The tag in the engine compartment of my wife's 91 accord recommends 5w-30. I have been using 10w-30. She averages 24-30 mixed (mainly city) driving. I have heard that switching to the 5w-30 will result in improved mpg. Is there truth to that? Thanks.

 

Yes there is some truth to that. But i don not think it does that much difference.

fs

 

Yes, but maybe only a mile or two per gallon

 

Yes it makes a difference. It will change it more closely to about 2-3 miles per gallon. If the engine is in good shape and seals are not leaking you can use there 5W20 with no problem and you will see about a 5-6 mile per gallon incresse. Just watch the oil leave for the first 1k miles or so if switching to 5W20, some engines will develop leaks because of the thiner oil and use a little more. If ther is no sings of this then by all means keep using it. But if its used say 1.5qt's then I would switch back to a little thicker oil like the 5W30.

 

The so called "experts" nowdays recommend thinner oils and the 5w30 is just that. Less friction=more efficency=better mileage. I doubt the difference would be much but a mile or two more a gallon is alot nowdays. Switching to fully synthetic oil will help you even more... I've never run anything but 5w30 in my Accord

 

How much of a diff. in lubrication/temperature qualities we looking at between 5w-30 and 5w-20? I wouldn't mind pushing 40 mpg on the highway with a 14 hour drive to go back home from Christmas!!! I have absolutely no oil leaks right now with better than stock compression, I'm not opposed to the idea but I do a lot of cold starts and push her hard. I will never trade in my sawzawed intake, ghetto and cheap as hell but she runs like a charm!