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

I used as directed and gave me the results I was expecting,

Does the job as described

Recommended by the dealer for my newer model GMC diesel pickup and so far it has proven itself to work. When the engine seems to be running a little more sluggish or the DEF system doesn't seem to be operating as well I add a bottle of this, to the fuel tank at fill up and everything seems to improve. I've had my check engine light come on for emissions system issues a couple times and this has helped resolved the issue. It's a little bit expensive so I add it once every 4 to 6 weeks at the most.

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.

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.

Shipping was quick, price is competitive with other distributors. Stanadyne performance speaks for itself.

Great product. Can tell the difference with first tank. Also use in my tractor with no regens

Gives power almost immediately