4 Bottles of Stanadyne 38564 Performance Formula 8 oz Diesel Fuel Additive

Worked as expected.

I got more mpg on a tank of gas I was getting 15 mpg and now its 16.5 mpg truck runs smoother and quieter great product

I add a little with every fill up. I can tell when i forget to add it. I have a dodge 3500 that is 24 years old. This stuff works great for start ups and keeps the truck running great.

A great fuel additive for diesel engines. I noticed a significant difference in how smooth the engine idles and runs when using this additive. I would have given it 5 stars if the containers had ounces markings on them. I typically fill my tank when it reaches 1/2 empty and therefore I only need 4 ounces. It would be nice if the 8oz bottles (actually, all container sizes) had a translucent fluid level indicator with oz markings.

I have been using this fuel additive for years and amazon has the best price.

Excellent product

Definitely quitens engine noise down. Seemed to make severe cold starts easier too. Hard to judge any change in mpg due to extended warm-up time in winter, but there is a noticeable difference in how smooth the engine runs.

Not sure if it's a placebo effect or not, but I've been using this with every fill-up on my 2011 Ford 6.7 diesel (the model with the sensitive fuel pump) for ~20K miles. No pump failures.