Thread: D4 massive oil leaks

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.

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.

Originally Posted by 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.

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

Originally Posted by Steve Alexion

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.

Originally Posted by Steve Alexion

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

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.

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...

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