my99 oil change...what oil?

[coco_scooby]

hi

gonna do a oil change myself...

i have a my99 scooby turbo with 80k on the clock...

what is the best oil???

thanks

[Oilman]

Stick with an sae 50 tops.

Either 10w-50 or 15w-50. 10w-50 will give better cold start protection.

Cheers

Simon

[paddy247]

Millers 10w/60 fs or Millers10w/40ss

[Oilman]

Look for an sae 50. Either 10w-50 or 15w-50.

Cheers

Simon

[paddy247]

Millers 10w/60fs or Millers10w/40ss

[paddy247]

Oil man what type of scooby do you have/run?

[Oilman]

I don't, I run something different but Japanese of course.

Cheers

Simon

[paddy247]

I run a classic wrx sti, and 10w/60 is like it was made for it

[Oilman]

How does that work when there is no mention of sae 60 in the handbook or recommendations.

Cheers

Simon

[teknopete]

Coco,

How u doin bud ? Its me fella, despite visious rumours i havent fallen off the planet

For normal running I use comma synergy, it`s good stuff and it comes in 5 litre packs from memory 5w/ 40

fFr track days I normally run Castrol RS (not the motorsport one though as I found it to thin and makes the engine noisy)

Hope this helps ya bud

BTW has anybody noticed how small the new oil filters are in comparison to last year and the year before`s ?

I`d say they`ve halfed in size in the past 2 years, which is good as it takes less oil to fill but i`d imagine it`ll clog

a lot quiker and heat up a lot quicker as well.

Pete

[paddy247]

Oil man/simon

I take it by s.a.e you mean Society of Automotive Engineers, the guys/gals who classifie motor oils according to certain viscosities and general tempature ranges.

10w/60 provides exellent engine protection under performance driving conditions and also has a low viscous drag, this ensures superb cold start and rapid circulation in cold temperatures.

Its also race proven for high temperature protection.

Its also good for niping down to tesco at a steady pace.

[Oilman]

That sounds awfully like the Castrol Marketing blurb.

It's your car mate, use what you want

Cheers

Simon

[paddy247]

Cant remember, had it written down from a google search ages ago lol.

anyway, i know for a fact that a lot of specalist mechanics with a lot of experience on the impreza recomend it, i can also tell you that there is a lot of impreza owners with this oil in there car and have had great results from it, And a few specalist workshops that i know of use it,

I personally run and maintane my own car, and have had great results from 10w/60

Im not looking for an argument here but if you have no engineering background and dont own/run an impreza, then your opinon will be based on slighty different knowledge than my own.

cheer up its nearly summer lol

[coco_scooby]

hello pete...

nice to see your back...!!!!

yep very small filters..i was shock when i got mines....

so Castrol RS is ok????

thanks for all the info guys.... (y)

[Oilman]

I'm not looking for an argument either, just trying to help.

My speciality is oil and not only is this my profession but I use proprietory databases (subcription only) to research the best oils for all types of cars from vintage right up to date.

I can tell you that regardless of your results, this oil is not the best grade for your car. Quite simply it's too thick.

There are reasons why thick oils are not good for your car but the most important one is wear caused by heat which is caused by friction due to the oil being too thick. Added to this, dragging an oil around your engine that is too thick causes a reduction in BHP at the wheels.

So, why is this oil too thick?

Well, the important thing is, at what (sump) temperature is the oil at a viscosity that suits a modern high-RPM engine.

Present day designs are more than happy on an oil viscosity of 10 to 15 cSt. (But many are OK on less than 10.) 30cSt is too high at high RPM. It can lead to foaming, air entrainment and cavitation.

............Temp. for 30cSt (Deg. C).......Temp. for 15cSt.......Temp. for 10cSt

5W/40..................71...........................90........................117...............

10W/40................70...........................99........................118...............

10W/50................80...........................109.......................130..............

10W/60................89...........................119.......................142..............

This shows that for example a 10W/40 is perfectly adequate for all engines except those that run an unusually high temperatures.

What you also need to consider is at 100degC oil temperature an sae 40 is 14cst, an sae 50 is 18.5cst and an sae 60 is 24cst, these may not seem big differences but calculated as percentages, they are.

I hope that these figures at least give some insight to what actually happens to the oil inside your engine at different temperatures.

Finally, do I recommend 10w-60? Yes I do where warranted but there are few cases in which it is actually necessary and these are mainly based on extreme oil temperatures and by this I mean in excess of 140degC for prolonged periods.

You see, owning a Subaru and not being an engineer actually has nothing to do with recommending the correct oil when it's your profession

Cheers

Simon

[teknopete]

Simon,

Good info there m8, very similar to the info I received many moons back when I was researching oils for general use & trackdays.

Kinda confirms i`m running the right gear. Most folks have personal preferences as to manufacturers i.e. Mobil, Castrol, Valvoline etc,

but there`s the facts for all to see.

Cheers Simon it`s good 2 hear from peebs in the know.

Pete

[paddy247]

I still disagre with you, 10w/60 is not to thick,

However these are my own results and findings,

simon since you are good at sourcing information, can you tell me what the ideal flow in centistokes is at ideal oil operating temp for a subaru impreza?

cheers paddy

[Oilman]

Paddy,

It varies depending on year.

Pre 2000 it's around 14-18cst and post 2000 its 10-14cst.

Cheers

Simon

[dave_morgan]

I have to say, I'm with oilman on this one. Why go for a thicker oil if you're getting the protection you need from a thinner one ? You're just working your oil pump harder to get it pumped around and creating more friction for no benefit. Unless you're regularly running at high temps, it seems a bit pointless to me too.

Everyone is welcome to their opinion however. Personally I run Motul 15/50. If it's good enough for STi, it'll do me !! (if I was in the highlands, I would probably drop to a 10/50 or 5/50).

Dave

[paddy247]

cheers simon