Fuel additives

Can the many closet car mechanics posting here help me understand if the fuel addititives and the other products for the engine that are usually sold at various auto parts stores are worth the money?

I’m just curious to see what is people’s experience with these things and if there is good stuff out there that we may want to know about.

Depends who you ask I guess… some people swear by injector cleaner. If I had a carb, I’d definitely be tossing a bottle of that stuff in once and a while. With EFI, I think regular fuel filter changes are a must, and keeping filthy jerry can gas usage to a minimum.

The octane boost stuff is BS though. If your engine isn’t knocking under hard acceleration, no need to bump up the octane. And if you do need higher octane, just get it from the pump.

I’ve heard bad things about oil cleaners. They do a very good job cleaning out the sludge buildup in an old engine–and can loosen up large deposits that were otherwise doing no harm, and can clog up some of the small oil passageways. Quality oil and regular changes is the best you can do in that department, if you ask me.

There’s another type of oil additive that promotes the oil sticking to parts. I’ve heard good stuff about these type in manual gear boxes, boasting easier shifting. I’ve also heard good stuff about synthetics in manual gear boxes as well.

People say good things about synthetic oils in general. You can go longer between changes with it, so it almost works out cheaper in the end. Oil filter brands differ wildly. Some good webpages out there explaining, with pics. Bottom line, Fram sucks the big one.

There was a great comprehensive study done by some dude on the Intertron regarding oil filters. He bought Fram, K&N, Canadian Tire, Napa, Lordco, Autosense, Mopar, Motorcraft, AC Delco, Pennzoil, whatever, and ripped them all apart.

Bottom line: The filters from the auto makers (Mopar, Motorcaft, Delco, etc) were the best.

Fuel additives: Injector cleaner is cool, octane booster not so… there are only certain rare situations (like trying to get your POS '82 Toyota to pass AirCare) where some more extreme additives are useful.

Engine oil additives come in a variety of flavours: Engine cleaners are pretty harsh stuff (most of them are mostly kerosene, I think) that act as a solvent, scouring your cylinder walls and valves and shit. Those should only be used like an oven cleaner: put 'em in, let them do their thing, then immediately change the oil and filter.

Oil thickeners are kinda sketchy. The idea is that if you’re leaking/burning oil, this can help prevent consumption. But the raison d’etre of your oil is to flow and lubricate, and thickening it does reduce its fluidity.

Anyhow, like Geoff said, the best thing to do is get your oil changed frequently. And if your mechanic says “hey,  your left handed widget o-ring is leaking” or “you’re puffing a little blue smoke, yo” and gives you a quote, maybe have a look yourself, and check for drips on the driveway and stuff, check your oil level periodically, and think about how severe it really is. As part of my job, I inform people about their oil leaks and things like that, and I really wish I could tell them, “Well, it’s going to be $200 to take that apart and change the gasket or seal it or whatever. You’re only losing a litre a month… $200 will buy you a lot of oil.”

Also like Geoff said, modern cars really like to have their fuel filter changed every few years. Unfortunately, on a lot of cars the filter is mounted right to the fuel pump, and requires taking the gas tank out to change. If it’s an inline filter mounted somewhere along the frame, though, even your Mr. Lube or Crappy Tire or whatever will have no problem changing it. Especially in coastal areas, and especially the farther you get from major distribution centers or refineries, you can be getting tainted gasoline, or fuel with too much water in it, even from the big brand name gas stations.

Anyhow, Bigthumb, do you have any particularly interest, or just curiousity? Is your ride giving you some grief?

Also, I really like “combustion chamber/intake cleaners” that come as a foaming aerosol that you spray down your throttle body/intake, then let sit for a few hours. The crap expands and foams like an oven cleaner.

Just about every time I have a car at work with poor compression, it’s not a major mechanical failure, it’s just gummed up valves and cylinder walls (I feel like the talking car from the Chevron commercial: “It’s not the valves’ fault!”).

Just curiosity.  My sonoma 2000 truck is ( knock on wood) in pretty good shape. 
I bought some injector cleaner the other day.  I don’t know if there is a difference but I figure it won’t hurt.  It’s just that there’s a whole pile of these products on the market and I just felt I might have been missing something as I’m not as mechanically inclined as you and Rangewreck.  BTW, when I opened the thread, I had a strange feeling that you two would respond quickly. 

You’ll notice we both have cars for our avatars :wink:

I swear by synthetics. When I bought my pathfinder it had conventional 5w30 and struggled to turn over/start in the cold. I promptly switched over to Mobil1 syntec, and also did the rest of the power train with synthetics. When I don’t have access to an outlet and its -30ish, the car starts fine. I also use gasoline antifreeze (methanol) and injection system cleaners… Generally STP or whatever is one sale at Canadian Tire. Up here, you need to.

“They” say not to use methylhydrate (gas line antifreeze) for fuel injected engines.

I say fuck 'em.

That stuff is neat. Is it safe for diesels?

I can’t think of why wouldn’t be, but I don’t know for certain.

I definitely wouldn’t use it on a new-new diesel (like an '07, with all the ‘ultra-low’ sulphur crap), because they have pretty touchy new exhaust systems where the catalyst is regenerated over time, or something like that.

I’ve been reading about this stuff lately… auto-rx.com/

The website is kinda cheesy looking, but do some Googling–people are saying nothing bad about it. It’s supposed to clean your engine out, but it does it very slowly, preventing large chunks of crud from breaking off and clogging oil passages. A lot of people are reporting much improved fuel economy, power, and leaks being stopped–especially on old engines. I think I’m almost sold on it.

Some guy set up a good page with comparison pics.

auto-rx.com/rms13/thumbnails … bum=10.htm

Which is hosted by the auto-rx site now, although it’s entirely independent (used to be self hosted).