I have a simple question, does anyone know how (or if it’s even possible) to drain water from the factory fuel filter on a Duramax? A friend of mine (drives a Furd) after a recent heavy rainstorm told me he had water in his fuel after filling up from the same station I frequent. He’s taken his truck to the dealer for service, I have yet to see a WIF message on my DIC but am obviously worried. The owners manual was of little use (doesn’t even seem to pertain to the Diesel).<?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
I may simply change the fuel filter just to be safe (only have 2300 miles on the truck) but if I can drain water I would like to know how.

By the way I tried the search feature, but he search button is greyed out???

Thanks in advance for the advise.

The big owner manual is pretty generic. You should have received a little book which is the Duramax and diesel addendum to the reqular owner manual. It gives pretty good instr. on draining water from the fuel filter.

Thanks for the reply aka108,


Hmmm, didn't receive any addendum, yes the owner's manual is very generic... not helpful at all. I'll have to contact my dealer to see about getting this addendum. Does it have a part number, or anything I can tell the dealer so I won't get that deer in the headlight look from em?


Thankfully from your post it sounds as though I can drain water from my fuel. I'd like to do this as I'm suspicious my fuel may have water in it, however without this addendum I'm shootin in the dark. Is this a complicated procedure, or just a few steps that could be posted?

You need to contact your dealer on the book that you should have got, there is alot of important info in there that you should know. Its pretty hard to tell you how to do it as the book has pictures to show you what part or piece your looking at. If the dealer doesnt know what your talking about, tell them you want to see another duramax on the lot and see if one of those trucks have the book in it. The book is white with little brown squares on the left side and says Duramax Diesel with Chevrolet, Gmc in the lower left hand corner. It has your maintance schedule in it also. Edited by: 96vette

Yes, you can drain the fuel filter on a Duramax. The only thing making it difficult is getting access to the bottom of the filter.

There is a screw-on nylon circular part about 2 inches in diameter attached to the bottom of the metal fuel filter can. This is the water accumulator. There is a tip on the end of this part that is the drain tube. The tube is about 3/8 of an inch in diameter. You should be able to feel something that is similar to a wing nut on each side of the drain tube located on the very end of filter assembly.

Just turn the wing nut as if you are unscrewing a light bulb. This will open the drain valve and drain the fuel or water in the bottom of the filter. Tighten when done. It may take several turns to open the valve.

The filter appears to have a vacuum in it that prevents the fuel from draining when first opening the valve. Push down on the primer pump a few times. It is mounted on top of the filter housing. This will pump fuel out of the filter through the drain tube. (I think you can also open the bleeder screw, but I suspect the primer pump make it easier to limit or control the amount of fuel being drained.) You do not need to drain the entire filter when checking for water.

I put a folded newspaper on top of the frame rail, under the filter, to keep fuel from dripping on the frame. The fuel will remove the coating off the frame rail.

I use a tin can, placed under the drain tube, to capture the fuel. I punched a hole near the top of the can with a string attached, which I then tie to a tube above the filter housing. This is just a precaution from making a mess in case I drop the can.

Put the drained fuel in a glass jar then look for any water.

The biggest problem I had was getting the valve loose the first time. There is not much room in there to get a good grip. I ultimately dropped the wheel liner and then it was easy. Now that it is loose, I can open it from above without any problem. Just don't over tighten when closing the valve.

Eric posted an excellent write-up in the Do It Yourself topic that may be of help. The title of the posting is "Fuel Filter replacement pics/instructions". It has some great photos of the water accumlator attached to the bottom of the filter.

Good Luck. Edited by: BH in AZ

Thanks for the responses, this forum rocks! http://dieselplace.com/forum/smileys/Rock%20On.gif<?:namespace prefix = v ns = "urn:schemas-microsoft-com:vml" /></v:stroke></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:ulas></v:path><?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:lock aspectratio="t" v:ext="edit"></o:lock></v:shape>


I've contacted my dealer and they apologized profusely for not having the Duramax supplement in the vehicle when I picked it up, I will be getting this little gem this afternoon right after I drain my fuel filter to check for water.


Thanks again.