Do engine treatments like Slick 50 really work?

Slick 50 use to say their main ingredient was Teflon. DuPont was very skeptical of Slick 50s claim so they did their own testing. When their testing was done they told Slick 50 they can no longer use the name Teflon in their advertising and forced them to remove it. Since the Slick 50 replaced it with the chemical name for Teflon -PTFE.

The other ingredient is 50W oil. If your engine calls for that, then great. Most don’t and this is likely not something you want to use unless you have an oil burner you are trying to limp along a few more months. The 50W oil may be why the transmission shifted better after t was added. Remember that gear oil is thicker than regular oil. I always see those Lucas demos in the parts store where you turn the crank and watch it stick to the gears much better than the motor oil. It is great gear oil but I don’t want it in my engine either.

I have used some cleaners such as Seafoam and Marvel Mystery Oil not long before changing the oil in engines that are severely neglected. These are probably not needed if you have been good about changing the oil and there is no sludge buildup.

If you want to really get good oil, buy synthetic matching the specs for the car you drive. I do this and get it on sale in bulk so always have it when needed. It is no more expensive to do it this way and may be cheaper than normal-priced conventional oil. Also remember that the rest of the car will likely rust away before you have to worry about engine issues if you change the oil as called for with regular oil.

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I need seafoam in gas my boat, treat my car gas with it occasionally, hands over head waiting for bricks to fall.

Not all additives are snake oil and likewise not all additives are affective. I have several vehicles 2017 wrx 8k odo, 2015 Chevy Tahoe 92k odo, 2003 GMC Sierra 1500 190k odo and a 2004 jeep grand cherokee with 4.0 6cyl engine with 280 k.
I have used oil additives in the GMC and in the jeep due to the high mileage. All have been maintainedited properly and with recommend oil except the GMC and Jeep because of the mileage and the kind of use I get out of them. I drop chevron techron in the fuele tank every oil change 3kmies and all of them work great. I also use a bottle of restore engine treatment in the 2 vehicles. I use restore oil treatment in the high mileage vehicles and use seafoam to clean out throttle buddies and throttle plates. This by the way gives immediate performance improvement. Pour right into throttle plates slowly and keep the engine from dieing. It will blow black smoke. Hold it at 13 15k rpm till it clear out and go for a rest drive. If you have never done this and your vehicle has more than 90k Mile’s you will notice an immediate improvement in performance and smoothness of idle. It may turn on check engine light. If it does just clear it.
With all that said I am a proponent of additives but agree that there are plenty of snake oil options out there. Do some research. Seafoam, techron and Restore engine treatment for high milage vehicles.
On a side note Lucas oil treatment caused a spun main bearing in a jeep I previously owned. Good in gears not in engines.

WOW. I’ve never seen a Jeep or GMC engine that could withstand 13,000 - 15,000 rpm and survive.


Maybe is an accountant. They move those commas around to suit the situation.


I’ve never seen a Jeep or GMC that had a Tac that went that high.

I’ve owned 1987 Accord with over 300k miles, 1996 Accord with over 250k miles (then gave to niece when she went to college and put another 100k miles before she sold it), 1990 Nissan Pathfinder with over 300k miles, 1998 pathfinder with over 400k miles…NONE of those vehicles used any kind of oil treatment and they were still running great when we sold them. Because you used the additives and were able to achieve higher mileage, doesn’t mean it was the additives that allowed it to happen. All it means is that they didn’t prevent you from achieving higher mileage. I’d bet that if you hadn’t used the additives the vehicles would still have reached the same mileage.


I got my 1988 Nissan truck (Z24 4 cylinder engine) at 88,000 miles and drove it another 100k, to around 180,000 miles. At that point it needed a valve job so i decided to do an in car overhaul too, and change the timing chain and the tensioner. Also all the time i owned it i too, changed the oil at 2,000 to 3,000 miles and I will tell you what i found inside when i took all this apart.

I needed the valve job because of one burned exhaust valve. I always adjusted the valves myself, carefully, so I’m not sure why it happened but it did. But I just got a remanufactured cylinder head for $300 (this was in 2000 i did all this). I removed the oil pan and the timing chain cover to change the chain. The timing chain was like new, almost no visible wear, no teeth marks and compared to the brand new one, could have done another 50,000 at least if not 100. The chain tensioner was a rubber spring loaded part, worn to nothing and really the only part that actually needed changing.

The inside of the oil pan was very clean with no trace of sludge. (By comparison, I have removed the pan on other cars where there was literally two inches of sludge that had to be removed with a putty knife). When I unbolted the connecting rods to bring the pistons out of the top and change the rings. I bought a cylinder reamer (tool that removes the ridge sometimes present at the top of the cylinders) but there was no ridge so this tool was not even needed. The pistons and con rod bearings looked good so I put them back in. All i did was clean the ring grooves - they had very little carbon in them and it took me an hour to clean all of them. Right after I pulled them out of their holes though, i was careful to mark the pistons for direction and which cylinder they came out of, if you are reusing pistons this is important to do). All i did was change the rings, stagger them per the instructions, and soak the pistons in a coffee can full of oil while i did other things. I honed the cylinders myself since there seemed no reason to do anything more then that. Then I cleaned inside the cylinders like a clean freak - first acetone, then brake cleaner, then ATF on a rag. Then brake cleaner again til a paper towel wiped in the cylinders, stayed white. Put it all back together using assembly lube and plenty of oil, buttoned it up and reattached the battery, turned the key and it cranked - NO START!

