Thanks to our illustrious server guy, I plucked the nugget of idea for this thread from the shoutbox.
I’m fairly certain that there are a number of individuals who are somewhat mechanically inclined here, although it is open to all. Pretty much everyone has an opinion on this, and some folks get downright reverent about it.
It has nothing to do with our usual topics…what I’m talkin’ about is OIL!

That’s right…dead dino juice…blood of the earth…blessings from our carboniferous past. Whether natural, synthetic, or goat piss in a radiator, fluids are supremely important to the well being of any mechanical construct.
So, let’s hear it, Planeteers! What is your "House Earl"? Why do you like it? What grinds your proverbial (hopefully not literal) gears after you tried something different? What are the things you’d not put in on a bet?
For synthetic oil, I absolutely LOVE Pennzoil Ultra. Shit is god-awful expensive, but I’ve seen it outperform boutique oils in my apps. Super clean, super slick, and the most advanced add pack I’ve seen. Some of the fattest amounts of boron anywhere I’ve found, which is awesome for cylinder walls.

Boutique oils are a subject of much debate…some folks think they’re a waste of money, others swear only theirs is the greatest. Lots of folks love AMSoil, some folks can’t resist Royal Purpley goodness, I’m a Redline guy.

This is going to sound a bit odd, but I’m more a Redline guy for their product line as opposed to ‘just’ their oils. Nothing against their oils; I think they’re good product too. However, I’ve done some pretty neat shizz with gearboxes and their D6 tranny fluid. Low viscosity and slick as fuck. Most awesome is that it’s pre-sheared; this is what normally breaks a fluid down to ineffectiveness and kills your engine and/or tranny if you let it. This magic and utterly foul-smelling concoction is already broke down about as much as it can be mechanically before it even goes in. The Water Wetter is very cool…literally. Chemical magic that will lower your operating temps noticeably. For standard apps, their gear oil is as good as any I’ve found also. Good range of viscosities available make it easy to tweak your fluid to your app with maximum benefit.
I *like* the Royal Purple, I think it’s good oil…but the purple is gimmicky as hell. It’s just a dye. They’re supposed to be using some proprietary long-chain molecule, but I’m not totally sold on it’s effectiveness. Some of their previous promo testing is highly dubious as well. Within a day, it just looks like really nasty old oil to me, which kind of defeats the purpose. The state of an oil in use should be visually verifiable to those who know how to read it, IMHO, and that kinda defeats the whole purpose in favor of ‘it’s purple!’. I’ll hunt Pennz Ultra before paying for RP, if it’s at all a choice. Really, I’m not convinced RP is any better than any run-of-the-mill synthetic.
For quick-and-cheap, Peak ain’t bad. It shears quickly, unfortunately, but it’s good for regularly changed apps on a shoestring budget.
Once, when I was young and foolish, I was a ‘Quaker State guy’. Unfortunately, I learned the hard way about sludge. Waaaaay too waxy. This was not such a bad thing in older engines, as they’d usually crap out before it became a problem from something else, but if you’re trying to push that beater for another hundred thou just don’t even let QS cross your mind. Even with regular changes, this stuff will sludge up your internals something awful.
Oil getting a little thin, but can’t change it just yet? Hit it with some Lucas-love the stuff. Their long-chain molecules are readily apparent in this mix – the stuff will literally stretch for feet from the cap in tiny stringers. It doesn’t have everything, it’s not a standalone add pack, but it will refresh oil that’s sheared out a bit and is a good thing to add to cheaper oils to improve their characteristics.
Firm believer in Seafoam for anything with a carby. Fuel injection, not so much. About any cheapass alcohol-based cleaner will do more or less the same. I have been known to use a little Heet from time to time during cold snaps.
Marvel Mystery Oil…I just don’t understand lol Lots of folks swear by it, but I’ve never looked into it too deeply. Guess that’s the ‘mystery’ part…
*All of these are my fucking opinions, it’s not gospel. Royal Purple Planeteers, don’t take it personal. 😛