XSeries-forum

I have a diesel leak. It's not coming from anywhere noticeable but there is a constant drip of clean diesel running off the bottom of the bell housing. None of the pipes are leaking. Nor are the diesel heater or fuel filter.

Any one any ideas?

Kerry

What about the fuel rail and injector area? You will probably need to take the sound shield/cover off the top of the engine to be able to see down onto that area. It's only a few Allen bolts to unscrew and the oil cap to be taken off and it lifts away.

my first guess would be an injector seal gone. hope its a cheap problem anyway!

The location makes me suspicious that it might be gearbox fluid, Are you absolutely sure it's diesel ?
The long life Gearbox oil that X5 use is not pink, It is much more a clear liquid then conventional ATF

Defiantly diesel! I know this because of the blue tint to it! Also the fact it only drips when the engine is running! No loss of power at all! Makes me think it is a return pipe!

Had all the top covers off and no signs of and leaks from the injectors!

UK Diesel fuel is either coloured with Solvent Yellow for road use (legal requirement since 2002), or Red for non-road/agricultural use. All the legal diesel I have seen is sort of wee/straw coloured, not blue.

Blue to me says Coolant or screen wash, or possibly transmission. Not sure I have ever seen blue diesel fuel..yet. It would be unusual to see that strong a colour in a drip though. Are you absolutely sure it's fuel? Not trying to be silly, but something doesn't add up with the blue colour you are reporting - which would also explain the lack of any leak being apparent on the fuel system.

What does it smell like? Does it feel slippy? What does it taste like? If its sweet it'll be coolant.

Sounds more like coolant to me due to colour. Unless you smell the diesel it won't be fuel.

Right after a bit more investigation.

1. Slight diesel leak on fuel filter.
2. Seems to be a small puddle of diesel around last injector but no signs of it actually coming from the injector.
3. Coolant is also leaking but cannot see where from!

Any one got any more ideas.

Kerry

So I've solved the diesel leak. Appeared to be a faulty seal on the fuel filter.

However I still have the leaking coolant. I have replaced the top hose and adaptor but still no visible sign of coolant leaking but there is a drip constantly when engine is running.

Are there any hoses that run round the back of the engine? I have checked all visible pipes to no avail!

Many thanks for your help!

Kerry

There are three hoses that run into the firewall at the back right of the engine. They feed the heater radiator matrix. You may need to remove the microfilter assembly to get at them. Not having mine any more I can't remember how visible they are.

Front engine cover removed & Microfilter assembly fitted:

Assembly Removed and the three hoses are above the right hand yellow circle in this image:

I have checked those 3 pipes. Bone dry!

Any other suggestions!

Kerry

It was worth a try. Any sign of any seepage down the back of the engine? How fast are you losing coolant?

Any sign of steam from the engine when it's running? Any odd smells in the cab when the heating is on or turned up? I'm also assuming your pollen filter and a/c system is clean so would not generate an odd smell.

If there's nothing on the hoses hot or cold and no obvious leaks except on or around the engine all I can think of is a gasket somewhere but not having an engine to look at now I'm out of ideas. The usual suspects being hoses, clips, expansion bottles, thermostat housing, water pump, air con, heaters, rads and head gaskets. Most of these are at the other end of the engine, and the ones at the back have no sign of seepage. Apart from the above, i'm out of ideas for now.

When i have the car up on the ramp the coolant appears to be coming from the bell housing. I track my hands round then its dry. Cannot for the life of me find where it is leaking from!

Kerry

Transmission fluid should be pink (at least all the ATF I've seen is), but is yours blue? Any sign of mayonnaise in the engine oil?

Assuming it's coolant and not transmission fluid then if you can see down the back of the engine with a small mirror that might find the leak area. See if it's around the break between block and head - which hopefully it isn't - or running down from somewhere higher.