Thicker vs thinner oil for short journeys?

reddwarf2002

This is a hypothetical question: if someone was to do very short journeys in their car meaning the car rarely got upto operating temperature then would a thicker or thinner engine oil be better for the car? For example 5w30 vs 5w40 assuming both were compatible for the car.

reeac

reddwarf2002 wrote: »

This is a hypothetical question: if someone was to do very short journeys in their car meaning the car rarely got upto operating temperature then would a thicker or thinner engine oil be better for the car? For example 5w30 vs 5w40 assuming both were compatible for the car.

Thinner so that the oil got circulating around the engine sooner in order to minimise cold-start wear.

vaio

but I suspect any change is going to be marginal at best

I'm pretty sure it's the first figure that indicates cold performance so if you wanted thinner when cold you'd need 0W40 rather than 5W40 (think the W stands for winter?)

Trebor16

vaio wrote: »

but I suspect any change is going to be marginal at best

I'm pretty sure it's the first figure that indicates cold performance so if you wanted thinner when cold you'd need 0W40 rather than 5W40 (think the W stands for winter?)

The W does mean winter. This link here gives a good explanation of viscosity:-

http://www.opieoils.co.uk/pdfs/tech-articles/Engine-Oil-Viscosity.pdf

vaio

Yep, back in the old days 20/50 was as thin as 20 grade oil when cold and as thick as 50 grade when hot

bigjl

If you head over to Bobistheoilguy you will find plenty of information that will help to answer your question.

Most engines will happily run on a range of oils dependant on the temperature they are operating in.

We have moved house a few months ago and now the wife does only urban miles usually under 5 miles. When previously it would be twice that with most on A roads.

The car has had mostly 0w40 in it with some 5w40 and once 10w40.

As the car now doesn't get fully warm i have been considering running it on 5w30 this winter.

The only thing in my case is that the later versions with a dpf use 5w30 so the engine should be fine with the oil which is slightly thinner when up to temp

Some on Bobistheoilguy run oil as thin as 5w20 and one runs 0w10 i seem to remember and has had no issues noted after used oil analysis.

The important thing would be an oil pressure guage.

As that is the thing to be worried about.

Stoke

If you're only doing short journeys, I always suggest 0w40 in the summer and 0w30 in the winter.

If you do longer journeys, such as commuting to work, I suggest 5w40 in the summer and either 5w30 in the winter or 5w40 in the winter. The reason I suggest that is because 0w40 is quite runny and I found it can burn a bit quick.

That said, the differences are marginal, and your car manufacturers don't recommend oil for nothing. Personally, I think a more important choice is switching from semi to fully synthetic oil. The benefits of fully synthetic oil are for everyone, and they will make your engine last longer. Switching isn't exactly harder either, it's just a case of finding the right oil and performing an oil flush using something like Forte Flush, just to get any old oil out.

Strider590

It aint the oil you need worry about with short journey's.........

Someone please explain