Thread: How much oil should a 300tdi use?

Originally Posted by weeds

interesting that there is an increase in oil usage after the mod

Yes, the oil consumption started at the time the gas was first used. It was detonating part of the time, mostly on about two-thirds throttle. I only drove it a short distance before I realised, maybe 40 kilometres.

I can't think of how the D-gas could have caused the problem though. If it had broken a ring or blown a head gasket, I would expect things to be much worse. It still runs perfectly in every other respect.

Any ideas gratefully received!

Best for the New Year, everyone,

Cheers,

Paul

Originally Posted by 87County

have you checked all the usual suspect spots for oil leaks, rocker cover, crancase vent, vacuum pump, front & rear mains seals etc ?????

oh, and is the oil filter seal ok ??

Yes, there are no oil leaks whatever, dry as a bone underneath. I would make a snide comment here, but I also have two TD5 'Fenders which are also dry underneath. British seal technology has come of age!

Cheers,

Paul

All engines use some oil, by design. Some manufacturers of industrial diesel engines specify oil consumption as a percentage of fuel burned.
In the case of a diesel, soot can replace most of what is burnt in normal combustion, causing people to think their engine 'uses no oil'.
Petrol engines also dilute the oil, leading to the same misconception.

5 liters in 11,000km is tending to the higher side of things but is not really a big deal. I wouldnt be spending any money to correct it unless something was obviously wrong (and it doesnt sound like it)

Originally Posted by mark2

All engines use some oil, by design. Some manufacturers of industrial diesel engines specify oil consumption as a percentage of fuel burned.
In the case of a diesel, soot can replace most of what is burnt in normal combustion, causing people to think their engine 'uses no oil'.
Petrol engines also dilute the oil, leading to the same misconception.

5 liters in 11,000km is tending to the higher side of things but is not really a big deal. I wouldnt be spending any money to correct it unless something was obviously wrong (and it doesnt sound like it)

Most manufacturers have an 'acceptable' oil consumption rate, often around 1/2 litre or so /1000km. Some engine's such as Honda's seem to use a fair bit oil. Combination of low tension oil rings, design, etc.
Yes, all engines consume oil, a % will go past rings and seals but 5litre/10,000km is too high in my experience, although I have used near 2l/8000km when a valve stem seal was torn.

Soot at that mileage will be 0.2% or less if the engine is in a good state of tune, so you won't see the difference on the dispstick. At 10,000km I was averaging between 0.6 and 0.8% soot, again unable to see on the dipstick compared to oil consumption.

Fuel dilution issues are as big or bigger in diesels than petrol engines and a lot of people would be horrified to see what was really happening in their engines if the oil was tested yearly to set a trend. Unfortunately most (all ?) Australian labs can only test to >1%, which isn't accurate enough IMO, so you don't really get to see if you have an injector or fuel issue as accuracies below 0.5% are really needed to be tested.

I'd still be looking at valve stem seals and turbo seals and possibly a leak down or compression test, but I get OCDish when it comes to potential problems.
One good thing with oil consumption and adding fresh oil is that you are replenishing the oils additive package as it is consumed with normal usage.

1/2L in 12 months (about 5,000km) and I'm about to do an oil change, if I get a break in the weather

You need to remember the turbo will use oil,there is no way to make them not consume it. Pat