Engine Oil

[SnoEclipse]

The SM/SL spec change is pretty stupid. In a quest to reduce the small-but-not-zero possibility that zinc/phos *might* hurt cat converters, the EPA has set up a loop that will cause a LOT of owners to change their oil more frequently.

The main reason for oil changes is to renew the additive package, not to get dirty oil out of the system. Modern oils and filters are pretty good at suspending and capturing any nasties that actually get into engine oil.

Since the new 'smaller' additive packages don't last as long, people are going to generate 5 liters of 'used' oil 2-3 more times a year. And since synthetic oils more than doubled in price over the past year (M1 at WalMart went from $20 a gallon to around $40- a gallon), it will cost people another $120 a year in oil. Minimum.

Yah, since getting a set of cats changed at a dealership will cost over $1000- the SL/SM change might seem like a good decision. But the chances of a cat or O2 sensor being wrecked by an oil additive package is under 5% over the life of any car (assuming 150 k miles on the car) and way below 1% for the fleet.

With a decent PCV system (including catch can) and decent engine maintenace, an owner can take the likelyhood of this problem from damned small to extremely low/zero.

[Kracka]

Originally Posted by SnoEclipse

The SM/SL spec change is pretty stupid. In a quest to reduce the small-but-not-zero possibility that zinc/phos *might* hurt cat converters, the EPA has set up a loop that will cause a LOT of owners to change their oil more frequently.

The main reason for oil changes is to renew the additive package, not to get dirty oil out of the system. Modern oils and filters are pretty good at suspending and capturing any nasties that actually get into engine oil.

The above info is dead-on accurate; most people just don't understand this and are convinced black oil = bad

A 5 quart jug of Mobil 1 is $26 at Walmart though (bought some this morning). As a sidenote, a few weeks ago my friend had his 8k mile old Mobil 1 from his Evo IX analyzed by Blackstone and it came back with enough additive package still remaining to be effective (3.1 TBN; anything >1.0 is satisfactory for use).

[Matt D.]

Originally Posted by Kracka

As a sidenote, a few weeks ago my friend had his 8k mile old Mobil 1 from his Evo IX analyzed by Blackstone and it came back with enough additive package still remaining to be effective (3.1 TBN; anything >1.0 is satisfactory for use).

I love information like this. I told someone that I had over 5k on my oil and they looked at me like I didn't care for my car.

[1QUICK4]

I've always used Mobil 1 10w30 and never had an issue.

This Saturday I used Valvoline SynPower 5w30 synthetic (had it lying around) and Sunday I have rod knock.

Most likely a coincidence but I tell you what... I'm never using anything but Mobil1 10w30 and up again.