Mobil 1 0w-40 vs Castrol 10w-60
 

which 1? i can get them both from work with a 5 finger discount, but unsure which would be best... for a 95 wrx with 97k and 290bhp

0 Grade oil is a no no, Edge sport 10/60 is the way to go.

as above 0 is a no no i used mobile 1 10-50 or 15-50 last service

yup, 0w is no good for scoobies.

The correct grade is 10w-40 so 10w-60 is not suitable for your car.

The oil needs to be 14cst at 100degC and the 10w-60 is 24cst!

This is 70% thicker than needed.

The 0w-40 is closer to what's required technically.

Cheers
Guy

Correct me if I'm wrong, but anit some scoobs had engines fail with using 0-40. So technicaly thicker is better then thin yes.

what is required technically and what is tried and tested are two entirely different things.

It's the 2nd bit that is the thinnest, about 20 times thinner than the "w" number which is the cold crank performance.

40 is thinner than 60 etc

Surely the thicker the oil the better?

Although it is true that heavier viscosity oils (which are generally thought of as being thicker) will hold up better under heavy loads and high temperatures, this doesn't necessarily make them a better choice for all applications.

On many newer vehicles only 0w-40, 5w40 or 10w40 engine oils are recommended by the manufacturer. If you choose to use a higher viscosity oil than what is recommended, at the very least you are likely to reduce performance of the engine. Fuel economy will likely go down and engine performance will drop.

In the winter months it is highly recommended that you not use a heavier grade oil than what is recommended by the manufacturer. In cold start conditions you could very well be causing more engine wear than when using a lighter viscosity oil.

In the summer months, going to a heavier grade is less of an issue, but there are still some things to be aware of.

Moving one grade up from the recommended viscosity is not likely to cause any problems (say from a 10w40 to a 10w50 oil). The differences in pumping and flow resitance will be slight. Although, efficiency of the engine will decrease, the oil will likely still flow adequately through the engine to maintain proper protection. However, it will not likely protect any better than the lighter weight oil recommended by the manufacturer.

Moving two grades up from the recommended viscosity (say 10w40 to 10w-60) is a little more extreme and could cause long term engine damage if not short term. Although the oil will still probably flow ok through the engine, it is a heavier visocosity oil. As such it will be more difficult to pump the oil through the engine. More friction will be present than with a lighter viscosity oil. More friction will be present than with a lighter viscosity oil.

More friction means more heat. In other words, by going to a thicker oil in the summer months, you may actually be causing more heat build-up within the engine. You'll still be providing adequate protection from metal to metal contact in the engine by going with a high viscosity, but the higher viscosity will raise engine temperatures.

In the short run, this is no big deal. However, over the long term, when engine components are run at higher temperatures, they WILL wear out more quickly. As such, if you intend on
keeping the vehicle for awhile, keep this in mind if you're considering using a heavier weight oil than the manufacturer recommends.

The best advice is to is to stay away from viscosity grades that are not mentioned in your owner's manual or seek professional advice as depending on use, other grades may be recommended.

Cheers
Guy

you are re-cut and pasting something which is general and not specific to subaru engines.. and then suggesting to seek advice from a specialist/professional.. where else will you find several thousand owners whom have been there and done it and got the tshirt and paid for rebuilds and found that 0w40 is no good and that the recommended oils are far from correct.

Simon

I am not advocating the use of 0w and never have on scoobynet, 5w yes but not 0w.

I am concerned about the use of a 60 grade over a 40 or even a 50 grade!

The "w" number is the cold crank performance, the second number is the one that concerns me as 60 is 70% thicker than recommended at high temps which could lead to problems in the wrong application.

Look at the viscosity (thickness) numbers, it's not rocket science.

Grade...........0degC............10degC......40deg C............100degC

5w-30...........654............... 338.............74................12cst
0w-40...........665............... 354.............82................14cst
5w-40...........874................440............ 91................14cst
10w-40.........842 ................430.............91............... 14cst
10w-50.........1034................537............116. ..............18cst
15w-50.........1535................735............135. ..............18cst
10w-60.........1253................795............165. ..............24cst

Cheers
Guy

Whats the best oil for a modified car with badish compression? Still 10w40? I've read (and on the back of the bottles) that 10w60 is only suitable for performance cars running regular track and drag blasts. Is the miracle N/A engine cure Ametech worth using or could it cause turbo failure?

maybe you should just stop stealing from work.

Dont touch Ametec, will just do more harm then good.

Does it use much oil?

Cheers

Guy

ha i should really shouldn't i :D

oh **** im running mobile 1 0w-40 in my 95 wrx. is 0w-40 really that bad?

Tizer, do an oil/filter change asap, and stick in 10W-40 or 10W-50 and be done with it. I have ZEN-supplied Millers CFS 10W-40 in my MY93 WRX v.1 EJ20G.

I disagree, 0w-40 is fine and Mobil is a good quality oil. Only reason to go thicker is if it suffers excessive oil consumption. These were recommended 5w-30 originally so 0w-40 is fine.

10w-60 is too thick when upto temp.

Cheers

Guy

What would Scoobynet be without a good arguement about oil viscosity :luxhello: Lots of us were getting withdrawl symptoms;)

JohnD

0/40 is not fine end of, change asap. I was 1 of the scoobynet peeps that had to have a rebuild do to mobile 1 0-40. If peeps would like to post saying they had rebuilds due to 0-40 please state as the oilman thinks it's fine. By almeans take his advise and keep it in, but start savin for a 2k rebuild.

Sure Guy :)

But whilst there seemed to be some conjecture at the time re the "0" Winter weight, I was just 'looking out' for the poster, by 'playing safe', that's all. ;)


That said though, is 0W still okay for Tizer's early MY93-96 heads' hydraulic lifters? i.e. will they still pump up okay?

stick with 10w 40 .i ran 5w 30 mobil one in my car as told to do by pages and gave it some stick and killed all the bearings in the engine on 10 mins of hardish driving

I used to use millers 10w 60 until i found SN, from other peeps experence the 60 seems to thick, imo i think on a long blast on a hot day the 40 maybe too thin , so i use silkolene 10w 50 pro s as a compromise.

Ive just bought some Miller 10/60 for mine. Now i dont know whether to put it in? lol

Any ideas? it a modded 02sti about 350 or a little more bhp

Yeah, I'd say a 10W-50 is the best compromise too. :)

i was using 10-40 in last impreza was going to do same in this and use Rock oil any thoughts on Rock oil products please before i do

Not really, no smoke either but emissions are just creeping over what is allowed. Compression is down 40% on cyliners one and 15% on 3. Apparently pressure is going past the rings.

At an oil change would half 10-40 Millers CFS for example and half 10-50 Millers CFS make a perfect 10-45?

I found this stuff to be great :thumb: and the best about it , its cheap as CHIPS :lol1:
http://img.alibaba.com/photo/1102471...ooking_Oil.jpg

lol

Very good.

Wouldnt put 0W in my lawnmower let alone the scooby.

Millers 10/60 or Motul 15/50

Yeah, it would.

Give it a go and see how you get on.

Cheers

Guy