Doublebase

Well I'm now 3,000 miles into a 5w30 weight synthetic oil change. I have not lost a drop of oil yet, but I really wasn't expecting much anyway. My gas mileage has improved - compared to the first three weeks into the oil change - I'm now back to averaging 26.2 mpg. And I swear to you that I couldn't achieve that mileage during the initial part of going to 5w30...might the oil have sheared just a little bit?

I'll check back in when I reach 5,000 miles.

One thing I'll probably do if this proves successful, is go to a higher quality brand of oil. Right now I'm using a Napa house brand full synthetic and it's basically rebadged Valvoline, which is very light on additives...virtually no moly.

roadfrog

Nice. That's good news.

superdenso

The 5w30 gets better with time. I almost pulled my 0w30 at about 2,500, but it holds up pretty well too. The 5w30 has given me better results (i.e. no "mystery" oil loss and more mpg's)

Doublebase

Well that didn't work, I've reached 5,000 miles and I ended up adding a quart between 4,000-5,000 miles. So much for the 5w30 being thicker, shearing less and consuming less...it didn't make a single difference.

Maybe it was because I used a cheap house brand synthetic that had very little additives? I don't know? And really it's not something I'm worried about, using a quart of oil in 5,000 miles is not exactly something to get depressed about - if this was a BMW or an Audi, it would have used 5 quarts.

I just bought a bunch of Mobil 1 (it was on sale and with their rebate program they have going on right now I ended up paying $2 a quart). So that will be going in the car next. Mobil 1 has a pretty robust additive pack with a good amount of moly and boron (both of which was missing from the last product I used). Maybe that will help? I guess I really do mind either way, the car runs great and I certainly can live with a loss of a quart in 5,000 miles.

I'm going to stick with the heavier weight oil for a while anyway...my gas mileage stayed consistent with what I got when I was using the 0w20...plus the weather is getting warmer around here now.

roadfrog

Thanks for the update pal. I'll be switching over to Castrol 5W30 next week. We'll see if it makes a difference, but I don't really care if it doesn't....it's more of an experiment than anything else. Like you, I'm very OK with a qt every 5k miles.

Doublebase

No problem and like you I really don't think anything of using a quart in 5,000 miles, especially from a car that now has 126,000 miles on it. And like I said, I wonder if I had been using a better oil things could have been different? Let me know how it works out for you with the Castrol.

lextout

with the 1/2/3uz motors, you can go to 10k intervals with synthetic, and you wont burn a drop and the oil will still look good, an oil analysis was done and proved right.

Doublebase

Yeah I always liked the smoothness of those engines, but I don't recall going 10k miles on oil changes anywhere near the norm of what people did with those engines. People that drove around with the 1 and 2 uz's probably never even considered going that far back then, it was unheard of/blasphemy. CAFE regulations changed the OCI in the industry. I see a few people with the 3uz extending their oil changes out that far, but not a ton.

roadfrog

I've had several oil analysis' done on my oils - one of them at 10k miles, and they always returned with a clean bill of health. That said, the oil is going somewhere.....and it's not leaking.

litesoarer

I think 7,500 miles is a healthy compromise for a 95% highway car.

roadfrog

Yep. I'm doing 7-8k miles on my changes from here on.

Wandl

So the 4.6L V8 engine is like a common household dryer, eats up socks mysteriously every now and then?

roadfrog

It's not a mystery. EVERYONE knows that the socks go into a time travel due to the speed of the spin cycle. Sheesh.

roadfrog

Oh...and I added another qt today. So that's two qts in 6k miles so far.

Doublebase

Yeah once I start using a higher quality oil, that's the number I usually shoot for. I'm no longer concerned with losing a quart of oil along the way...my experiment with a shorter oil change interval and heavier weight oil didn't really change much. I feel pretty comfortable going 7,500 with a quality synthetic.