Interesting oil observation

[JimGnitecki]

I bought my Z06 new in May. It came from the factory with Mobil 1 oil of course.

At 1000 miles, I had the oil changed, and had them use Royal Purple brand synthetic.

I check the oil in my car about every second gas fillup, just because that's my habit oveer the past three decades or so. On the Z06, it's hard for me to read the level on the tick, as the oil stays so clean, and my eyesight at 52 is not great for detail to begin with. So, what I look for is to make certain that the lower hole in the dipstick (the one labeled "add") still has an oil bubble in it (the top one never does unles you do the check after the car has sat overnight and all the oil has returned to the sump, and it's viscous enough to stick to the dipstick better). With the Royal Purple in there, the bottom hole ALWAYS showed oil in it.

When I next changed the oil at 4500 miles, I had the shop put in Mobil 1 again, instead of the Royal Purple, as I wanted to see if there were any apparent differences in consumption, oil temp, etc.

The car now has 7000 miles on it, and when I checked the oil yesterday at a fillup, for the first time I didn't have oil in the lower dipstick hole. I had a spare 1/2 quart of Mobil 1, so I added it.

Note that I had put 3500 miles on the Royal Purple, with no detectable oil consumption (4500 odometer miles minus 1000). After I changed back to Mobil 1, I had detectable usage after only 2500 miles.

This morning, I checked what the reading on the dipstick is after the car sat overnight. It's still below the "full" mark, even though I added the 1/2 quart yesterday, so the usage was evidenty more than the 1/2 quart I added.

The car's usage has remained VERY consistent during the entire 7000 miles, and definitely on the "easy" side (I average 21 mpg on all my fillups, and my absolute worst fillup, mostly subrban traffic and stop & go, still showed 17 mpg). A large majority of my driving is the 200x2=400 mile per week commute between my home in Austin and my weekday work assignment in Dallas.

This is FAR from a controlled oil consumption experiment. But, it IS enough to make me want to study this further. I think I'll try the Royal Purple again next oil change, and see if the consumption returns to undetectable.

One difference that I THINK might be relevant is that the bottom of the viscosity range for the Royal Purple was 10W, whereas the only version of Mobil 1 available (at least at that shop that day) was the one with the 5W bottom end. I realize that GM and most manufactuers recommend the 5W, but that's NOT for engine protection, but rather for slightly (VERY slightly) better fuel economy. IN the 95 to 100 degree summer daily temperatures around here in Texas, I think the 10W is a better idea.

Jim G

[aprsr]

Not really a technical answer; but the Corvette mechaninc at the local Chevy dealer said they put 5w30 in the engines because they may be going to a colder climate area, he recommended going to 10w30 at the first oil change.....

[ZO6LS6]

Jim,
RP is available in 5w/30w......
I use it.......

[McRat]

I've always had more consumption with Mobil than other brands on LS1/LS6's.

I currently run Syntec 10-30 which has little if any consumption.

[ruking1]

Just as long as whatever synthetic oil you prefer meets the GM 4178M specification!

I personally have stayed with the Mobil One, but many folks on this forum have good results with Amsoil and Redline. I have many miles in other cars with Mobil One so I am at comfort using it in the Vette and doing up to 15k oil and filter intervals. I use Mobil One for a number of reasons: 1. it is recommended by Corvette 2. it is commonly available 3. it goes on sale 4. I have in excess of 600k miles validating that this is good stuff and with 15k oil change intervals. My goal is 175k miles and beyond on the Vette, so this is an extremely important issue, with bang for the buck in behind.

If you feel that Redline and Amsoil are worth 2-3 times the price of Mobil One on sale, or can get either product line for the price of Mobil One or less, then by all means... go for it!!

[RocketSled]

Originally posted by JimGnitecki
On the Z06, it's hard for me to read the level on the tick, as the oil stays so clean, and my eyesight at 52 is not great for detail to begin with.

I "roughed up" the dipstick with a little 400x sandpaper and now the oil sticks to it much better. Definitly improved my ability to read oil level.