94 2.5 Master T35D Leaking Diesel - Dwimorberg
Hi there, I don't know if anyone can help me but I've a 1994 Renault Master T35D camper van with a non-turbo 2.5 diesel engine. Recently it's been getting air in the fuel system to the point that I can't start it from cold without first priming the fuel filter by pressing the plunger pump around 30 times. After that it starts ok.

Last weekend while on a cycling trip I noticed fuel dripping out from under the engine. It's not much, just a couple of drips every 10 seconds or so, and it goes away shortly after the engine's stopped. Looking underneath isn't very helpful because the diesel is everywhere but it's mainly (when stationary) coming off the oil filter (definitely not oil!) and from what I assume is the fuel injector system, above where the throttle arm is.

Looking at the engine from the top, there's no sign of leakage; it seems to be happening roughly halfway down the engine downwards.

When the van is started from cold the leak doesn't appear if it's left to warm up gently, only appearing when having been driven for a mile or two (I assume the action of revving the engine and changing gear has something to do with it).

Is anyone familiar with these engines or this problem? As far as I can see there's no breaks in the pipe although it's almost impossible to see down the side from the top or underneath as the engine's mounted in the middle.

If there's any detail I've missed, let me know!

Many thanks in advance,
94 2.5 Master T35D Leaking Diesel - Javalin

at a guess - and it is a bit of a guess....

They are mechanically fuel injected (as opposed to electrical injectors on more modern diesels) and there is an assembly under the throttle cable which does all that. The leak might be in there.

Have you taken the top black cover off where the oil fillter cap is - you can see the injectors there from memory - maybe you've a broken pipe / leaking injector. A leak here might well end up on the oil filter which is nearby and below.

So I hear - mechanical fuel injection is right pig to do stuff with....

Find a nice garage (who know about mechanical diesel injection) and get a quote for investigation and repair. Or a commercials (vans etc) servicing place might be better?

94 2.5 Master T35D Leaking Diesel - Dwimorberg
Hi James, many thanks for your reply!

I've found the culprit, thanks to your suggestion. I took off the black cover and had a look at the injectors, one of which had some diesel around it. As I was tightening it up (it's fine now!) I dropped my spanner down the side of the throttle body; shoved my hand down to get it and caught what I assume is the diesel return pipe (a rubber pipe that joins a metal pipe that's attached to every injector). As I caught it it just fell in half and lots of fuel went everywhere.

So, I'll be down the motor factors tomorrow for a new 4" length of pipe and then I'll be laughing next weekend :D

Thanks hugely for your help, it's saved me a potentially big garage bill! If you're ever up near Hadrian's Wall there's a cup of tea in it for you ;)