Diesel leak

Raymie

Member
to me 50mpg seems low - when I first got mine it was doing just above 50 (not sure what now the weather has changed) and I found out that the fuel cooler under the car was leaking (through the metal), so as I drove v small drops of fuel would drip on the road / it was not that obvious - now that it's fix I get about 60mpg which still does not seem that good as I get 45mpg out of my big 5 series BMW (2002 2.5L )
I've been bothered by a small diesel leak somewhere on my car as I can smell it and now that the undertray has been removed for a few weeks there is a tell tale patch on the drive, I will now have a close look around the engine bay (I didn't know there was a fuel cooler on a 75TDi ? )
 
I've been bothered by a small diesel leak somewhere on my car as I can smell it and now that the undertray has been removed for a few weeks there is a tell tale patch on the drive, I will now have a close look around the engine bay (I didn't know there was a fuel cooler on a 75TDi ? )
Start a fresh thread perhaps for clear help. [Edit - @Proghound: These two posts moved from original TDI90 economy thread]

That said inspect the tandem pump underside area. It's located on the right side of the head with several pipes attached. Lots and lots on here about it. Inspect all rubber hoses and clean thoroughly as diesel will soften and eat them. Then your looking at new coolant hoses too
 
When the fuel pump went on mine the diesel was pooling on top of the subframe; when reversing off the drive it would start to drip and when the brakes applied the whole puddle would cascade off onto the ground in one spot. Had to replace a couple of coolant pipes but was lucky. That was the second diesel leak I encountered - the fuel filter casing disintegrated early on ; the third was the fuel cooler under the driver side passenger footwell.
 
When the fuel pump went on mine the diesel was pooling on top of the subframe; when reversing off the drive it would start to drip and when the brakes applied the whole puddle would cascade off onto the ground in one spot. Had to replace a couple of coolant pipes but was lucky. That was the second diesel leak I encountered - the fuel filter casing disintegrated early on ; the third was the fuel cooler under the driver side passenger footwell.
Hi Robin,
It sounds like you've had your full quota of diesel leaks ! Thanks for sharing your experience.

The metal fuel pipes have always looked wet on my car all the way over to the (water trap ?) canister in LH corner under the headlight so i'll have to dry them all first then re-inspect.

I remember once watching a diesel technician use chalk dust to help find the source of a leak on a Perkins marine engine. Hopefullly i'll get a clear diagnosis of where the source is .
 
Are we talking about the same pipes? The fuel pipes come out of the pump and run as a pair along the front of the engine underneath the sound-deadening cover, then around the driver's side of the engine and down the bulkhead ; there are a pair of metal pipes in mid air between the diesel pump and the coolant reservoir / behind the ABS unit pipework that are almost always covered in condensation when the car is running / has recently run - that are the pipes containing the aircon gas from the compressor to the aircon unit in the nether regions behind the glovebox/central console area.
 
Hi Robin,
Thanks for response.
To clarify ; there appears to be signs of fuel leaking somewhere down the LHS of the engine i.e. the flywheel end.

You are right, the wet metal pipe I was referring to is not a fuel pipe but actually an oil pipe running to the oil filter housing.

On the sample image beneath I see the fuel pipes at the top that you referred to.
diesel_motor.png

Hope to get back later with an actual pic of my engine bay.
Regards,
Raymie
 
Looks like the tandem pump is leaking diesel. If so it is critical this is repaired as soon as possible. The leaking diesel will destroy all rubber pipes it comes in contact with and becomes expensive rapidly.
 
I think you should ask Paul @depronman for one of his spacers so you can replace the part wholesale with the more commonly available / better engineered Bosch tandem pump.
 
Concur completely with both @audifan and @dj_efk points made above - in that location the diesel running down the oil pipe can only be coming from the pump, and the Bosch pump is much more reliable than the LUK alternative; unfortunately as mentioned above the Bosch fouls the EGR / ASV complex on right-hand-drive BHC / ATL cars unless you get an extra spacer that @depronman has engineered that gives the clearance needed to fit the Bosch pump to these engines. It needs to be done pretty rapidly as diesel is toxic to the rubber parts down there.
 
After removing the sound deadening pad this afternoon, I took a few pics around the pump.

The fluid I am now more concerned about is oil rather than fuel - see image of EGR connections.

I've cleaned up the metal pipe at the filter so will monitor for any future signs of diesel collecting on it....

Engine runs fine so I have no typical fuel pump symptoms of starting issues and long cranking .
 

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You may have more than one leak there. The ones to go for first are the ones that drip onto cooling pipes. Diesel balloons them qickly and they are NLA.
Look long and hard a the tandem pump. Is it a LUK?
 
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Nearly all tandems were LUK from factory, but looking at the engine I would say it is a tdi 75 AMF engine which would take a Bosch replacement tandem without any extra spacer needed.

For an oil leak in that area there are five possible candidates.

The tandem pump gasket.
The EGR valve.
The rocker cover gasket.
The oil cap.
The breather line.
 
Could anyone also help identify where the cam sensor is located ?

- Definite witness mark from the rocker cover in the front corner.
- The EGR is positively glistening with an oil film (does the internal diaphragm fail on these as there is a small breather hole on side ? )
 
Opposite end of the engine behind the cam belt. The cable for it runs across the front of the block.

Rocker cover gasket is quite common especially if not replaced and torqued correctly. EGR cheap enough just to replace it. Diaphragm not usual to fail but build up of gunk inside the valve finds its way out through the breather hole.
 
Thoroughly clean off as much leaked fluids and then you will have a better chance of determining exactly what and where the leaks are. Will also make the job of working on the area far more pleasant when you need to.
 
Nearly all tandems were LUK from factory, but looking at the engine I would say it is a tdi 75 AMF engine which would take a Bosch replacement tandem without any extra spacer needed.

For an oil leak in that area there are five possible candidates.

The tandem pump gasket.
The EGR valve.
The rocker cover gasket.
The oil cap.
The breather line.
Yeah, sticker in service manual confirms engine is AMF
 
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