Combat

Hello all,

Well, looking through the documentation for the Impreza, it would seem an oil and filter change is a little overdue. I've sourced a genuine Subaru filter from ebay, so that's that covered.

Now, I did a little bit of searching on here, and what I found was the biggest thread o' arguments and disagreements ever where oil spec was concerned!

After reading through the owner's manual, it would seem aparrent that between -20'F to around 38'F the oil spec is 5W30, and for just under 0 to over 100'F the spec is 10w30 or 10w40 for the turbo models.
Even though my car has a full history file, the type of oil used is never stated.


I'm guessing then that I'd be ok to use a good quality 10w40 semi synthetic oil, the car just does a 10 mile commute in traffic every day and doesn't get used particularly hard, and is babied until it's up to operating temperature. I say not used hard, obviously the odd squirt now and then (I didn't buy it to tootle everywhere absolutely all of the time ) but it doesn't get much hard use.

I don't want to cause any upset or cause any ill feeling between members who may have differing opinions however!

The way I see it, as long as I'm not putting some cheap rubbish in, and sticking to regular oil changes, I can't really see any issues with using a 10w40 oil. Also, if Subaru state it's ok to use, then that's probably good enough for me. It doesn't hurt to ask the chaps and chapettes who run these cars on an enthusiasts forum though.

Cheers for reading!

Postman Pat

I'm gonna duck after I've written this.

I've got a MY99 turbo from new. During warranty period dealer put in 10w40 and I'm nearly sure it was Castrol Magnatec (memory is getting hazy). Since then I have done all the changes myself. I have been using Castrol Edge 10w60 (previously branded as Castrol RS) for a long time. I did try a thinner oil 5wsomething but it was far too thin and the tappets made an awful racket. The Castrol is sold as a fully synthetic oil and I have no problems with it. The car has done 130,000 miles now and is still going strong.

I am biased I know but I don't think you'll go wrong with the Edge. But I'm sure there are hundreds of different opinions out there.

Pat

his-n-her-scoobs

iTrader: (5)

Hi Combat,

Have to say that I agree with you.

Both our unmodified UK MY97 cars are used as daily drivers, rain or shine. Driven hard enough to warrant 4 pots but no track use.

We use Vauxhaul or Quantum 10w40 semi API SL/CF on the grounds that
a) Spec approved by Subaru for STANDARD engine in AVERAGE use
b) Vauxhall or VAG won't risk their reputations by buying rubbish
c) It's cheap because the above companies have bulk buying power
d) Oil is changed every 5000 miles

That said wife's big ends went at 130,000 miles but on a car we bought cheap as it had little history up to 100,000 miles (and what had been done I had to redo)

Mine gets driven harder and has 130,000 miles with good history. Suffers from the usual piston slap but is all at the moment. Have a spare block in the garage waiting for when it does let go

eggy790

iTrader: (20)

Motul 300V Power 5W-40 Racing lubricant for racing cars

i think this is the oil everyone recommends on here.. bit pricey to say the least, maybe a bit too good for your needs though since you dont do no trackdays?

nampahc01

well rcm told me to use 15w50 in my 97wrx import but mine is a 2.5

they use silkolene 15w50 pro race £60

i've used mobil 1 15w50 race stuff £50

but everyones opinion is different as you can see. older engines i would be more inclind for the 15w 50. saves burning the thinner 10w. my opinion though

Combat

Many thanks foryour replies so far guys, that's to all of you!

After looking up things on the 'net, it's become even more aparrent that there's much differing of opinions there too! Mine most likely won't be doing trackdays, so that's such an issue I guess.

I've read from a chap called 'Oilman' (on a few different forums, may have seen him post here too?) that a 5w40 oil is about right for the job, unless it's used on track, though I assume for more sustained trackwork as in a dedicated track car rather than a few blast around laps.

Here tis:

Oil Advice and Recommendation - Page 3 - PassionFord

Oil Recommendations here! - Subaru Impreza Forum - WRX STI Rally Performance Tuning


While some say a 5w is fine, there are some other votes for 15w, but also a few saying that's a bit heavy, especially for cold weather use (cold flow rate anyway) and a lot agreeing a 10w is best. I had no idea choosing oil would be such a mind bender!!


I also found these:

5/40 5w40 Synthetic Motor Engine Oil 5 litre Bottle on eBay, also Other Car Care, Car Care, Car Accessories, Cars, Parts Vehicles (end time 24-Dec-08 13:40:46 GMT)

SHELL HELIX ULTRA 5W40 ENGINE OIL (5 LITRE) on eBay, also, Mitsubishi, Car Parts, Cars, Parts Vehicles (end time 21-Dec-08 15:04:45 GMT)

Someone also suggested I could use Valvoline VR1 5w50 fully synth, gah, the choice! I'm guessing that may be a little too thick at operating temp though.

From what I can tell, (I'm a novice on this subject!) the lower *W number is a cold flow measurement and the high number the same flow measurement but at operating temp, if I've got that mixed up though, please tell me won't you!

I'm off to bed I now I think, as my head's hurting!

Combat

Head hurt or not, it didn't stop me looking!

And getting more confused!

5w-40? - Page 2 - NASIOC

Effects of Shearing

So, aparrently, an oil with a higher numerical spread, say the 5W50 will have more viscosity improvers and be prone to breaking down more easily than say, a 10W50 or 5W40 (massages scalp).

Also found this on here:

HALFORDS TRACK DAY OIL?! WRX OIL?!

I really am going to bed now!

prwatts

Last word: Listen to Oilman. Motul or Silkolene have ester oil bases. I was always a Shell man - worked for 'em 25 years ago - and Shell's oils are good but even Helix Ultra, like most of the other oils mentioned above except Motul, have a mineral base. I hear talk of Millers but don't know about them. Pure ester based oils are more stable. But if you drive normally they are ok. 5WXX is fine for journeys less than 10 miles. I have oil Press & Temp gauges and I have watched what the oil does. You want 'thinner' oils when cold to get around your engine quickly. 15W50 for journeys of less than 10 miles is not optimal (and wastes fuel) When you have high Blood Pressure you take Warfarin to thin your blood out so it gets through your veins more easily. All the oil does, like blood, is carry the additives around that do the job. 5W40 fully synthetic, (not part synthetic) or better still fully ester based oil. BTW Castrol is owned by BP so they blend to a cost. No free lunches, heh heh. My feeling is why risk a £2000 rebuild on £20'th of oil. Don't undestand that logic. Peter

eggy790

iTrader: (20)

prwatts could you clarify what you said about the oils and journey times 5w fine for shorter journeys?
15w not? better for longer journeys?

or have i misunderstood?

can you get a 10w 40 motul 300v? that seems to be the middle of what everyone seems to say?