First cold snap in years without fighting plugged filters...

...only difference? Previous 6 years with Holiday Station Stores, fleet card. This year, switched to BP. Haven't plugged a filter, yet.

I think its all about fuel quality when it gets to -15F or lower. If the fuel is carrying water, its eventually going to freeze enough in the filter element to cause a 'low fuel rail pressure' limp (LLYs or newer).

If you travel in the northland, carry 'the kit' :

• Spare OEM Delco fuel filter
• Mechanix gloves for grip and feel, without frozen fingers
• Wrench for removing water-in-fuel sensor (BTW...has anyone actually seen this light illuminated on a Duramax yet?)
• Red bottle '911'

I also caution against excessive idling after a severe cold start. One minute, tops. Then get moving and use a gear that will keep your RPMS elevated >2500 until you have 160F water temps - it gets your fuel temperature up, quicker. The more cold fuel that must pass through the (initially -20F) filter casing and element, the more likely it is to plug...the faster the fuel gets warm, the better!

1. Good fuel - pretreat if you have been having problems from the same source, before the cold snap!
2. Starting / warmup procedures.
3. Spare filter.
4. 911 red bottle treatment, as a last resort - most effective AFTER changing to a new filter, to avoid plugging that one...

A GM tech jokingly told me that the Water in Fuel light only illuminates after a gallon of water runs out of the tailpipe. Too funny. I think once you do really see it, you probably already have a real problem.

Has anybody ever tried aftermarket FWS? I'm beginning to wonder if water is playing a role in some of the fuel system problems I'm now scared of.

Evidence:
1) Sounds like our factory FWS and sensor doesn't catch much.
2) The last filter revision sounds like it's more focused on removal of water than particles
3) Reports of rust in fuel lines when injectors are replaced.

There's some aftermarket FWS options for commercial trucks. I'm tempted to try one with a clear bowl to see what it catches, but don't want to waste $ if somebody's already ruled that out.

I think you'd trap and remove lots of water from the fuel we are being sold these days! It also seems that the water/filter plugging problem increased when we started blending bio-diesel in Minnesota, but can't prove that of course.

http://www.boatersworld.com/product/..._source=google

I used to secure an 80 gallon red farm-type transfer tank in the bed of my truck, for fueling skidsteers on snowplowing jobsites. It had a hand pump, with a clear plastic filter housing. (Never used dyed offroad, always the same taxed road fuel as I was running in the trucks, didn't want to end up with an employee pumping some into the commercial tanks, and risk a $10K DOT fine...) :eek:

~80 gallons of fuel would usually result in 2-3 tablespoons of water collected at the bottom of the clear filter housing. It was easily drained off by opening the petcock at the bottom. After we started filtering and fueling the skidders from this tank, we never plugged a Bobcat filter again. When we fueled them at the Holiday Station Stores directly from the pump, we changed Bobcat fuel filters at every January cold snap, when they would plug...

My understanding is the new elements of the GM OEM filters absorb and trap the water, rather than reject it. The 'Tractor Supply' type cartridge filters used in my hand pump transfer tank rejected the water, and it ended up at the bottom of the filter housing. Further evidence of this is that we never see the WIF dash indicator coming on, which would happen eventually if water were accumulating in the filter housing.

The problem in cold climates is that same trapped water freezes in the filter element, and eventually causes a low fuel rail pressure limp. In 10K miles of service at 15mpg, using the observation above, the filter could have as much as 1.5 CUPS of water trapped and then frozen into the filter!!! That should have been more than enough water at the bottom of the filter housing to float the switch, illuminating the WIF lamp - but I've never seen that happen in any Duramax truck, over 6 Minnesota winters and 6 Duramax trucks! I have changed about 6-8 frozen and plugged fuel filters, however... :mad: ...about one per season during the typical January cold snap.

Quote:

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Originally Posted by npauli

Has anybody ever tried aftermarket FWS? I'm beginning to wonder if water is playing a role in some of the fuel system problems I'm now scared of.

Evidence:
1) Sounds like our factory FWS and sensor doesn't catch much.
2) The last filter revision sounds like it's more focused on removal of water than particles
3) Reports of rust in fuel lines when injectors are replaced.

There's some aftermarket FWS options for commercial trucks. I'm tempted to try one with a clear bowl to see what it catches, but don't want to waste $ if somebody's already ruled that out.

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1) The sensor isn't the issue. The water is going to pass through unless it's a BIG slug. This is why I treat with FPPF which is an emulsifier. Water all gone...
2) They keep redesigning this filter and it's getting sickening. It's just too hard to trap the water especially on a vibrating engine with substantial flow rates and air on the filter.
3) This is the LB7 and it is not related to water in the fuel it's from water and junk running inside the line nut. This is on the exterior of the line until removed. Internal rust would be from guess what- demulsified water. Emulsify it and lock it up in man-man defense...


In IL I would expect LOTS of issues with fuel in winter as they are running bio in the 5-20% range and it's just going to be a problem...

http://www.boatersworld.com/product/..._source=google

JK - what do you think of plumbing something like this in, before the factory filtration, to take out the water?