So I have a 04 Acura TL & given it my 2nd ever oil change & it reached the 100k miles so Autozone recommended me to use Mobil 1 10w-30 syntetic oil rather than the dealer 5w-20 I live in LA CA , should I be concerned or should I change it back right away? As I have noticed the MPG drastically reduced so far :/ ?? Help !!!

 

Your MPG should not be impacted that much with such a change in oil viscosity. In order to make reasonable assessments of MPG you need to provide these details:

1. how you fill your gas tank- do you fill it up completely or only put $30 in or something like that
2. if you reset the mid every fillup
3. the MID's average speed calculation
4. the MID's calculated MPG

My money is on your commute changing, using the A/C more, or something other than the oil change.

 

dont listen to autozone employees any more.

 

I usually fill the tank but when I'm low on money half a tank so about 30. And I only put premium chevron or she'll to be specific , but I noticed the change the first day I changed the oil to 10w-30 .and i do not use the A/C

 

Mobil 1 10w-30 should not result in a 2 mpg difference in fuel economy.

So either a)your mpg really isn't going down that much (and you really need a full fillup to be able to tell) or

b) your driving habits have changed, no matter how much you say they haven't or

c) this is normal variance due to weather, amount of time in the car, duration of trips, etc

or

d) I think its coincidence. Something else might be happening with your car.

 

So my question is, is it's fine to leave 10w-30 oil till my next oil change? Or should I change ASAP to 5w-20?

 

10W-30 is perfectly fine to leave in long-term.

 

This. Definitely. This.

 

You should clarify in your MPG drastic reduction.

 

10w=30 is pretty common and standard for most vehicles and will probably be ok.

acura does specify 5w-20 i believe

i live in NE and winters can be brutal..... not sure if i have to change it up for me or if 5w-20 is good enough

 

10w-30 is not standard. maybe 10-15 years ago.

 

10w-30 is what the s2000 calls for year round protection and 5w-40 if you live in a cold area. As engines became more complicated and relied on more electronic stuff, thinner oil was spec'd as to the complexity of all the moving parts and such.

So like Vietx said, 10w-30 was more common back in the 70s, 80s and 90s, but I think 5w-10 is more common nowadays.

 

for "most" vehicles the standard is usually 5w-30, 5w-20 or even 0w-20.

That's what I see on oil caps all day at work.

Every now and than you'll get a Mercedes or BMW or any German for that matter that will call for 5w-40.

Gt500 Shelby cobra calls for 20w-50 lol

 

Another one of these threads? There is so much info out there on this subject, it's been best to death.

In the LA area I would run a 30wt over a 20wt any day. It's not only ok, it can be beneficial in reducing wear.

If you drive only very short trips and the oil never gets up to full temp the 20wt might be better. If you drive it more than 5 minutes on a trip, 30wt. Mine has seen 0w-20 when temps were near 0F and my drive was just a mile because even after a mile that 20wt is probably still a 60wt at that temp.

I ran straight 30wt when I lived in Vegas and Mesa and I now run Redline 5w-30 which is actually a straight 30wt. Out of the 126,000 miles on my car it's only had a 20wt for a total of 10,000 miles. It saw 40wt for 5,000 miles with no noticeable change.

Lowest engine wear is not the reason for thinner oil. Neither is "complexity". Going from a 20 to a 30wt in a car that does a lot of freeway miles results in an immeasurable change in mpg. In most tests, if you live in a cold climate and do mostly short trips, the change in weight can make up to .5mpg on the extreme end. This is a lot when you sell a million cars but not worth it to us, the consumer. I have enough inside info from some of the industry engineers that I won't run 20wt in my climate. I wouldn't worry if it were the only thing available but there's no reason to run it where I live.

You have to think about that 20wt in a cold climate. In a cooler area, say 60 ambient, that 20wt is going to be thicker at operating and at starting temp than a 30wt in 95F weather. If a 20wt is fine in cold areas, it makes sense that a 30wt HAS to be fine in the warmer areas.

To clarify, the bottom end has changed very little since the early '60s. If you take a look at a rebuild manual of something from the '60s and a TL you will see that clearances have not changed or tightened. Rod and main bearing clearance is still primarily a function of journal diameter. Ring gaps and piston to cylinder clearances are still a function of bore diameter, material, and expected usage. Oil weight has thinner down because of the government push for mpg and the newer better oils allow a lower viscosity with decent protection.

The biggest reason by far for engines lasting 300% longer today is electronic fuel injection. It's not tighter clearances. Today's oils help somewhat but they also don't have to deal with fuel dilution caused from carburetors. Oil choice is not a crucial today as it was yesterday thanks to fuel injection. A side effect of fuel injection is longer oil change intervals and secondary credit goes to today's modern oils.

Also, I don't know why people still suggest going thicker because the engine has 100k ok it. Back in the days of carburetors 100k was high mileage and there was at least significant ring and cylinder wear and the thicker oil could be beneficial. Any TL that's been taken care of is far from having any significant wear at 100k.

To end, a 30wt is more than fine for LA, it's beneficial, and it's not the cause of your mpg loss. On the flip side, unless you plan to pass 300k a 20wt will be just fine. Both will work fine. With either, the engine will probably outlast the car. In a regular climate for regular use, go with anywhere from a 0w-20 to a 5w-40.

 

I wouldn't venture too far from home. Your engine could blow at any moment!!

 

Only if he revs it past 2,000 rpm.