Air/Fuel Separator

[bsmith0404]

I have been looking at the Air/Fuel separators from FASS and Air Dog. They claim to help injector life, I can see/understand that as a possibility. Diesel owners all know how bad diesel can foam and there is the possibility that air can make it to the injectors,. That was the partial blame for some of the injector problems on the older duramax. They also claim that you get a better shot of fuel which increases horsepower and improves fuel mileage.

At $500-700 it is a big punch to the wallet and I am very skeptical of the benefit to cost ratio. Any thoughts?.

[bsmith0404]

Okay, I've modified my original post some. There has to be some people out there with opinions/thought/experience with these systems. I'm checking the diesel forums as well, but a lot of the people over there are into performance mods for the sake of performance not for longevity and towing.

[jtyphoid]

I'm skeptical about the need. Yes, diesel foams, but the foam floats and dissipates rather quickly and the fuel pickup is at the bottom of the tank. Unless there's a design flaw in the fuel system or some other unusual situation, I don't see the need.

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[Bob Landry]

If air makes it to the injectors, the engine shuts down and you have to bleed it from the high pressure pump. There is air in the tank because the tank is a vented system, but the pickup is on the bottom, so nothing but liquid fuel gets sucked up. I serviced small sailboat diesels for years and never had a fuel foaming problem, never herd of it. The only air problems I encountered was from cracked fuel hoses and faulty fittings sucking air between the tank and the lift pump. I'm going to have to call BS on that one.

[bsmith0404]

I first saw info on these systems in a diesel truck magazine where they brought up the concern of the injectors. The basic message was small (microscopic) amounts of air will cause the injector to slam shut vs. a smooth cushioned closing on fuel. The "diesel experts" stated this slamming action and the lack of lubrication from the low sulfur fuels is the major cause of injector failure.

I've looked at quite a few different post and reviews, for the most part it's been mixed. Some say they noticed immediate results with a smoother running and more responsive motor. Others said the results were minimal and the power/fuel mileage gains were not as much as expected for the cost. One guy made his own system based on a design from an engineering major in college and raved about how much better his power stroke performed. So it seems as though there are noticeable improvements/results, but the cost vs reward is questionable.

Sounds like $500 for a product that may or may not benefit the truck is money better spent somewhere else.

[GMcKenzie]

As an aside, not convinced this is the problem with the early Duramax injectors. After reading up and dealing with my own, there is just something wrong with them.

[jsmith948]

If you are concerned with the lower lubricity of ultra low-sulfur fuel, you could use an additive that increases lubricity such as 'Power Service Diesel Clean'.
Agree with previous posts - foaming is a non-issue. JMHO

On edit: When I started out driving over the road, diesel fuel was some pretty nasty stuff. It stunk (smelled like sulfur - go figure), it was dark in color and actually felt 'gritty'. I have read comments on here about the poor quality of today's diesel, but, I think the low sulfur fuels are better. Less corrosion, less water in the fuel vendors' tanks. I'm sure one can still find a load of 'bad' diesel out there. But I haven't had to stop 50 miles from the fuel stop to change fuel filters in a long, long time. The fuel I buy today feels clean and smooth, and, is a nice, clear to bluish color. Of course, it costs a bunch more! Just sayin'