Customer Ratings & Reviews

I have been using this for years in all my vehicles. I trust Amsoil to supply me with the best products to protect my vehicles. I have never had an issue with any part of my vehicles that are Amsoil protected.

Excellent product with results!

Great products, Fast shipping, Great savings with club ...

Threw this in and and changed to AMSOIL full synthetic 5w30 and my 350 purrs like a kitten. Thanks, highly recommended!!!

I plan to keep my vehicles running top condition and with upper cylinder lube I trust that.

Engines need to be lubed and this product seems to be the ticket for that added help.

Both my vehicles are fairly new but I use Amsoil upper cylinder lubricant regularly and both engines seem quieter than when I first purchased the vehicles. Very impressed.

I add UCL to every fillup and notice my car runs better in terms of smoother acceleration, even though I use high-quality gasoline (Costco, Shell, Mobil or Chevron only). If they don't increase the price I'll continue to add one with every fill-up.

Really depend on this as I do a lot of towing.

Put this in my mower and generator. Both run a lot smoother

The stuff works great, car still runs like new with over 200k miles. Little disappointed that I spent over$100 on my last order and did not receive the shop towels

Overall product quality is a 5 stars, Amsoil requiring you buying a bunch of bottles is 2 stars at best and I rate this overall 3 This product evened out my idle and my engine is running much smoother on a 2007 Scion tC, I also put it in a 2019 Buick Encore which seems to have had an immediate effect of better gas mileage. The problem with this product is you have to use it consistently (emphasis here), which requires you to buy a bunch of these bottles, I think Amsoil should sell it as a large bottle so you can divvy up your own from a measuring cup or dispenser, that would save on the plastic and hopefully bring down the price. Sell it in quarts or higher quantities and provide in the instructions the recommended administered quantity for the treatment of gas. I really like this product so far but cant justify buying 100's of small bottles, when they could just put it in a larger jug, as this is the only product I can find that I trust... I will be stuck paying for it begrudgingly.

I have a 2013 Fusion with 132,000 miles in it. I been using Seafoam every 3 to 6 months and at idle or stopped at light it ran a little ruff. After using UCL it seems to be running a lot smoother and feels like it has more horsepower. I know the quality of gas can make a difference. I only use it once a month. I would recommend it.

Have used this in everything from 60s era solid lifter V8s, quieting up the top end to getting cars with dirty injectors to come back to life, I’ve also used this straight as a cleaning fluid in an injector sonic cleaner and it works better than Tektron.

I had always used Lucas injection cleaner and upper end lube without any issues but I tried the Amsoil product and could tell right away that it cleans better and makes the engine perform better

Yes it seems to work great with the combo with the P.I. so just using this additive by itself--I haven't but I'm more going into this fight like a boxer--This additive and 2 weeks later the P.I.--1 - 2-- punch

I run this in my harley and my high mileage For Ranger. It has helped with cold starts and engine temperatures.

Noticed no difference

I was skeptical at first having tried so many products in the past now this upper lubricant works, it does everything is advertises. My Toyota tundra now has better gas mileage and performance!

Most of the time I carry a couple bottles when I'm driving in Mexico and getting gas in a questionable spot. Not sure if it did our has helped but makes me feel better lol. I have found just running ethanol free gas seems to make more of a difference. I almost never use fuel additives.