Water in my MkIV fuel. Need advice. (Is it really that big a deal?)

turbocharged798

Veteran Member
Joined
May 21, 2009
Location
Ellenville, NY
TDI
99.5 black ALH Jetta;09 Gasser Jetta
water will destroy the injectors and pump pretty quickly. Drain the water separator on the fuel filter and see what comes out.
 

wonneber

Top Post Dawg
Joined
Oct 12, 2011
Location
Monroe, NY, USA
TDI
2014 Jetta Sportwagon,2003 Jetta 261K Sold but not forgotten
The ALH doesn't have a particularly high psi fuel system, and the injectors are fairly low volume and are mechanical.
My thought is the MkIV cars are less sensitive to water than the newer tech engines/injectors of the 04 and up TDIs with high pressure systems and components.

Any merit to that logic?
I don't have my manual handy for the ALH but I recall the -old- 1.5/1.6 diesels were about 1800 PSI injection pressure (or so)
To me that's pretty high. :)

Water is not good in any diesel.
I would drain the tank, change the filter, blow out the lines, and run the injector pump from a bottle of fuel until there's no water in it.
There's a access hole under my back seat to remove the fuel pickup.
Easy way to get in there to get everything out.
 

Ol'Rattler

Top Post Dawg
Joined
Jul 3, 2007
Location
PNA
TDI
2006 BRM Jetta
Water injection is a completely different animal than water in the fuel. WI injects water into the intake air stream as a mist and does not put water through any part of the fuel system.

To expand on turbocharged798's post, water in the fuel system is a big deal. If the car is running rough, there is a good chance the water separator is full of water and can't separate water out anymore. If that's the case, you will have to drain the water out of the tank.
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
There is a valve on the bottom of the filter. Open it up, drain into a container, see if there is water. Fill the filter with #2 or a suitable additive. Also, it's not real hard to access the tank, take a look.
Diesel and water don't mix, so after the car has sat for a bit they will be in separate layers. I wouldn't try to deal with it running the engine.
 

maxmoo

Veteran Member
Joined
Jan 19, 2011
Location
Lakefield, Ontario, Canada
TDI
2000 golf, 2001 golf, 2000 beetle, 2003 wagon, 2004 golf, 2004 jetta, all diesels
Depends how much water you have in your tank.
In all likelyhood its not that much.
Remember diesel floats on water, so the water will sit in the bottom of your tank or filter....hence the drain valve on the bottom of your filter.
To be safe drain/siphon your tank, change your filter and then keep draining your filter regularily until you only get fuel.

The problem will be that underground fuel tanks at service stations may have significant water in them at certain locations....so you want to be careful not to re-introduce more water when buying fuel.
 

Nevada_TDI

Top Post Dawg
Joined
Aug 17, 2008
Location
Reno, sort of...
TDI
2001 Jetta TDI
I just went through having water in my fuel tank/fuel filter and it killed my IP. The IP does not like to run w/o lubrication and you stand a great chance of destroying the centrifugal "lift pump vanes" in your IP.
I agree with draining the filter and seeing what comes out. As long as the IP inlet line doesn't lose the fuel it has it there should be enough fuel to get the engine started again. It certainly wouldn't hurt to re-purge the fuel line by applying vacuum to the pump inlet side of the fuel filter just to be safe.

Post fix I would always be diligent about running some some of a lubricating additive whenever possible.
 
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drucifer

Veteran Member
Joined
Dec 21, 2013
Location
fredericksburg virginia
TDI
2004 jetta sw tdi pd
Look on ebay for malhe KL147D. They run 15.50 to 17.50 from various vendors. Also the last one I bought was from Advance for around 15.00 but only ship to home.

Did this water problem happen before or after the flooding?
 
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burn_your_money

Veteran Member
Joined
Oct 16, 2012
Location
Missouri
TDI
99 Beetle, 96 B4V, 05 Passat wagon
For the VW just look in the tank for water with a flashlight. It will look like globs on the bottom of the tank. In a spare container mix some diesel and water to know what to look for if you want. It's very obvious. The fuel filter is also a water seperator so check what comes out as others have mentioned. I think you're getting the cart in front of the horse a bit.
 
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