advice on oil change

hey guys 

i have been having fuel efficiency issues with my new fluidic verna petrol and no issues could be found. so based on the warranty guy and my own self i wish to change the oil. the warranty guy says i can get my own oil if i want or use their mineral oil 15w40 api-sg i guess

based on my user manual recommended oil for better fuel economy which suits my ambient temperatures is 5w20/5w30 api-sm ilsac gf-4 and above.

guys recommend me a good fully synthetic oil which meets my requirements and is available in mumbai thanks

guys some help please?

Does not matter what oil you change to - the act of changing oil will itself improve mileage. The reason being that in a new engine there are a lot more ground off metallic particles due to tight tolerance - this causes greater friction and hence lower mileage. Once you remove all the old oil and oil filter, all this dirt gets removed to resulting in en engine with parts better seated and smoother resulting in better mileage.

As for oil grade anything from 10W40 (synthetic), 15W40, 20W40, 20W50 can be used.

thank you for your reply rohit. i have done a bit more research and found out in usa for my car they use 5w20 grade oil even in texas and california a few guys used xW40 grade and found that their mileage dropped.

should i go in for 5w30 since i know honda civics and maruti ritz and sx4 uses the same grade? 

The number before the "W" is the viscosity when cold, so lower this number the thinner the oil is - it means that the oil will have the same viscosity at 5 deg F as an oil which is at 30 deg F temperature. If you use 20W50 (or 20W40) when the ambient (or cold engine) temperature is zero deg F the oil will be much thicker and hence cause pistons to have less lubrication during the period the oil comes up to operating temparature - this period will be longer in this case. This means more friction and hence greater fuel consumption till the oil gets thin enough to lubricate properly.

Therefore the oil used should be rated according to the coldest temperature expected during start-up. For Mumbai conditions almost any oil will do from 5W30 to 20W50. Since the engine is new 5Wxx or 10Wxx oil can be used - but I'd not recommend this for older cars since the oils are rather thin and can dissolve any "good" dirt - this is dirt that is basically formed at the correct place and acts as a seal - where the actual seals may be worn out and the "dirt seal" offers additional protection. If this gets washed out, the original seal may not be upto the job and the result will be a rather expensive engine job!

Hi Rohit,

so for old cars what do you say.. which grade oil.. should it be 15W40???

can you suggest for a petrol accent which has done 82k kms (2001 model)??

i was planning to use shell in this grade!!!

Well, I guess 15W40 can be used - but the regular multigrade 20W40 or 20W50 will work as well...and probably would be better. It all depends on the engine's condition - that warning about "good dirt" is a sort of safety net because we simply cannot predict what is inside the engine till it shows itself...which is mostly never pleasant.

Dear Rohit,

Since you also own a santro, kindly suggest a decent engine oil for my Santro Zip plus 1.1 ( 2003) covered 35000 kms till date. IF possible would like to know the approx cost for a complete oil change.

Regards
Rahul

thanks again rohit. the car is a new verna. i had a word with hyundai customer care a while back. they say due to tighter tolerances using a thinner oil which is low on ash, like energy conserving ones preferably synthetic or semi synthetic will provide an increase in fuel efficiency, using thicker oils will give better lubrication but at the cost of fuel economy. 5w20 nd 5w30 is approved for the entire temperature range.

can you tell me what should be the cost per litre of synthetic oils like mobil1 or shell helix ultra extra? 

Not sure but expect upwards of Rs. 900 for a 3 litre can.