Oil Leak - Timing Cover

Greetings,

Defender 110, 300tdi.

Had a persistent oil leak towards the front of the engine for a while now and I was confident it was the front crank oil seal.
So after purchasing a timing belt kit, front crank oils seals (1 behind crank pulley, 1 in timing case cover), cam shaft oil seal and a variety of other items I got to work today and removed the Timing front cover to see what is in the attached image.....



A perfectly clean timing case except for some slight rubber fuzz. I was expecting to see oil coming from at the rear of at least one pulley. In my second image however there is oil present in a lower bolt hole for the timing case cover.



I suspect this is the source of my leak. The bolt when removed was covered in oil.
Where could this oil could be coming from? Any ideas?

theres oil between housing and block front, id think the gasket that seals between the two is broken at that stud hole allowing oil to run along the bolt, either you strip back and fit a new gasket or try silicone sealant

Thanks for the reply. Removing the timing housing now is a little more work than I planned for at this time to replace that gasket. So do you mean use silicone in that bolt hole and around the head of the bolt?
If that is what you mean, I am a little concerned that the oil will build up and make it's way out elsewhere.

LeftFoot said:

Thanks for the reply. Removing the timing housing now is a little more work than I planned for at this time to replace that gasket. So do you mean use silicone in that bolt hole and around the head of the bolt?
If that is what you mean, I am a little concerned that the oil will build up and make it's way out elsewhere.

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yes you could clean hole out with a can of brake clean insert bolt partially and fill gaps around the bolt with silicone sealant,if you apply before fitting bolt you run the risk of forcing sealant in to the threads and hydraulicing the block

Just a follow-up...
The timing belt, idler and tensioner and timing case front gasket replaced. Silicone was used in the suspected bolt hole and after reassembly the entire area was degreased and washed.
I made a couple short journeys between yesterday evening and this morning and so far so good, no leaks.
So I guess I should sit and wait now for it to start p*ssing oil from somewhere else.....

Thanks @ James Martin.

LeftFoot said:

So I guess I should sit and wait now for it to start p*ssing oil from somewhere else.....

Thanks @ James Martin.

Click to expand...

Don't worry, the oil behind that casing is meant to be there so it's not being naughty and looking for another way out. You've just developed a leak between the oil side, through the narrow bit of gasket, to the stud hole. Whoever put the gasket on might have caught that thin bit of gasket and split it. If you de-greased the stud hole enough for the silicone to get a good hold, then you've probably stopped the oil seeping through the gasket breach.

Could it not be that the leak was caused by someone getting the timing cover bolts mixed up and winding in one that was too long forcing it through the end of the bolt hole or causing a crack there allowing the oil to find it's way out ?

LifetimeLandy said:

Could it not be that the leak was caused by someone getting the timing cover bolts mixed up and winding in one that was too long forcing it through the end of the bolt hole or causing a crack there allowing the oil to find it's way out ?

Click to expand...

A conspirasy theory, I like it.