300 Tdi single fuel line

Hi all,

I'm replacing the fuel tank on my 110 300 Tdi (originally a MOD LHD 2.5 N/A diesel), and was sent a fuel tank without a hole on the top, even though I ordered one with the hole on top to match the leaking one. While grumbling about it and taking the return line off the top, I notice the return line is bone dry. Tracing the return line back to the engine compartment, I see the return line is plugged off.

I did not do this conversion, but I was told that my 300 Tdi was one of the last ones that were made (2002-2003?). At some point late in the 300 Tdi line, especially for ROW, did they switch to a single fuel line setup? Or is this just a bad install? The engine has about 44,000 miles, and seems to run fine.

Thanks.

bad install leak off from injectors still going to pump?

I don't see any leaks in the engine bay, only my leaking fuel tank. The return line appears to go to the fuel filter housing rather than the fuel pump. There are two lines attached to the fuel injection pump, one in the front and one in the rear. Both go to fittings on the fuel filter.

The fuel filter has three fittings (versus two that I see in a '96 manual I've downloaded). Two of these fittings go to the fuel injection pump, and the third goes to the fuel lift pump.

I now understand what's been done here: the return line goes to the filter rather than the tank. Is there any down side to running it like this? Off the top of my head, it seems OK - the fuel lift pump would already have to exceed the capacity of the fuel injection pump to prevent starvation, so what's a little less fuel pumped up? Or would there be too much pressure at the fuel filter, preventing proper operation? I would expect to see leaks if this was the case. Admittedly, the engine area is not bone dry, but I would expect something to see and possibly smell very noticeable if things were leaking.

Thanks.

the only draw back is any air getting in cant self bleed ,in that its going back to filter and so round to pump again not to tank and out of system

Thanks. This is my first diesel. I know that air in the fuel system is not good, but will any air eventually work its way out of the system through the injectors if the motor is running? I've replaced the fuel filter recently and I did not encounter any problems starting. And the filter was also replaced just before I bought in last October.

It will self bleed i used to know a man who made just this set up for trucks to run on other types of diesel! and this was how he overcame the problem of the other diesel getting into the main tank
Ive seen quite a few diesel cars were the return line goes into the main feed to the inj pump.


Lynall

So it's decided - it stays as-is. Good - it's not like I needed something else to work on. It'd be nice to actually drive it every once in a while.