I use Howes. Power Service improves my fuel economy by exactly zero. FOr what it does, Power Service is great. It provided lubricity, disperses water, engine boost, etc., but Howes does all that with less ounces per tank, and has the added benefit of giving me better fuel mileage.
Howes Diesel Treat, the amber lookin' stuff in the clear half gallon bottle, says on the label:
Summer/Winter Formula
Diesel Conditioner
Anti Gel
That "Anti Gel" part is what makes many people not use it in the summer, cause, "What do I need anti gel for in the summer?"
As a result, Howes came up with Meaner Power Kleaner for people to use in the summer. But it's more than that.
The Diesel Treat is made for use in both summer and winter. Simply use more of it the colder it gets.
Summer - 2 oz per 25 gallons (1 oz to 12 gallons)
Winter -32F - 4 oz per 25 gallons (1 oz to 4 gallons)
Sub-Zero - 12 oz per 25 gallons (1 oz to 2 gallons)
Howes Diesel Treat is a general purpose treatment, much like all the others, except that instead of a cetane boost, which makes the fuel burn more completely, thereby burning up contaminants, Diesel Treat reduces the surface tension of the fuel at the dispersion point, allowing it to burn as completely as a cetane booster, without the added heat buildup of most cetane boosters.
It's a small distinction, but I believe an important one, since these turbo diesels already run hot, and the ULSD only makes them run hotter. For this reason, Howes recommends using 1 oz to 2 gallons at all times for cars and light duty trucks, which is the same as the formula for winter temperatures above zero degrees F. That's lots of lubricity and lots of efficient fuel burning, but that's a lot of additive, IMHO.
Some people want a cetane booster because they think they want more power (argh, argh, argh) without really knowing why the additional cetane matters. It's all about burning the fuel as completely as possible, and more cetane, being more energy per gallon, gives you that. These are the same people that faithfully watch the radar gun at baseball games, and think Greg Maddux is an over the hill hack 'cause he can't
bring it.
1 oz to 2 gallons
at all times seems overkill to me, but it will give these engines the added lubricity and completeness of fuel burning necessary, without adding the extra heat.
The Howes Meaner Power Kleaner is pretty much the same as the Diesel Treat except it's cleaning properties and lubricity properties are more concentrated. With the injectors on these Sprinter engines being what they are, you can't keep them too clean. Bottle says 8 oz for 60 gallons, which translates to 3.33 ounces for a 25 gallon tank (or 2 ounces for every 15 gallons). I have found that I get about 1 MPG improvement with 3-4 oz, and nearly 2 MPG with 6-8 ounces. But, there is a point of diminishing return if you use too much. It reaches a point where the MPG savings doesn't overcome the additional cost of the additive.
What I do, instead of the seemingly overkill of 1 oz per 2 gallons of Diesel Treat all the time, which will give the engine, fuel pump, etc., all the lubricity it needs, I put in a couple of ounces of Diesel Treat per 25 gallon tank, and about 4-6 ounces of Meaner Power Kleaner.
I just eyeball it, filling through a funnel. The bottle is marked, making relatively accurate amounts easy to figure out. A too few or too much of one or the other it doesn't matter that much. (Too much Power Service, though, and you'll see hit on your MPG.)
The Power Kleaner used to be relatively cheap at about $9 a bottle. Thanks to a massive promotion campaign, it's as high as $13 a bottle in some places. Don't buy it at those places.
If I run into it at a high price, I'll skip it for a tankful or more until I can find it cheaper. I just adjust the amount of Diesel Treat I use in order to keep up the lubricity.
If I only have one or the other on hand (and I'm too lazy to go inside and buy what I don't have), it'll be the Power Kleaner, as it does all the stuff the Diesel Treat does, plus the more thorough cleaning of the injectors. In the colder winter months, however, I'm not likely to be without Diesel Treat. In the coldest of winter months, that's when I might use an actual cetane booster like Power service, to help with the fuel combustion at the colder temps.
But when I use both products, I find that I get between 1-2 MPG, a smoother and quieter engine, less smoke, and essentially no water in the fuel filter water separator. Power Service is a water separator, a de-emulsifier, which enables the fuel filter separator to capture the water where it can be drained off (or more easily frozen inside the filter hehe) or it simply settles to the bottom of the tank (great for big rigs, not so great for the Sprinter, at least, because of from where in the tank the fuel line draws the fuel). Diesel Treat is a water emulsifier, which essentially encapsulates the water molecules and burns them off in the combustion process. The Power Klean ensures that anything left behind in the steaming-off process from the water being burned off is cleaned out.
All the little things, de-emulsifiers versus emulsifiers water separation in the tank, and cetane boosters, etc., probably aren't all that big a deal in the larger diesel engines, but for car and light duty diesels, it can make a big difference, both long and short term.
Standyne, Power Service, Howes, many others, whatever your choose, you mainly want something that will get rid of the water in one way or the other, added lubricity especially with ULSD, and something that cleans. For my money, because of how picky the Sprinter is with fuel injectors, fuel filter, combustion heat and other factors, and the added fuel economy I get with it, the combination of the Diesel Treat and Power Klean seems to be the best solution for both the short term (fuel economy) and the long term (cleaner engine and injectors).
Your mileage may vary.
