Thread: Crankcase ventilation.

Originally Posted by Trunksie

RAM 1500 (ZF 8HP70 / 8HP75)
BMW X5 30d / 40i (ZF 8HP)
BMW X6 30d / 40i (ZF 8HP)
Jeep Grand Cherokee (ZF 8HP70 / 8HP75)
Audi Q7 3.0 TDI (ZF 8HP)
Audi Q8 3.0 TDI (ZF 8HP)

These all use the same trans as the disco and all have issues with overheating when towing.

The ram is renowned for overheating the trans and causing failure.

The fix is always an aux trans cooler

But does the D5 have an overheating problem?
I'm not saying it doesn't, but just because the 8HPXX overheats in a Ram doesn't mean it will in Land Rover.
Have you plugged in an OBD II reader and looked at the gearbox temps?
And don't forget to get it serviced at a reasonable interval, not what the book says, particularly if towing.

Tony

Originally Posted by Graeme

Shack, you are indeed having one of those days as the vehicle has a D350 engine which has a turbo, into which the crankcase vents.

The OP was making it sound like it fed directly into the inlet manifold. I still don't think this correct, I'm guessing it feeds in BEFORE the turbo, all turbo diesels I've worked on do that. So a Provent or similar would suffice.

If indeed it does feed into the inlet manifold inside the head somehow I'd be interested to know how that works, especially in a turbo diesel where inlet manifold pressure would usually be higher than crankcase pressure.

Am I correct or has tech gone past me?

It's quite possible it has!!

It's quite likely I've misread the whole thing anyway.

Originally Posted by Trunksie

RAM 1500 (ZF 8HP70 / 8HP75)
BMW X5 30d / 40i (ZF 8HP)
BMW X6 30d / 40i (ZF 8HP)
Jeep Grand Cherokee (ZF 8HP70 / 8HP75)
Audi Q7 3.0 TDI (ZF 8HP)
Audi Q8 3.0 TDI (ZF 8HP)

These all use the same trans as the disco and all have issues with overheating when towing.

The ram is renowned for overheating the trans and causing failure.

The fix is always an aux trans cooler

If the auto is locked up a larger trans cooler may help,although i have never heard of a ZF 8HP overheating in a LR.
If the auto is not locking up at times, due to the way it is set up and programmed by the manufacturer,in those vehicles,a larger trans cooler may not help.
Tuning the auto is then the answer,which is easily done and common in some of the Jap 4X4 vehicles,so the auto is locked up more often.

The crankcase certainly doesn't vent directly to the inlet manifold, with the usual method having it T'd into the primary turbo inlet stream eventually ending-up in the inlet manifold to combine with exhaust particles to form gunk. I obvously don't know if the OP thought that it does vent directly into the inlet manifold or he just took a short-cut in describing the path.

My preference is to stop EGR in normal operation rather than install a Provent although with the exhaust gas reportedly sourced from after the DPF, perhaps there's minimal carbon particles to mix with crankcase oil and therefore intake gunk might not be such an issue with the Ingenium engines.

Edit: I'd like to know where the EGR filter is located and how accessible it is for cleaning or replacement.

Edit 2: The EGR filter reference might only be for the 4-cylinder 2.0L.

Combustion happens in the cylinder and cylinder pressure spikes.
A small amount of gas leaks past the piston rings (even on a healthy engine). That leakage is blow-by.
Blow-by enters the crankcase (the space around the crankshaft inside the engine).
That gas pressurises the crankcase and picks up oil vapour / oil mist as it swirls around.
The engine’s PCV / crankcase ventilation system gives that pressure a controlled way out:
Through a breather/PCV outlet on the rocker cover/valve cover or crankcase.
The flow usually goes through some form of oil separator / baffle / cyclone separator (built-in to the cover or a separate unit) to drop out larger oil droplets.
The remaining vapour/gas travels through a PCV hose toward the intake system.
Intake vacuum / turbo inlet suction pulls it along:
Naturally aspirated: manifold vacuum draws it in.
Turbo/diesel: suction at the turbo inlet (pre-compressor) and/or a regulated PCV path moves it.
The vapour re-enters the inlet tract (commonly into the intake manifold on petrol, or into the turbo inlet/intake piping on many diesels).
Once back in the inlet, it gets mixed with fresh intake air and goes through the engine again—sometimes leaving oil film in pipes/intercooler/manifold (especially if there’s lots of blow-by or weak separation).

AI rears its head again...

I'm wondering who is hiding under the bridge. "Trip, trap, trip, trap! "