300 TDI oil leak

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Hi everyone, I have an oil leak on the rear of the sump. My original sump was pretty dinged up and bent so I replaced it and resealed with Loctite ultra black according to instructions. However I am still getting the leak in the same place. The photos show the leak after resealing and no oil in engine and somehow it still leaks. I do have the engine tilted down as I am replacing the transfer case. The engine was recently rebuilt and new main seal was installed. There are no leaks upstream, it's between sump and flywheel housing.
Is there a trick to sealing the sump? Or is there something else going on?

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I don’t actually see how you know a new seal leaks if there’s no oil in it :vb-confused2:

But are sure it is not leak of some sort from further up and just colouring itself to look like engine oil.

Look at that drip on the clutch slave🤔.

J
 
Based on smell test, it doesn't smell like much - it's not diesel or brake fluid. The engine is slightly tilted down towards the rear since I had to make room to remove the transfer case. Everything above is completely dry and clean. It looks to be some oil sheen above the sump where the engine block and flywheel housing meet.
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Based on smell test, it doesn't smell like much - it's not diesel or brake fluid. The engine is slightly tilted down towards the rear since I had to make room to remove the transfer case. Everything above is completely dry and clean. It looks to be above the sump where the engine block and flywheel housing meet.
1000017000-jpg.330636
 
Could it be that the sealent you used is not good and the stuff is busy seperating into it's base chemicals . There must be some sort of liquid mixed into the compound to enable it to flow ?

Just guessing here of course
 
Based on smell test, it doesn't smell like much - it's not diesel or brake fluid. The engine is slightly tilted down towards the rear since I had to make room to remove the transfer case. Everything above is completely dry and clean. It looks to be above the sump where the engine block and flywheel housing meet.
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That looks clear to me are you sure it isn't simply water/coolant? Coolant should be coloured and smell but has it just been filled with water? Does it feel oily when you rub it between your finger and thumb?
ALL liquids in a motor vehicle have a smell except water.
Clutching at straws a bit but could it just be condensation?
 
That looks clear to me are you sure it isn't simply water/coolant? Coolant should be coloured and smell but has it just been filled with water? Does it feel oily when you rub it between your finger and thumb?
ALL liquids in a motor vehicle have a smell except water.
Clutching at straws a bit but could it just be condensation?
It's definitely oil. It's likely clear because the oil is new. There is no coolant in engine yet. It's a fresh rebuild. My hunch is rear main leaking from the bottom behind flywheel housing, so will replace it with one of the reinforced seals and tap 2 new holes. https://www.turnerengineering.co.uk...VFS8GLNGz8WC2XXDHxwxa8zk-tmqjx3LxYSB7BojhpBH6
 
It's definitely oil. It's likely clear because the oil is new. There is no coolant in engine yet. It's a fresh rebuild. My hunch is rear main leaking from the bottom behind flywheel housing, so will replace it with one of the reinforced seals and tap 2 new holes. https://www.turnerengineering.co.uk...VFS8GLNGz8WC2XXDHxwxa8zk-tmqjx3LxYSB7BojhpBH6
So the engine has been freshly rebuilt and no one replaced the rear main seal? Or they did but it is leaking, even without being under pressure or rotational forces on it?
That seal looks a good un. Do you mean "drill and tap" 2 new holes, or simply tap out two existing ones?
Surprised it doesn't just fit with no fiddling around like that.
 
So the engine has been freshly rebuilt and no one replaced the rear main seal? Or they did but it is leaking, even without being under pressure or rotational forces on it?
That seal looks a good un. Do you mean "drill and tap" 2 new holes, or simply tap out two existing ones?
Surprised it doesn't just fit with no fiddling around like that.
The main seal was replaced but obviously leaking between engine block and flywheel housing. The logic in this thread is sound that its likely not the sump seal because there is no oil in the sump and I am very skeptical that the leak would magically fix itself. Since I already have the transfer case off, I will also drop the transmission and remove the flywheel. You are right, I mean to say drill and tap 2 holes. The 2.8 seal is reinforced and has 2 additional attachments to the block at the bottom.
 
The main seal was replaced but obviously leaking between engine block and flywheel housing. The logic in this thread is sound that its likely not the sump seal because there is no oil in the sump and I am very skeptical that the leak would magically fix itself. Since I already have the transfer case off, I will also drop the transmission and remove the flywheel. You are right, I mean to say drill and tap 2 holes. The 2.8 seal is reinforced and has more 2 additional attachments to the block.
I'd make sure first, from Turners, that the two extra holes are really necessary. Don't want to introduce further risk of possible leak spots.
Unless of course you have already done this!
 
It's definitely oil. It's likely clear because the oil is new. There is no coolant in engine yet. It's a fresh rebuild. My hunch is rear main leaking from the bottom behind flywheel housing, so will replace it with one of the reinforced seals and tap 2 new holes. https://www.turnerengineering.co.uk...VFS8GLNGz8WC2XXDHxwxa8zk-tmqjx3LxYSB7BojhpBH6

I looked at those seals too.
I will be doing mine soon but in the end I chose an OEM one.

There is a reasonable amount of sense to the MWM version, the additional fasteners (which do need drilling and tapping) are not obligatory.
The seal has additional dust sealing and (apparently according to the blurb) " the seal lip runs in the correct place on the seal journal of the crankshaft".

To be honest I don't know what that means.
Why would the OEM seal not run in the correct place ?
 
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I looked at those seals too.
I will be doing mine soon but in the end I chose an OEM one.

There is a reasonable amount of sense to the MWM version, the additional fasteners (which do need drilling and tapping) are not obligatory.
The seal has additional dust sealing and (apparebtly according to the blurb) " the seal lip runs in the correct place on the seal journal of the crankshaft".

To be honest I don't know what that means.
Why would the OEM seal not run in the correct place ?
Maybe it means that they think that some non-OEM ones don't run in the correct place. ;)
 
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