Customer Ratings & Reviews

When your car pick up is a little sluggish, you should put one bottle Of this Gasoline additive And you will see the difference in no time. Great stuff. You need to try it.

Use it in 7 of my vehicles every 5k and 1 vehicle recommends only super (high octane) been using regular gas and 1/2 bottle of this instead. No detonation, no loss of power, no oil consumption, great fuel mileage. Vehicle is now at 290k and still purrs.

Well recommended

Many people do not understand that the upper cylinder area stays "dry" and leads to wear and carbon deposits. Treating your fuel helps reduce wear and carbon deposits. Top tier fuels have some additives that help....AMSOIL finishes the job for me. Every tank gets this in my cars. It helps me trust those smaller gas stations that are not too tier fuels too.

How do you know if it helps? Just keep adding it to gas tank. Upper cylinders need extra lubing and the only way to really know if it is working properly is to tear down the engine and look at the parts. I'm not doing that, so I have to trust that it's helping.

I purchased a case of these on the recommendation of a friend. I was actually skeptical, and thought I’d try it out. After I got to .25 tank of fuel I added to fuel tank. (It works well in capless tanks). I filled the tank up with 93 octane that I always use. I didn’t notice much, except the power seemed to rise. The engine seemed more peppy. The mpg went up from 25.0 mpg to 25.2. The engine is able to run more efficiently, and with that comes a rise in horsepower. I really like this product, and add a bottle on every fill up.

This product seems to be working as advertised. I'm please with its purpose for use.

I run e40 ethanol in my Elantra N with a n upgraded intake and fuel system. I just feel it’s vital because of the high ethanol content of my blended fuel.

Trust Amsoil products if you want to keep it running forever!

Put 2 of these in everytime I fill up my F-150 (136 liters) and never have any problems. Acceleration and idling are always spot on!!!

I was skeptical that upper cylinder lubricant would increase power, but I can totally feel the difference.

I have used it for some time now and have zero issues with my engine at 300,000 kms. Amzoil says it is helpful and, given my happy history with their products, I am ok to believe them and continue to use it with every fill up!

With all the tight tolerances in these engines it’s a small price to pay to ensure everything is cared for 2014 Ford Taurus SHO

This was the first time I tried the product and I combined it with P. I., as always impressed with Amsoil!

This is the first car I’ve used this. Not sure how it’s going to work.

After putting this in my car after it's sat for 6 months during the winter and I drove it back home. It was great

Use every other tank, I found my car runs just as good on top of tank as the bottom so keep tank above 1/2 tank, if they want me to use every tank make smaller bottles. Car seems to be responsive when needed. Didn't seem to get better mileage but I have kind of lead foot. Neck seems to have problem opening inside flap on capless system at times so takes a little effort to get in tank without making a mess.

I put this product every oil change. Highly recommended by other AT4 owners.

I’ve owned 3 GM pick up trucks but my last one I purchased in 2019 I drained the motor oil out at 500 miles and I filled it up with Amsoil 0W20 Signature Series. I have about 71000 miles on my 6.2 L Sierra and every time I use the Amsoil Upper cylinder lubricant I feel a difference for the better and I think my MPG gets slightly better. It is a great product and every 4000 miles I follow up with P.I. Performance Improver gasoline additive. My 6.2 L motor is more happy and I enjoy my truck so much more. I’ll keep purchasing the Amsoil products.

This is an excellent fuel additive. I consistently use this for every fuel tank fill-up. Together with Performance Improver, this is a great combination to fight against Ethanol.