My 6G74 has just developed a massive oil leak. Oil doesn't leak when idling, only under acceleration (lost approximately 3 litres after 30km trip). I cannot see any oil leaking from above but will purchase a couple of ramps to get underneath to inspect.

Any suggestions as to where this leak could possibly be coming from before I get underneath?

Rear rocker cover gasket is normally neglected and can be coming from there after a long time.

Was there an oil burning smell?

Have a look at the exhaust system below the rear bank.
If it is oil soaked, the problem is probably the rear rocker cover gasket.

The 6G engines are tilted back in the engine bay, to give clearance for the intake system. This puts more oil at the rear rocker cover/head joint than at the front.
When the rocker cover gaskets go hard, the biggest leak is at the back, unfortunately, and it dribbles onto the exhaust.
No ramps needed to check, just run your finger along the joint between the head and rocker cover on the rear bank on a cold engine, it it comes up all oily, you have found the problem.

If that is the problem, do the rocker cover gaskets and spark plug tube seals on both banks.
From my experience, the leaks start anywhere from 100,000 to 130,000 km. Your car may well be due for its third set after 270,000 km. Good idea to degrease the back of the engine and exhaust system once the new gaskets are in.

Really Max, 3L in 30km from a rocker cover gasket? Does that not make sense to anyone else?

If it were leaking at that rate there'd be huge plumes of smoke from the exhaust. I would expect these leaks to develop slowly and slowly get worse... Not suddenly start dumping litres of oil out.

I'd be looking at something more simple. Oil filter leak/damage, or sump damage.

You can't be losing 3L of oil in 30km without a major, major mess under the bonnet - unless it's dropping straight onto the ground.

Really Max, these are tilted and then the Oil runs from the front head, all the way through to the back head, through thin air........

OP, you need to have a good look around, what it sounds like to me is a blocked breather, transfer pipe and PCV causing pressure to build up in the bottom end and top end under load, the oil will then push past the seals due to pressure build up.


Also 3l in 30km, I would expect to see oil under the car all the way to the rear bar, we had a wagon in recently which even had oil blown up onto the rear window

Really Max, these are tilted and then the Oil runs from the front head, all the way through to the back head, through thin air........

Also 3l in 30km, I would expect to see oil under the car all the way to the rear bar, we had a wagon in recently which even had oil blown up onto the rear window

No Mal, in normal running the oil level in the rear head is higher up on the joint between head and cover because of the way the engine is tilted backwards. No black magic involved.
How do I know this? Simple, pulled both covers off a hot engine. Not much oil out the front when the cover came off, lots from the back one, straight onto the exhaust of course.

You are right though, the quantity lost would indicate a really heavy leak. There should be an oil trail on the roadway for that 30 km! lol

One of my brothers has lost 2-3l over the space of 40km drive through the hills.

The first indicator of a problem was the strong oil burning smell though.

Thanks for the extremely prompt replies fellas! Some of your suggestions I have just looked at prior to reading your responses.

I replaced the oil filter initially ( as soon as I realised the oil was bleeding) as I though that this could be part of the issue.

I purchased some ramps after my initial post this morning and have just put the car up on ramps and checked the sump and there is no damage. Just as stated by flyboy.

I have sprayed a generous amount of degreaser to clean the area from under the vehicle. There is no evidence of oil from the front rocket cover. The four litres I put in the other day is still holding - just checked.

I have a scoria driveway (sucks everything into it) and didn't notice any oil until looked at the sealed road. Just as Madmagna stated, there is plenty of oil under the car and on my rear window. I have left a trail along a 1km stretch of road but then the sped limit hits 100km. I didn't see it until I removed my trailer. I was using the jockey wheel as I was removing the trailer and it was covered in oil. The trailer did not have a heavy load in it.

As for the burning oil smell, it is minimal. I had worse by accidentally spilling oil when topping it up!

I will check breather, transfer pipe and PCV as suggested by Madmagna.

Madmagna, I have a wagon so what was wrong with the wagon you have just repaired?

Max, I will be blunt here, YOU ARE FULL OF SHIT...there, now I feel better

IF you have an engine with an issue of oil draining back to the sump, then that is YOUR issue, not everyone's. Now go away and stop confusing people.

OP, the wagon had a torque converter seal failure so different to what your issue is all together.

Most seals and gaskets will simply leak when at idle if they are damaged, if is a pressure issue then at idle you will not generally have an issue unless your motor is like Max's motor and for some reason rotated 90 degrees to the rear.....