Stanadyne Diesel Performance Formula 38566, 64 Ounce

My mechanic said to avoid biodiesel, and use Stanadyne with every fill up. So I always do. Sometimes I get fuel that's part biodiesel. I had to get my EGR valve replaced a few years ago, as did the previous owner. But my 2005.5 Jetta TDI is running great now.

I have been using this product many years in all of my tractors and other diesel equipment and never had a fuel related issue Was getting harder to find it locally and was glad to find it on Amazon

Always curious how people give reviews on preventative products. I have had my Audi A7 TDI for 50k miles before I started using this at 110k and it always had a rough stop. After using 4oz per fill for 8-10 (5k miles) tanks I have noticed it now shuts down smoother. I am fairly certain this product is why. Personally I purchase the 64oz bottle and then put 8oz in a small juice bottle and keep it under the hood for two tanks making it much more cost effective. I plan to keep using this product.

This works really good in winter sub 10° temps in central KY in my 2022 Duramax 2500. I've been using this for 2 years now complaints!!

Price is better than any local parts store, does the Job

Stanadyne does not provide the results of HFRR results for this additive. Contacted them HFRR data - they answered that they outsourced additives to a different company (Parker Hannifin) and I should contact them. In my opinion if you name is on the bottle you should now stuff about it, or redirect the request accordingly, not to football people. According to Spicer Report on lubricity improvement additives this additive makes a tiny improvement: -33µm for values 350-400µm. Under 10%.Did not see data for cetane improvement.Bought lubricity formula from Opti Lube, will probably switch to them for Performance formula too. But not a bad product per se.

Does the cleaning job well

We use it in 90%+ of our fill ups. Sometimes, "she" forgets. Stanadyne is the only fuel additive to have VW's blessing, and with the fear developed from all of the reported HPFP failures on the '09+ Common Rail TDIs, generally thought to be caused by ULS Diesel's lower lubricity quality, why wouldn't you add some Stanadyne to every fill up?I have no empirical data, there is no seat-of-the pants increase in power, but there is a bump in MPGs, more noticeable in the Winter. Nothing drastic 1 - 1.5 MPGs. We use it because we still plan to be driving our '09 TDI Jetta another 200K+ miles, currently at 73K and counting.The 64oz bottle is usually the better value, unless buying in significant volume, which I may consider in the future. I keep a 16oz graduated bottle of Stanadyne DPF in the trunk with a long skinny funnel, when I use up the 16oz bottle I refill it from the 64oz jug.Thanks to the awesome fuel economy of the TDI 64oz lasts us a long time. We got about 10 months on the last jug, but we are traveling more now, so the idea of buying in bulk is becoming a bit more appealing.Bonus we got a free Diamond Diesel mouse pad/calendar with our purchase.