Diesel leak related to the Fuel burning Heater

[johnnyb44]

Hi and hope your all well,
I've noticed a few weeks back that my diesel 75 has become a little incontinent.
The small diesel cooler/radiator just behind the driver side rear wheel has developed an anoying leak. After having a good look around it appears to be coming from either the pipe work or the junction box these pipes go into which I believe to be a diesel thermostat of some sort.
I've also noticed it only leaks when the Webasto fuel burning Heater is running.So for the time being I've pulled the plug on the FBH to temporary stop the leak.looking around the Internet, the coolers seem to be like hen's teeth and the breakers yard have very little in stock of 75s.If anybody could point me towards either a replacement or a fix towards this I would be very grateful.
Hope you have a great Christmas and stay safe in these yet again uncertain times,
Best Regards,
Johnny

[macafee2]

pm mickyboy a dealer here, he may be able to do you a second hand one.

Macafee2

[johnnyb44]

Many thanks Macafee2. It's certainly something I want to get sorted..Im sorting/investigating some strange noises over the Christmas break.Once I've replaced some worn bushes causing it, I will concentrate on sorting the diesel cooler out.
This year my car has really kept me on my toes with issues.Its my daily driver car and depend on it for work ,but have been finding it difficult sometimes sourcing part's for it.
It's the silly things that are hard to get hold of nowadays.Earlier this year I had great fun tracking down a passenger air bag sensor for my MK1 75. Luckly Jules came to the rescue with a second hand one.
Actually thinking of Jules I might give him a call to see if he's got a second hand diesel cooler.

[Mike Noc]

The FBH fuel supply is separate from the LP delivery circuit which has the fuel cooler. There is a small pipe coming out of the top of the offside tank module which goes to a small pump situated under the car just forward of the rear seat. From there a pipe runs to the FBH.

[Southern Star]

When this happened to mine I just bypassed the whole lot with a length of fuel pipe. I don't know if there is some reason who you shouldn't do this but that was four or five years ago and I haven't noticed any detrimental effects.

[Devilish]

Originally Posted by Mike Noc

The FBH fuel supply is separate from the LP delivery circuit which has the fuel cooler. There is a small pipe coming out of the top of the offside tank module which goes to a small pump situated under the car just forward of the rear seat. From there a pipe runs to the FBH.

Correct, this is the cause of the fuel leak. I have found it to be a pin hole in the fuel line, and corroded spring type clamps on the rubber link hoses

[HarryM1BYT]

Originally Posted by Southern Star

When this happened to mine I just bypassed the whole lot with a length of fuel pipe. I don't know if there is some reason who you shouldn't do this but that was four or five years ago and I haven't noticed any detrimental effects.

If you bypassed the FBH pump, the the FBH will not work at all. It's a 'metering/dosing pump' or solenoid pump. It injects a dose of diesel with each click it makes. The are a common point of failure in that they are quite exposed and rust away.

[johnnyb44]

Many thanks for the great advice.Since disconnecting the plug to the FBH the leak has completely stopped.
I'm not very mechanically minded, but I do like to try and sort and understand the problems my car throws at me.
In a "nut shell" from what ive read,it's most likely not the fuel cooler that's failed but more likely a leaking feed pipe that solely feeds the FBH.To access this pipe do I need to drop the fuel tank or is it easily accessible with it in place.
Sorry for all dumb questions but it may help others as well as me to tackle the job.
Kind Regards

[HarryM1BYT]

Originally Posted by johnnyb44

Many thanks for the great advice.Since disconnecting the plug to the FBH the leak has completely stopped.
I'm not very mechanically minded, but I do like to try and sort and understand the problems my car throws at me.
In a "nut shell" from what ive read,it's most likely not the fuel cooler that's failed but more likely a leaking feed pipe that solely feeds the FBH.To access this pipe do I need to drop the fuel tank or is it easily accessible with it in place.
Sorry for all dumb questions but it may help others as well as me to tackle the job.
Kind Regards

It's really easy. Just look under the off-side/ driver's side, the rear door. You can reach under the car without jacking it up to inspect, but it will need raising to replace it.



There is a rubber mounted cylindrical rusty object, with two pipes and a cable plugged into it - that is the dosing pump. One pipes goes into the tank, the other all the way to the FBH. Likely that unit has rusted to the point of leaking

[johnnyb44]

Much appreciated taking the time to explain.This weekend I'll take a sneaky look at this.The drip though has been coming from the fuel cooler area.In fact the diesel was dripping off the cooler but after having a closer look it appeared to be dripping above it and then running down the cooler.As said before it's since stopped after disconnecting the FBH.As from the good advice given I can only assume the FBH supply pipe must be routed somewhere in this area.