Are additives worth the price

When you go into the auto dept of a store, there are all kinds of things to add to your gas or oil to supposedly make your car run better. I’m not talking so much about “dry gas” which I do use to help with winter starts, but about oil products such as Marvel Mystery Oil and oils “specially formulated” for use in engines over 100,000 miles. I did use them in my old car (a 1987 Dodge Caravan), but I recently got a much newer one (2003 Chevy Malibu), with a different type of engine (fuel injection instead of the old carburator, for one example), and wonder if they do work. The dealer, by the way, was actually neutral on this, said they weren’t necessary, but some people do like them, so he’ll put them in if asked. No huge sales pitch like at some other places I’ve been to. With my car only 5 years old, and purchased with 100k (mostly highway, I was told) already on it, I’d like to protect my investment on it. Your thoughts on this would be welcome.

Unless you are experiencing a driveability problem that can be attributed to partially clogged fuel injectors (a fairly rare occurrence), don’t waste your money on fuel additives.

So-called “high mileage” oils don’t help an engine in good condition, and probably don’t help those that aren’t.

i have heard of some oil additives that help or contribute to oil break down at high temperatures in fact i think mobil 1 doesnt recomend the use of such additives on their blend and syntec oils.

"The dealer, by the way, was actually neutral on this, said they weren’t necessary… "

You found a rare bird, an honest salesman.

He is absolutely correct. None of these additives are necessary and when added to a healthy car they will do absolutely nothing. Some products can help a problem situation for a while, such as the dri-gas that you mentioned, and maybe some stop-leak products. But don’t waste your money on regular health tonic for your car. You will derive no benefits.

Yes 100% worth the cost, IF you are having a problem that they can address. They are also worth it if they are part of the package that is already in the oil and fuel you buy. Other than that, they are a waste of money at best.

If you look around you will see that the regulars here do recommend additives on occasion for special problems and sometimes they work.

When I do a oil change with regular Dyno oil I like to replace one quart of oil with a quart of Rislone. It’s really good at keeping the engine clean and helping start the car when it’s -10 out. But since using Synthetic I haven’t found the need.

Now if you’re having a problem like sludge…then something like Rislone is GREAT.

re:you found…an honest salesman-- yes, I did, but since I live in a relatively small town in New England, if one wants to stay in business with a good reputation, one HAS to be honest!! This dealership is a family business, the current owner/manager being the grandson of the founder, so he is well known in the area, and if something goes wrong, he is good about trying to make it right, lest public opinion cost him business!! Aside from that, I posted the question because I am, except for listening to you guys (and CarTalk), relatively unschooled about things automotive, hence the question- is it worth it to buy oil “specially formulated for older engines” or to get Marvel Mystery Oil, which the auto parts chain store in town does recommend and has on sale from time to time. I could certainly see it (and did use it) in my old car, but with new cars being so much more advanced, that’s why I wonder how much is still good, and how much is hype. Thanks again for your input.