What oil for short journey's?

[bonesX]

Following on from my thread yesterday on 'How short a regular journey is bad for your engine?' http://www.pistonheads.com/gassing/topic.asp?h=0&a... I was wondering if any mitigation could be achieved with oil selection?

My commute is 4.5 miles rural lanes

I was thinking maybe something like Millers 10w40 fully synthetic, as it will be at it's best a lot sooner than a say 10w60 (very thick oil) and give better flow around the engine, or a 5w40, if going for an oil for summer then even a 15w50 like Motul 300v would maybe suit...?

(V3 STi Scooby, ~100K miles)

Thanks for all the comments

[trickywoo]

bonesX said:

Following on from my thread yesterday on 'How short a regular journey is bad for your engine?' http://www.pistonheads.com/gassing/topic.asp?h=0&a... I was wondering if any mitigation could be achieved with oil selection?

My commute is 4.5 miles rural lanes

I was thinking maybe something like Millers 10w40 fully synthetic, as it will be at it's best a lot sooner than a say 10w60 (very thick oil) and give better flow around the engine, or a 5w40, if going for an oil for summer then even a 15w50 like Motul 300v would maybe suit...?

(V3 STi Scooby, ~100K miles)

Thanks for all the comments

As I understand it the first number is a measure of viscosity (how 'thin' it is when cold) the second number is how well it resists breaking down at high temperatures. So lower first number and higher second number is good.

However, if I were you I'd stick 10w40 of a good brand in and change it every six months. Very inportant on an Impreza to make sure a new oil filter is fully primed before you fire the engine BTW.

[steveo3002]

anything thats the correct spec , and change it more often

[R12HCO]

5-40w

[Mr2Mike]

steveo3002 said:

anything thats the correct spec , and change it more often

This. Whatever oil you use is going to get contaminated quickly with shorty journeys.

Ideally walk, cycle or even get a scooter.

[CampDavid]

R12HCO said:

5-40w

That would have been my answer. Or walk 4 and a half miles everywhere

[dylan0451]

i used to get a slight rattle on startup using a 10w 50 in my old mx5. as we went into winter i swapped to mobil 1's 0w 40 and it went away. as stated above you want the lowest W or winter number as this is the measurement of an oils resistance to flow at 0c. the higher number is the oils resistance to flow (both measured in cst or centistokes) at 100c

all oils regardless of spec are always thicker when cold, so don't believe any twoddle about '0w oils will make your engine leak'

unless your engine's already leaking like a sieve, then it goes withouut saying it's not going to stop

[Parrot of Doom]

4.5 mile rural commute? Use a bicycle, it'll take 20 minutes to do that distance and cost you nothing in fuel. Then you can have a nice car for the weekend.

[bonesX]

Thanks for the replies. I would use a bike but have manky legs from an old car accident

5w 50 seems the way to go and change more often

[dylan0451]

bonesX said:

5w 50 seems the way to go and change more often

what's the recommended oil spec for your impreza? if it's something like 10w 40 i wouldn't bother with a 50, unless you track the car/it's heavily tuned and are having overheating/oil pressure loss problems

[bonesX]

Sorry, meant 40