In the states we use 5w30 for everyday use and 10w30 for track days, why the extreme weight oil reccomendations in the UK? I can think of no benefits from running thick oil, only negatives like horsepower loss from drag on the bearings, hotter bearings from the slower flow rate of heavier oil and increased fuel consumption. I can understand using higher viscosity oils in warmer climates...like maybe brunei or brazil or some desert area...or on high milage engines or in high horsepower engines.

Heres another question, what does Subaru reccomend for oil in STi7/8's in the UK.

Thanks in advance folks, just trying to expand my global subaru knowledge

 

I agree - my mate in LA runs these thin oils and it scared the sh!te out of me !

T.

 

The subaru handbook that came with my car says that 5w30 is not suitable for turbo models or for continuous high speed running or something like.. and suggests heaver weights up to 20w50 for hard use or high ambient temperatures..
dunno what they recommend for latest ones mind..

Isn't the thin oil thing mainly to comply with the cold start emissions etc? never noticed any measurable difference between the "thick and thin" oils at operating temperature thou.

 

Subaru of America reccomends 5w30 and only 5w30 for the wrx

 

I was 'advised' anywhere between 5W30 (Subaru service) for my STI to 15W50 (Performance tuning shop who assures me he done too many rebuilds on WRXs running 5/10W30). I settled for 10W40 to suit the climate (average temperate around 25C) and driving style (spirited)

Probably should go for the 15W50 to be safe.. hope the Motul works well!

 

5w30 is advisable for temperatures below zero, running above that it states in the subaru handbook that you may not get the maximum lubrication for the engine (and this is from subaru itself!)
I would not run 5w30 again in my scoob as it sounded like a bag of nails when i did so originally.

Tony (runs 15w50 oil now and the official oil from STi is also a 15w50 oil )

 

Interesting! The 5w30 reccomendation by SOA isnt based on temperature, its the same for 110f to below freezing. I've never put anything but 5w30 in my wrx and it purrs like a kitten year round.

 

I run 5w-40 in winter to cover skiing (as low -20C) and the quick sprints to get there and back, but considering going to 5-50 coz the 5w-40 picks up some horrid smells and discoloration after only 3000kms (must have something to do with the 3hrs+ "sprints" @ "tollway" speeds ).

In spring/summer/autumn I run 10w-50 - does well on track and in town.

The Japanese dealer 5w-30 was e x t r e m e l y dodgy after 3000kms

 

don't quite understand the hotter climates recomending oils specced for "cold" use........we use 15w50 or 10w60 for all of our road and competition cars - 10w60 particuarly to deal with the extra heat generated by competing !!
alyn - as performance

 

Turbocharged motors need thicker oil- the oil runs a fair shade hotter because the turbo sits there warming it up all the time.

 

Well i think that SOA need to check their handbooks rather than go off the top of their heads
The handbook for my classic MY00 turbo (same turbo engine as the WRX MY01 onwards) states that turbo models should use either a 10w30 or 10w40 for temps above -20, and below 0 a 5w30 can be used.
Now it also states for NON turbo cars that a 5w30 oil is preferred thoughout the range or as with the turbo model 10w30 and 10w40 from -20 upwards.
Also noted in the handbook (section 10-12) the BIG CAUTION sign stating the following.

:- Use only engine oil with the recommended grade and viscosity.
:- As for the turbo models, SAE 5W30 is NOT recommended for sustained high speed driving.

I think that says it all

Tony