D4 massive oil leaks

[Steve Alexion]

I'm hoping someone might have had my problem before. I have recently had the 6 speed transmission rebuilt by a ZF approved warranty repairer and fitted back into the D4 by my regular Landy workshop in NQ. Seems to be a great job as the gear shifts are smooth etc, so I was a happy boy at first. Being an enthusiastic driver, I did give it a bit of a load test and all worked well. However, before long I had spat out the front crankshaft oil seal and found out that this was a weak spot on the first of the 3 litre engines as they were just pushed into place with no retaining method. I paid for a new replacement cover with the updated oil seal and happily hit the road again, having written the whole ordeal off as a bit of bad luck.
Before long I noticed oily smells from the car and then noticed smoke coming from the bonnet area. I found that the tappet cover gaskets were both leaking and yet when the motor idles or is run at mid revs under no load it does not seem to leak. When the brakes are applied and the revs bought up (under load) the turbos obviously start to wake up and apply some pressure. This is when the tappet covers can be seen to bloat up and spray oil out the sides. It seems as if the turbo pressure is escaping into the cam areas when pressure is applied, but it is happening to both banks at once.????? I'm beginning to think this is more than coincidence.
I have been told that the 3lt. uses an oil separation system more so than a PCV valve and there seems to be no restriction there. I assumed pressure in the top end would bleed into the bottom end, however, this has not been the case. With the oil cap off and a light plastic bag clamped over the top of the filler hole, I can see the positive crankcase ventilation working as the bag slowly sucks in, yet the oil still pours out at the top.
I am reluctant to rip this apart again until I have a bit more knowledge up my sleeve and I assume I can't be the first one in the world to strike this problem.
Any suggestions?
Long winded story, I know, but thanks for reading so far and double thanks if you have the right answer.
Steve Lex
2010 Disco 4
TDI Disco 1. (bulletproof old favourite)

[Graeme]

The inlet manifolds, which cover the whole top of a head, on early engines are prone to cracking, with the right one (driver's side) the most common one to split first. Some people, including some workshop operators, advocate only replacing the leaking one as there's not much time saved by doing both together. My son's 2010 split the driver's side a couple of years ago but the passenger side is still original. The replacement manifold has obvious strength improvements.

There are lots of posts on the forum about the split manifolds of earlier engines.

[DiscoJeffster]

As Graeme says you’ve split a manifold and your oily intake airflow is escaping. Take it somewhere for a smoke test to confirm or someone who knows how to identify it.

[Steve Alexion]

As Graeme says you’ve split a manifold and your oily intake airflow is escaping. Take it somewhere for a smoke test to confirm or someone who knows how to identify it.

Thanks Graeme, Jeffster.
Split manifolds seems to be the popular consensus and I certainly agree that it fits the description, but why both at once? And does this have anything at all to do with the recently departed crankshaft oil seal? It seems awfully coincidental, to the point where I am questioning whether I have some sort of split second coordination issue between the new auto and the EMS that might possibly be causing a pressure spike. Am I reading too much into this?
A smoke test? What exactly goes on there?
Steve Lex

[kelvo]

A smoke test? What exactly goes on there?
Steve Lex
The intake gets pressurised with air with a ‘smoke’ trace added so that any leaks can be visually seen.

[josh.huber]

Thanks Graeme, Jeffster.
Split manifolds seems to be the popular consensus and I certainly agree that it fits the description, but why both at once? And does this have anything at all to do with the recently departed crankshaft oil seal? It seems awfully coincidental, to the point where I am questioning whether I have some sort of split second coordination issue between the new auto and the EMS that might possibly be causing a pressure spike. Am I reading too much into this?
A smoke test? What exactly goes on there?
Steve Lex

Don't over think it,

crank seal can be age or crank case pressure.. Shouldn't really be be crack case pressure. These engines breathe into a oil separator system. Which is basically the same as a Dyson vacuum before they vent into the turbo inlet.

The inlet manifold crack is due to age, you got lucky to last this long, and the air intake system. Are you sure it they both cracked? The crack from one does blow a lot of air too both sides? Mine was a huge mess

[DiscoJeffster]

I also had what I thought was a related leak that presented as “smoke” in the engine bay that was in fact an injector return pipe leak that was spraying diesel in the bay. In retrospect I was lucky the car didn’t go up in flames. This was repaired with a number of other leaks I had. Now my baby is leak free and clean as a whistle.

Oh final tip. The intake elbow that bolts to the throttle body is prone to warping and leaking down the front of the engine. This leads to a massive oil leak. Also the throttle body can split at the Y section also leaking oil and air for that matter.

I’ve had all these issues.

[Eric SDV6SE]

Just a note, but the leaking front crank seal is also a sign that the crank end float or thrust washers are worn/wearing, so the crankshaft MAY have too much end play. This can cause a multitude of issues if left unchecked...

[Steve Alexion]

Thanks to all so far, the smoke test is probably already done with the oil spraying out under pressure, so I definitely have at least one cracked manifold. Is there an oil gallery of some sort that would share the pressure from one tappet cover to the other, because if not I cannot see how the pressure would be in both housings without both being cracked internally.
Still suspicious.
Steve Lex

[Eric SDV6SE]

Thanks to all so far, the smoke test is probably already done with the oil spraying out under pressure, so I definitely have at least one cracked manifold. Is there an oil gallery of some sort that would share the pressure from one tappet cover to the other, because if not I cannot see how the pressure would be in both housings without both being cracked internally.
Still suspicious.
Steve Lex
Steve, these are intake manifolds with integral valve train covers. The air flow and pressure comes from the single intake and the flow is split at the Y piece sitting between them. Both see the same air flow and pressure.

[DazzaTD5]

If its a cracked inlet manifold, you wont need a smoke test to visually see it [tonguewink][tonguewink]

[Steve Alexion]

Agreed Eric. My question is however, if only one tappet cover has a crack in it, effectively allowing pressure into the tappet & cam area on say the drivers side, is there an oil gallery or similar that would allow the pressure to flow to the passenger side tappets. If not, I assume that I will find two cracked covers as both swell up under turbo pressure.
Steve Lex

[DiscoJeffster]

Agreed Eric. My question is however, if only one tappet cover has a crack in it, effectively allowing pressure into the tappet & cam area on say the drivers side, is there an oil gallery or similar that would allow the pressure to flow to the passenger side tappets. If not, I assume that I will find two cracked covers as both swell up under turbo pressure.
Steve Lex

The crack externally not internally to the engine. They expand and contract and eventually split to atmosphere

[Graeme]

The whole top of the cover is the inlet manifold which is why it expands under turbo pressure. The underside of the cover covers the camshafts except where the inlet feeds into the head.

Not quite the whole top but the escaping oily substance is inlet air and oil vapour, not oil directly from the sump.