Re: Engine Oil level drops too quickly
A very high level overview of typically how it works -
Engine oil with the engine off, sits in a tub call an oil sump. The sump sits at the bottom of the engine. When the engine is started, the oil pump would get the oil movin up into engine block to lubricate the pistons. The engine oil would be lined on the walls of the cylinders of the piston heads as a result.
There is a ring around the piston head. 2 of the main purpose of this ring is to regulate oil consumption and to reduce the amount of gases transferring to the crank. When this ring is affected by wear and tear - the engine oil lined on the cylinders would start to seep through the ring as vapor resulting buildup of gases and vapor would start to form which affects the piston's performance. The engine oil might also end up being burnt as it seeps through into the combustion area and ended as carbon formed on the Pistons and valves.
This is where the idea of a Positive Crankcase comes in - it is designed with 2 ideas - it has to be emissions friendly as these gases are quite toxic and the evacuation of these gases for sustainable performance. Thus the PCV would operate by vacuum and have these gases directed back to the intake manifold to be re-burnt. The oil separator would act as a condenser to allow the oil vapors to return back to the oil sump via a one way check valve.
As you can see the entire process happens in a closed environment. So the question is where did the oil go ? Some ideas -
- Leaks where the oil would flow through e.g Oil sump, valve cover, OFH, flywheel, turbo oil lines, coolers, plugs .......
- Evaporation
- Carbonization e.g oil turned to carbon around the pistons and cylinder heads and valves
- Sludge formation
Sometimes changing to a thicker engine oil might address evaporation. But the sure way to address all the issues is via an overhaul.
In this case the the TWS (not edge) 10w60 is thicker and thus slightly harder to seep through the piston rings or gaskets. But take note that the flash point is lower on paper than the 0w30. But the viscosity of the 10w60 being that it's is twice the 0w30 means that it is a drag to performance and just serves to cover up the real issues happening within the engine block (thicker fluid insulates noises better etc)
Preventive maintenance via regular oil changes and having the ride reach operating temperature often help keep the sludge away. If the ride has only a year or less to go then which ever cost effective method to keep the lights on would make sense. Conversely, if the ride has 5-6 years to go - ignoring the root cause of the problem is just going to potentially deprive one of the joy of driving a BMW.
ISAMS;1114065 said:
Hi codewerx,
thanks for the info. I do witness significant lower engine consumption for my previous 9.year.old e90 last time compared to using PML RECOMMENDED oil specs. I changed to castrol 10w-60 oil depletion rate improve dramatically. I was told and explained on flash point follow the instruction and saw the improvement.
i do know what is pcv and oil separator as a driver but not as a filed mechanic. Currently am driving 2009 late model e60. This pcv set Servicible by any repair kit? How often should we change by right would that improve lessen the oil evaporation matter some of us experience ? Last time they did not tell me its pcv . I did my.research and found out there is this part. However, 2 workhops did told me do top overhaul for the engine oil depletiin issue.
Please kindly enlighten us more knowledge. Thanks!
