Fuel Filter Drain

So I figured out yesterday that the fuel filter housing on my 2011 Jetta does not have a drain. I have been driving diesel pickup trucks since 1999 and every truck I have owned has had drain on the filter housing that served 2 purposes. First to drain water from the filter (a monthly maintenance item) and to drain the filter housing to facilitate changing the filter. I guess we are supposed to just "buy fuel from a reputable dealer" and hope we never get water in the fuel? Kinda like sticking our heads in the sand isn't it? Now if our very expensive HPFP and CR injectors bite the dust I am sure they will check the fuel out and deny a warranty claim if water is detected. So what is a "mother" to do to protect his investment?

Please note the above contains some sarcasm.

You drain the filter housing when you change the filter. (20,000 miles) The last VW car in NA to have an actual drain at the bottom of the filter housing was an Mk IV in 2005, I think, although some old parts may have been installed on the 2005.5 early Mk V bodied cars.

I use Power Service fuel additives....

Bill

The drains were there from the old days (think about my 1976 Diesel Rabbit) when getting large amounts of water mix with the fuel, was not uncommon. The over the road trucks had/have good onboard separators and may still have them, but the fuel industry has cleaned up their act and water contaminated fuel is rare today. You don't need the drain.

To be honest, I haven't ever drained anything out of my fuel filter housing and haven't experienced any water contamination thus far. Granted, I buy my fuel from pretty much the same station and always use additive.

I don't think many vehicles from present day need it any more. Though I do have to say that I wish our cars came with the hand primer on my 2004 DMax that allows you to hand pump your FF full of fuel without needing a MightyVac.

Even though I have not found water in my Dodge water separator I used to find it in my Ford truck's all the time. I was traveling the entire state back then as opposed to just a portion of the state like I do now. I still believe that a water separator with drain is an important item to have on a diesel vehicle. I guess I'll have to try and fit an aftermarket filter head somewhere before the factory filter so that I can monitor and drain as I see fit. Blind faith in any industry, ESPECIALLY the oil industry is not wise in my opinion, and yes I do know about opinions........

You can easily see the bottom of the filter housing. Fuel filter gets changed every 20k miles. If you see water in there when you change the filter (it will settle at the bottom) then you know you have gotten some wet fuel.

I rarely ever see any water in the bottom of these filter housings, and I change a LOT of fuel filters. I'd not worry about it, just service the filter (and other items) as outlined in your manual.

oilhammer said:

. I'd not worry about it, just service the filter (and other items) as outlined in your manual.

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And keep good records.

When deliver a load of diesel,I stick the tanks for water and refuse to drop if I see any. The liability is huge and fines are steep.

So far, in 32 years of driving diesel cars and 6 years with a diesel tractor, no water. Had gelling once at -22 F. Had plugged fuel filter due to crud from using B5 for 3 tankfuls (well known phenomenon when switching to bio; it cleans the tank). Had wax dropout with tractor sitting in unheated garage below 10 F a couple nights.

No water though.

Every bought a water separator for the 240D. Never installed it.

Draining fuel filters

procupine14 said:

To be honest, I haven't ever drained anything out of my fuel filter housing and haven't experienced any water contamination thus far. Granted, I buy my fuel from pretty much the same station and always use additive.

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Same here! Except, I buy fuel where ever it is the cheapest!

In just over 31 years of driving VW diesels, I have probably drained less than a dozen filters........... mostly just to see "if" there was any water or other crud!

I have always changed my fuel filter prior to the winter months annually regardless of miles on it!.......... no troubles at all!

RalphVa said:

So far, in 32 years of driving diesel cars and 6 years with a diesel tractor, no water. Had gelling once at -22 F. snip...snip.

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Hey ralph,

Plz explain what u mean by the term "gelling." I assume this occurs at low temps...but is it merely physical, hence a reversible phenomenon? Or is there an irreversible chemical change in composition of the fuel?

Does one have to purge the fuel system in order to start the engine once this occurs?

Thx

I guess you haven't read any of the threads on gelling.

Gelling is caused by wax formation in the fuel. It coats the fuel filter and plugs off flow.

It's completely reversible. Heat melts the wax. In our case, it happened on our 220D. On that car and the 240D, the small prefilter and the main filter are very close to the engine block. The heat from the block melted the wax, as it would start and run for maybe 5 minutes before quitting a couple of times.

Application of heat to the fuel filter like from a hair dryer could melt the wax, if you're where you can plug one in.

When I had the wax dropout on my tractor, I had to siphon off the tank and then fish out the wax globs that were blocking the outlet line. This won't likely happen on a car with a pump in the tank because it will probably have a large suction screen on the pump suction. Kerosene, particularly warm kero, would have dissolved the wax.

I was a chemical engineer in my past life who worked on lube oil dewaxing. Diesel fuel is just a tad lighter weight than the oils we removed wax from.

Check out the thread I made... my fuel gelled 2 nights ago when it was -23*f. I purged the system with diesel 911 and it started up.

Thanks Ralph. It's overwhelming all of the new info I need to assimilate regarding diesels. I'll look into the threads on gelling as you suggest.