Is fuel economy improved by switching to lighter engine oil?

[blacknight]

Would switching from 10w/40 semi synthetic oil to 5w/50 fully synthetic oil be more economical? when i say 'economical' meaning more miles per gallon. The cost of say a Magnatec vs Mobil 1 is not the issue, just wondering if there would be any difference in switching to a lighter oil? The Magnatec which i used needs to be changed about once in 8 months but i noticed that it would be 'coffee-brown' in color without any burning smell or taste. going fully synthetic in the Mobil 1, would stretch the oil change interval to 12 months or 8000km whichever comes first.

The car I'm thinking of using it has no leaks or noises and has 200000km+ on the odometer. Can i have some opinions?

[Burnout124]

in my vy v6 i have run 10w30 and 20w50 i found no difference . but try it for your self just dont expect a big improvement.

[ParkwayDrv]

You taste your oil?? o.O

[MikeCuzzy]

Nothing that you'll notice.

*Driving style.
*Type of driving.
*Tyres.

All come well before choice in oil.
If your oil is still fine after 8 months, and you think you can get away with 12 months or 8,000km. You're not exactly flogging your car around town or on the freeways, so long as you use a decentish oil and fill up with good petrol, you're effectively running your car at optimal level.

[edals]

No DIfference mate. I went from 10-140 to 15-60 as my cars are getting on in KMs and it gets extremely hot hear in summer and found no difference, besides a smoother & quieter engine

[Jarrad]

You taste your oil?? o.O

Thats what I thought when I read that!!!

[Full Spectrum]

I'm using full synthetic 10/50. first oil was 20/50. no change in economy. honestly not much will change economy more than .1.

[TonyJZX]

has anyone ever moved to a thinner oil and found the engine revs quicker?

i havent owned mine long enough to see

[blacknight]

Yes, i taste the oil if it smells burnt when i sniff it. it might sound weird and flirting with carcinogens but imo, if the oil smells burnt its at the end of its life. I have switched from Magnatec 10w/40 semi-synthetic to Mobil 1 5w/50. I did a full engine flush, changed the oil / fuel / air filter / plugs just like when i serviced it with the Magnatec. I have noticed three immediate things upon a cold start up. There isnt a 'tappity-tappity' sound coming from the engine, the engine is more rev happy now and there's less smoke. Its too soon to compare the economy behind the two since I am only just ran a quarter tank of fuel through normal journey to and from work.

By the end of the week, I will want to check the colour of the oil.

[blacknight]

Yes, i taste the oil if it smells burnt when i sniff it. it might sound weird and flirting with carcinogens but imo, if the oil smells burnt its at the end of its life. I have switched from Magnatec 10w/40 semi-synthetic to Mobil 1 5w/50. I did a full engine flush, changed the oil / fuel / air filter / plugs just like when i serviced it with the Magnatec. I have noticed three immediate things upon a cold start up. There isnt a 'tappity-tappity' sound coming from the engine, the engine is more rev happy now and there's less smoke. Its too soon to compare the economy behind the two since I am only just ran a quarter tank of fuel through normal journey to and from work.

By the end of the week, I will want to check the colour of the oil.

[pjdm1980]

WTF!!!!!

Yes, i taste the oil if it smells burnt when i sniff it. it might sound weird and flirting with carcinogensl.

It doesn't sound weird, that is weird!

[wraith]

Reminds me of that ad of the guy swilling oil like it's wine.

[GRPABT1]

It can increase economy but as mentioned it's such a small margin you'd be better off adjusting your driving style.