[Fishman002]

I have an opportunity to purchase a 1999 TDI beetle with 132K showing. The seller says it has a fuel leak "up front in the engine area". The battery is low so I have not been able to start it even after a jump. It just spins but no smoke or fire. The car ahs new tires, brakes, timing belt, water pump, headliner and door panels. She is asking 3300 but I have her down to $2400 (provided it will start). What could be the cause of the fuel leak and what are the cost of the repair?

 

[PRM502STREET]

That is really low miles for a TDI. & a good price too!

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[tedybear]

Without starting it, or at least getting the fuel pump to prime the system--to many things it could be. Is it leaving a puddle under the car? If you look under the car, does anything look "Washed" or discolored with fuel?

I do not have the TDI myself. But I wouldn't mind finding one up my way It's a fair price, but a huge unknown.

S-

 

[janitz]

That is really low miles for a TDI. & a good price too!

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So your first thought should be, "This is too good to be true."

And your second thought should be, "Because it likely isn't."

 

[janitz]

But anyway, I bet I know why it won't start and where the fuel leak is most likely.

The fuel filter is likely the problem. If they changed it themselves but didn't replace the O-rings properly it could start leaking and allow air into the system. If the vehicle sat for a while then it would replace all the fuel up top with air as it slowly leaks out.

The 1999 ALH engine doesn't have a lift pump in the fuel tank, it relies entirely on the fuel pump in the engine bay to create flow. If air is allowed in the system it will lock up the flow of fuel and the engine will crank but never start.

You'll also get that happening if the fuel tank was allowed to run empty. So all you old Beetle TDI owners, never let your fuel run out or you will need a tow as the engine will almost certainly not start until the air is evacuated.

What I would do with this vehicle to get it started would get a hand vacuum pump and small hose, hook it up to the return line from the fuel filter and pump until I see fuel and no air bubbles. That will pull the fuel through the filter, remove all air in the filter and also pull the fuel through the pump and remove any air there.

The return is the line going to the back of the car from the plastic T fitting on the fuel filter. Pull the existing hose off the T and attach the vacuum pump hose in its place. Pump only a little and let it run, don't go crazy or you'll have fuel everywhere all the sudden.

 

[Fishman002]

But anyway, I bet I know why it won't start and where the fuel leak is most likely.

The fuel filter is likely the problem. If they changed it themselves but didn't replace the O-rings properly it could start leaking and allow air into the system. If the vehicle sat for a while then it would replace all the fuel up top with air as it slowly leaks out.

The 1999 ALH engine doesn't have a lift pump in the fuel tank, it relies entirely on the fuel pump in the engine bay to create flow. If air is allowed in the system it will lock up the flow of fuel and the engine will crank but never start.

You'll also get that happening if the fuel tank was allowed to run empty. So all you old Beetle TDI owners, never let your fuel run out or you will need a tow as the engine will almost certainly not start until the air is evacuated.

What I would do with this vehicle to get it started would get a hand vacuum pump and small hose, hook it up to the return line from the fuel filter and pump until I see fuel and no air bubbles. That will pull the fuel through the filter, remove all air in the filter and also pull the fuel through the pump and remove any air there.

The return is the line going to the back of the car from the plastic T fitting on the fuel filter. Pull the existing hose off the T and attach the vacuum pump hose in its place. Pump only a little and let it run, don't go crazy or you'll have fuel everywhere all the sudden.

Thanks for the help all of you guys. You all are great. Here is an update. I was given permission to remove the battery by the owner and charge it. It was 36% when I started and 100% three hours later. I put the battery back in hoping for a start but no luck. So I dug a little deeper. I loosened each of the fuel lines and cranked the engine to see if there was fuel flowing. The fittings were wet but not exactly flooded with fuel. The owner told me that there is a leak "somewhere" up front in the engine compartment. I suspect that the fuel pump is where the leak is but can't really tell without the engine running. I then tried a spot of ether after disconnecting the glow plugs and that got it to turn over faster and the smell of diesel exhaust became evident but it would really never "fire". I called the local VW shop (which I trust as regard reputable) and spoke with a tech and he pretty much told me the same thing you guys did, that I needed to pull vacuum on the return line and refill the filter and pump . So, weather permitting tomorrow I am going to try and reprime the fuel system. After doing some reading on this forum I realized that this is the same engine that I had in my 1985 VW Golf so I have some history with it.

 

[Smileybug]

Be careful using ether. It shouldn't be used on a diesel at all.

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[Fishman002]

Be careful using ether. It shouldn't be used on a diesel at all.

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Yes I know. I have an F-350 7.3 PSD and an F-750 with a Cummins. It is OK if you disable the glow plugs and take it very easy.

UPDATE: Tried to prime the pump today outside in 30 MPH winds, snow, and 19 degrees. Got to want it bad to do repairs in those conditions. Anyway, fuel pulled all the way through to the vacuum pump but the car still would not start. I think I am going to let this one pass. That little voice is talking to me. After all they made several million of these and there will be another one along soon.

 

[janitz]

Good choice.

 

[Fishman002]

Well I pulled the trigger on the car and it turned out to be a leaky fuel pump at the fuel volumizer and a bad fuel filter check valve. Car runs like a top now.