Clattery when cold
Join Date: Feb 2012
Location: United Kingdom
County: Greater London
There is no fuel line front O/S/F. Are you sure it is not engine oil? The oil cooler is located just in front of the O/S wheel, and a common disaster area thanks to corrosion of the pipes/unions/cooler itself. Check the dipstick to make sure oil level is still correct/that you have oil.
If it is DERV (and I hope it is) then it can only be running down from the top of the engine. A common problem is the fuel return lines from the injectors - which are rubber hoses, with plastic connectors, that recirculate excess fuel to the filter. Pennies to repair with new, but leaks in those wouldn't stop the motor running, just spray diesel everywhere.
The high-pressure fuel pump is the black lump attached to the large bracket behind the cylinder head, offside, between head and bulkhead. It is powered from the cambelt. It's fed by a pipe from the fuel filter, and the filter is a common source of leaks. Leaks there are under pressure from the lift pump at the tank, and pressure loss can mean the HP fuel pump can't work - it needs inlet pressure. However, a leaky low-pressure side probably won't plaster the top of the engine in fuel. That's more likely to be a problem with the metal HP pipes that run from the HP pump to the common rail distribution manifold, and then to the individual injectors. Fuel on the HP side is under dangerously high pressure and will find any pinhole or leak and be ejected all over the place. That pressure loss will also mean the injectors are not being fed so the car won't run.
So I think you are looking for a damaged pipe or loose union on the HP side. Be very, very careful working this. It's fine with the engine off (zero pressure), but with the HP pump operating (ie engine turning over), fuel should be at 21,000psi and is potentially fatal if injected through skin. Gloves won't help. Do not touch any area you suspect of leaking and wear eye protection and don't put any part of yourself close to the system. If there is a leak, it will probably be pretty obvious. Confirm by placing paper towel near the origin to catch spray.