i run 10w-30 and when the car is cold the oil pressure is much higher then when warm.

[djr81]

i run 10w30 because i get it from work.. does the job and have no probs with it at all..

the numbers given to the weights of the oils r over rated ne ways... 50 is a large cold weight and 0 is just bull shit.. just oil componeys claming crap ( i know they go through sia testing)

50 is not the cold weight. It is the measure of the high temperature viscosity.

As for the numbers being crap, it is easy to compare the difference between two grades. Just tip some out of the bottle - it will suprise you how different they are.

Essentially, to compare the 5W50 to the 10W30 they are basically the same oil, just with different viscosity modfiers. The 5W50 will be "thinner' when cold & "thicker" when hot. This is a relative thing as obviously the oil's viscosity will decrease as it gets hotter.

At the end of the day you will be marginally better off with the 5W50 because it is more stable, most noticeably when hot.

[satanic]

I'm glad I serviced my car last night with 5W-50

[Busky2k]

However you will find that say, Mobil 1 10W30 will be significantly thinner than the Mobil 1 5W50 at all temperatures above -10C. Don't let the W rating fool ya!

[djr81]

Maybe if someone had a graph of viscosity versus temperature that could be posted it would be easier to explain. Unfortunately I can't find one.

[Topaz]

I am running Mobil1 5W50 at the moment and just bought another 5L on Saturday. Never had a problem since my change in February.

[mad082]

is it 5W50, or 5W30? cause 5W50 sounds like a pretty thick oil to me.

[Beef]

is it 5W50, or 5W30? cause 5W50 sounds like a pretty thick oil to me.

its definitley 5w-50.... but u can buy 10w-30 aswell....

when is oil at its thickest? i never drive my car for longer than 50 mins at a time, i dont go on long trips.... so what would be better for me?

im only ever doing little trips to work and stuff... never big road trips..

Beef

[mad082]

whether you drive for 20 mins or 5 hours, once the car car has come up to operating temp the oil temp shouldn't rise (unless you are flogging it). normal oil gets thinner as it got hot, but multigrade oils are designed so they don't thin as much.

Edited August 8, 2006 by mad082

[mad082]

just doing a bit of research, normally oil thins at higher temp. multi-grade oils have polymers that stop it hinning too much (so its thin when cold, and not too thin when hot). the dissadvantage with high range oils (big gap between 1st and 2nd numbers) is that they are more prone to breaking down. it is the oil that lubricates, not the additives, so the less additives, the better.

[Lost]

Hi Guys,

There was mention above of filling oil past the MAX to the BUMP. I was told by one mechanic that this reduces the change of oil surge and is ok but by another mechnic that filling past MAX on the dipstick can cause potential damage. Can I get some sort of common consensus on whether this is ok?

Cheers.

[djr81]

Skylines are notorious for oil surge killing RB motors. GT-R more so than anything else. Overfilling the sump helps prevent it. Not sure how much to do so on a RB25, but an extra litre on an RB26 is fine.

[J_R32]

how much can u overfill?

everyone knows too much oil will result in white smoke out of the exhaust...happened to me once when i changed oil on a mr2 3sgte.