A question about lubricants..

[Satan]

...specifically, those motor oil additives such as Duralube and Slick 50. Do they work? I always put a quart in when I do my first oil change on a new car, and this means I'll be needing to do this in a couple of months.

The commercials show tests which have engines running with no oil in them at all, and one lubricant (I think a "TV-only" infomercial type thing) even showed a big-ass engine running with no il pan and gravel being shoved in it!

They claim to actually treat the metal parts iinside the engine that allow clashing parts to smoothly interract, I believe.

So what's the Straight Dope on oil additives? Helpful, something which will neither help nor hurt or *gaso* actually damaging to an engine?
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[Gunslinger]

They do seem to work. We used to have a riding lawn mower with a broken oil slinger (IOW, no oil getting where it was supposed to. we poured a lot of Slick 50 in, and it ran for quite a while with no oil. eventually it seized up though.

[Steve-o]

FWIW, my mechanic recomends them. It should be noted that he sells the stuff, but at the same time, I've stuck with this guy for several years because I believe him trustworthy. He's a little more expensive than most, but half the time, he sends me away with a much smaller bill, and fewer repairs than I thought I needed going in. The only mechanic I've ever had that experience with.

[Lance Turbo]

The Skeptic's Dictionary on Slick 50 (http://www.skepdic.com/slick50.html)

[sailor]

I have always heard you should use water-based lubricants because petroleum-based can damage the condom with unintended consequences...

[Rysdad]

An acquaintance that was a manager for a Firestone maintenance facility said that those additives were indeed excellent lubricants. So good, in fact, that they would leak out of the gaskets much more easily than regular oil.

So, if you use them, check your valve covers, I guess.

YMMV

[casdave]

If you have a motorbike with a wet clutch, as most are, do not under any circumstances used these products.
They will cause clutch plate slippage.

[cornflakes]

QUAKER STATE SUBSIDIARIES SETTLE FTC CHARGES (http://www.ftc.gov/opa/1997/9707/slick.htm) AGAINST SLICK 50

Dupont makes PTFE (teflon), and advises against using it as an oil additive. IIRC, it doesn't melt, so it tends to clog filters and passages.

Prolong Super Lubricants Settles FTC Charges (http://www.ftc.gov/opa/1999/9909/prolong.htm)

So I guess you can't stuff rocks into your crankcase either.

My guess, FWIW, is that a cool engine should have enough of an oil film on the bearings that it could run for the length of a commercial. I was once told that one API oil grade required an engine to run with the oil drained for a set period of time. I doubt it, but I'm sure that film strength is an API requirement.

[cornflakes]

Oops:...a cool engine should have enough of an oil film on the bearings that it could run dry, without oil for the length of a commercial.

[Meephead]

As Stated above, Dupont does not recommend Teflon as an oil additive, but there are other additives that are marketed, too... Motor Up! for example, contains a zinc compound. Most motor oils contain at least a little zinc. Its purpose is to prolong engine life if you run out of oil. Too much Zinc, however, can lead to spark plug fouling...use at your own risk.

For more accurate information, here's a link that is very enlightening:
http://www.vettenet.org/oiladds.html

[Ike Witt]

I thought that this was going to be a follow up the the "You want to stick that, where?" thread.

[London_Calling]

Damn, this thread's got an awful lot of page views for a motor oil subject.