I cranked for a half a minute, then stopped and thought about things for a minute…did i put the distributor back in right or did i put it backwards? I unbolted that, reversed it 180 degrees, bolted it back in. Turned the key and the engine instantly started up! WHEW.

The point is, I did see for myself just how little an engine wears when you change the oil as often as careful owners like you and I do! And i also used Slick 50 once or twice as well. But i drained the oil out at the next 3,000 miles anyway, Slick 50 or not - and did not reuse the Slick 50 again for a long time - I doubt this stuff made any difference. I finally got rid of the truck because it wouldn’t pass the dam smog checks (it wouldn’t idle low enough) and i just gave up on trying to keep it in service because of the nightmare smog C.F. hassle every single year - NOT because it was worn out. The idle was slightly lumpy but the engine had plenty of power, as much as when I got it and if not for the smog check thing, would have driven it another 5 years. But when you change the oil often, something else is going to quit working that will probably make you dump the vehicle - but chances are it won’t be because the engine wore out.

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In one of John Scarne’s books about gambling he told the story of a casino owner confronted by a disappointed slot machine loser user who said his machines didn’t pay. He disagreed, pointing out that they pay the rent, the lights, the water…


This is SPAM. Moderators…please remove.

I believe you! I’ve been using “slick 50” for years as a matter of fact a lot of police and fire departments use it in their vehicles. I know it works because I’ve used it in small engines and empty the crankcase on one and the motor ran 10 minutes with no oil in it! Started knocking so I turned it off and added oil it’s still running today! it WORKS!! And no amount of anti-slick 50 posts and adds will convince me otherwise. Been using it for over 15 years in my 1996 Chevy Truck every 3rd oil change I add Slick 50 and I’m at 245,000 miles and engine runs like its new and still running.

I depends on what you want it to accomplish. It can help minimize lifter noise on a cold engine with lots of mileage.

Sounds like BS to me. At best you change your oil as needed, and your engine isn’t worn out. Don’t need Slick 50 for that.

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I would attribute that to the superior quality of GM truck engines from the 1990’s to 2000’s, and proper maintenance, not the use of Slick-50. I currently have a 2000 Chevrolet Silverado with the 4.8L engine, and even with over 209,000 miles, it starts instantly on the first try, and idles so smoothly that I find myself looking at the tachometer to make sure the engine is still running.

I have never owned another vehicle which doesn’t require multiple tries to start, and doesn’t shake or vibrate when stopped at a light. Even my 2004 Toyota Corolla, which runs reasonably well, has a noticeable vibration at idle, and had it since it was new.

Why the heck would you deliberately abuse the motor like that . . . ?!

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Back when Slick-50 was being pushed hard on television a customer left his truck for regular maintenance and brought a can of the additive to be added to the crankcase. The work order was picked up by a young mechanic and parked outside when finished without adding the Slick-50. Some time after 10:00 that night the owner called me at home from 200 miles away to brag just how great his truck was running and how little gas it used on the trip. I just kept quiet and the next time the truck was in added the can but he was sure that there was a great improvement in performance.

There are lots of automotive additives that serve a specific purpose and when needed their use can improve performance or lengthen the service life but none are miracles and those like Slick-50 that make miraculous claims are the least effective of all that are on the market it would appear. But of course that’s just my observation and opinion.


Slick 50 is snake oil. Of course it works great for the naive and those buying into placebos and I simply cannot give much credence to anyone who intentionally runs an engine sans oil in it. At some point it is going to give up because of that stunt.

As for the poster back in May 17, Lucas oil treatment did NOT cause a spun bearing in a Jeep. That was caused by excessive wear with excessive oil clearance and the bearing shifted sides because of the heavy viscosity Lucas.
The same thing can happen if one was to run 20/50, straight 40 weight, or any other additive which thickens the oil up.

nothing like dragging up a useless 10 year old thread.


And no amount of anecdotal testimonies will convince me I should have spent one dime on oil additives for my 1988 Accord that I sold to a friend running like new at 220k miles, and I last saw still running fine at 270k.
Now I ride a bike to work, and don’t even do that lately with COVID, so I don’t put many miles on my cars.
Previous car had 68k miles in 12 years before a hit-and-run driver totaled it.


And my 1998 Nissan Pathfinder finally died at near 500k miles and I it never ever had any oil additives what-so-ever. We’ve maintained at least 5 vehicles over 300k miles and were still running strong when we got rid of them.

As I stated several years ago in this thread…Dupont (the creator of Teflon) the active ingredient in Slick-50 won’t work in this type of application. They forced Slick-50 to remove the name Teflon from their packaging about 20+ years ago. Now Slick-50 uses the chemical name (PTFE).