Customer Ratings & Reviews

Crossing multiple state lines and fuel quality in question this stuff will help with condition, lubricity and increase fuel efficiency.

Much needed here in Alaska

Much needed here in Alaska

Makes the truck run great

Raises cetane level so I get better fuel mileage. Removes water keeps from gelling. Use it in both vehicles. Duramax and baby Duramax.

I HAVE USED AMSOIL DIESEL ADDITIVE SINCE 2008 IT HAS WORKED WELL. OUR WINTERS CAN LAST FROM OCTOBER TO MAY

Have Not had any adverse affects from using this product and have not had any fuel gelling problems in severe cold weather.

Purchased my first bottle from a friend to try to deviate from Lucas additives. It woke my LB7 up and I decided to buy a whole case to have on hand. Highly recommended.

My engine runs quieter and I get 1.5 miles per gallon better fuel economy. I have been using it for years.

Noticeable mpg by 2mpg improvement and also a good peace of mind fuel system is getting the best liberation out there to keep parts happy and healthy longer

I have over 300k on my '06 LBZ Duramax and I use this every fillup. Still running original turbo and injectors and EGR valve. The exhaust is much cleaner even when rolling coal getting on it on the freeway. Also use it in my Kawasaki Trans Diesel Mule, CAT excavator and Mahindra tractor.

Ordering process was seamless. Received 4-1 Diesel additive in a few days. Received it mid-summer. Will let you know next spring how well it performed over the winter. So far, so good!

I’ve been using this in my 2019 RAM 3500 DRW from day one with no problems whatsoever.

I have used Amsoil's Diesel Fuel supplements for many years (220K Miles) with great success, just another great product from a great company!

I use this in my LMM Duramax year round. I do trust it.

I use this in an Audi A6 diesel. I had trouble with the check engine light coming on due to an oxygen senser. Since I started using 4-in-1 it has not triggered the light. a longer time trial will help confirm. Fuel mileage has definitely improved by a few gallons.

Très bon produit mon vieux 6.5 détroit l'aime bien, mon mpg c'est améliorer!

I use this regularly

Today’s diesel is missing vital additives that prevent issues and increase longevity, this stuff brings your fuel right up to par.

My vehicles run well using this. Jeep ,ram,Mercedes and bobcat.