Where's the Water Coming From?

[rs899]

I don't expect anyone can answer this, maybe I am just venting...

A few months ago my Jetta started running poorly and I changed the filter and found a LOT of water at the bottom.

I dropped the tank and cleaned it out.  I even spent some time RTVing the surge valve ( or whatever all that stuff is at the top of the filler) before I put it back in.  I built a shield out of sheet metal to deflect water from splashing from the rear tire onto that area of the tank.  I disconnected the factory water separator.

I put a clear Mercedes pre-filter in-line before the VW MK1 filter I use in the car.
Now I am catching a thimble-full of water every week in the prefilter and in the bottom of the MK1 filter.  Car seems to be running OK, so maybe I am catching all of it....

Where the H is is coming from?

[CRSMP5]

mk1 do not have factory water seperator..

top of filler neck rotted out?? common thing....

[R.O.R-2.0]

mk1 do not have factory water seperator..

top of filler neck rotted out?? common thing....

i was gonna say it was a rotten filler neck, or a bad gasket on the fuel cap..

maybe even a broken/cracked hose in the wheel well..

[rs899]

Sorry, no,  this is on my '91 Jetta Mk2 with a plastic tank.  I made a point of carefully looking over all the access areas on the tank where water could be getting in when I dropped it.  I thought I found a bad seal and plastered it inside and out with RTV.

I use a MK1 filter on a Mk1 spin on holder slipped into the Mk2 filter holder.

I suppose it could be condensation or bad fuel, but I never see this kind of issue on my Rabbit pickup or any of my Benzes

[guy plain]

 i know in my dads dodge we bought fuel and it was loaded with water.... took forever to work it out of the system......had to drain the filter twice a week for a month....it was a real pain in the a$$ .... but when a fuel station gets low on fuel...near the bottom of the tank... water can be pumped into you car.... the crapy thing is you may have payed for that water lol i know we did.

[bajacalal]

i know in my dads dodge we bought fuel and it was loaded with water.... took forever to work it out of the system......had to drain the filter twice a week for a month....it was a real pain in the a$$ .... but when a fuel station gets low on fuel...near the bottom of the tank... water can be pumped into you car.... the crapy thing is you may have payed for that water lol i know we did.

I find this hard to believe.

The fuel pickup is in a fixed location inside the tank, so it should always get fuel from the same location, regardless of the fuel level. And water always sinks to the bottom of the fuel, so it will always be down there. It works the same way for automobiles- the old adage that if you run your tank lower than 1/4, you pick up "the dirty fuel" is crap, the fuel always comes from the same part of the tank. Running out of fuel can damage your fuel pump though...

Anyway, I do agree that it comes from the fuel and is usually the fault of the fuel station and their poor maintenance practices. Either their tank is faulty or they have not maintained their filters, the fuel pumps themselves are supposed to have filters.

[maxfax]

Where's the tank vent on a MK2??

[Patrick]

Don't buy your fuel when you see the truck pumping into the station, whatever is in the tank will be stirred up for the pumps to put in your tank. Wait at least a few hours or go down the road to the next station.

[guy plain]

I find this hard to believe.

The fuel pickup is in a fixed location inside the tank, so it should always get fuel from the same location, regardless of the fuel level. And water always sinks to the bottom of the fuel, so it will always be down there. It works the same way for automobiles- the old adage that if you run your tank lower than 1/4, you pick up "the dirty fuel" is crap, the fuel always comes from the same part of the tank. Running out of fuel can damage your fuel pump though...

Anyway, I do agree that it comes from the fuel and is usually the fault of the fuel station and their poor maintenance practices. Either their tank is faulty or they have not maintained their filters, the fuel pumps themselves are supposed to have filters. 
 
 
 
 i was talking about fuel from the gas station ....not the fuel in the car lol ....... theyer suposed to dip there fuel and use this paste that tells if theres water in it.... but alot of places seem to skip that.... so the water can build up in the holding tanks...and we get to pay for it lol

[rs899]

I have to believe I am picking this crap up from the filling station at this point.  It really hasn't rained enough to account for anything getting in while driving.  Problem is, I have bought fuel from 2 or 3 sources, but one most often.  But that's the place I have been buying for the other cars, too, and they haven't been plagued by this.

Just FYI, the fuel pickup on the Mk2 is literally at the bottom of the tank.  The fuel is sucked up through the gauge sending unit, which is designed with a sliding pickup that sits waaaay down there.

[R.O.R-2.0]

I have to believe I am picking this crap up from the filling station at this point.  It really hasn't rained enough to account for anything getting in while driving.  Problem is, I have bought fuel from 2 or 3 sources, but one most often.  But that's the place I have been buying for the other cars, too, and they haven't been plagued by this.

Just FYI, the fuel pickup on the Mk2 is literally at the bottom of the tank.  The fuel is sucked up through the gauge sending unit, which is designed with a sliding pickup that sits waaaay down there.

the pickup unit is spring loaded. it keeps tension on the lift pump, and the screen on the bottom of the lift pump.. it literally draws from within an 1/8th of an inch from the bottom of the tank.. the spring pushes everything against the tank to keep everything tensioned..

(this is assuming its mk2/3)