Excessive oil consumption

In the great plan of things simply claiming excessive oil consumption is not enough. You think you know what you mean but how much is excessive?

Car manufacturers insist before taking any warranty action for excessive oil consumption a test must be carried out to decide whether the consumption is excessive and whether repair will be economic. Even though your car isn't under warranty the principle generally will be the same.

An oil consumption test is carried out after a few basic checks and means topping up the oil exactly and then driving 750 miles of mixed town and country driving that doesn't include any sustained high speeds or heavy congested traffic. The oil is then checked and topped up exactly and if the quantity is less than 1 litre it is considered acceptable due to any improvement being uneconomic to achieve.

How many miles is your car covering per litre?

Of course if the engine is producing smoke things are somewhat different...

White smoke is usually coolant burning, but you say no loss of coolant, so must be oil burning. PCV is possible fault, especially since you say smoke is intermittent. Part itself should be cheap, less than $20. One your car I believe it is located in a pipe running from intake to valve cover.

definitely an oil consumption problem. How many miles? Could be worn rings and or valve guides. The oil light on when hot indicates low level or possible or weak oil pump. Check compression for possible head gasket or cracked head. I wouldn't drive it untill diagnosed.

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oil consumption of say 1/2 litre in 5.000miles would be normal even 1 litre in 5.000miles would be ok but any thing else is staring to be excessive. Oil consumption is an indication of a problem with the oil control rings and valve stem seals . Add to that your statement of a knock coming from the exhaust I would be inclined to have a compression test done to determine the condition of the engine . I consider 65.000 miles to be a little young for bad oil consumption so with the noise I would suspect a broken ring and a scored bore

Wherever the engine stops there will be at least a couple of valves held open and overnight the force of the valve springs can force the oil from some of the hydraulic tappets (if fitted). Some engine designs can take as much as 20 miles to cease tapping...

Some timing chain tensioners are oil damped.

If noise disappears when you top up the engine oil the clear solution is to top up more often - the engine oil level should never be allowed to fall more than 1 litre below the maximum level and it should never be overfilled.

Locating and curing the cause of excess oil consumption can be expensive and complex and the process involves a certain amount of guessing and eliminating so sometimes it is better, quicker and cheaper just to have the engine overhauled.

The general rule is it isn't economic to repair excess oil consumption unless it exceeds 750 miles per litre of mixed driving that doesn't include any sustained high speeds unless there is smoke when the engine must have attention or be scrapped.

Before testing the oil consumption the engine breather should be checked and the oil topped up accurately.

If there are no visible crankcase emissions caused by excess piston ring/bore wear, the most likely cause of excess oil consumption is the valve stem oil seals - unless the engine is so gunged inside the oil being pumped to the top of the engine can't drain back fast enough...

All engines burn oil. Yours burns 1/2-qt every 3,000 miles. That's NOT excessive

There is a lot wrong with "low oil" and low oil is not normal in a low mileage healthy engine.

The dealer is fobbing you off in the hope you will go away.

If the oil is being changed at least every 5000 miles or so there should be minimum oil depletion between changes with only very minor top up needed. Some oil consumption is normal but it should be minimal.

If the oil level is dropping to a very low level in about 4000 - 5000 miles of normal motoring you have a significant problem. The oil is either leaking out or the engine is burning excessive oil or a combination. If there is no leak through faulty seals or by other means such as oil escaping into the cooling passages of the engine, then there is excessive burning.

These engines are known for excessive oil consumption because the problem is a common one in the 06, 05, 04 and previous year builds back to about 98/99. The dealers know all about this problem - as does BMW - and they will try to fob you off until the car is out of warranty because the fix is expensive.

From what you say the problem has not been fixed on your car. Document the oil loss and insist on your warranty rights because your engine is using excessive oil and this is NOT normal in a properly functioning motor with as few miles as yours has. Make it clear to the dealer that you are well aware that excessive oil consumption is a common problem in many of the 325 petrol engines and you want it fixed under warranty.

Then sell the car as these vehicles will cost you quite a bit in repairs once out of warranty and once you clock up around 60000 miles or more. If you have an auto you can expect major problems at about 65000 miles (later if you are lucky) and replacement of the transmission will be necessary. Once you notice any significant problem with the auto transmission it is on it's way out.

Cheers
Sean

hi, this consumption seems high, i would take it to a dealer and ask them to check the oil sensor.......
P.S. is there a lot of smoke coming from the exhaust, if so, it may be burning a little oil, ask dealer to check it

I have a 2004 pathy-same car.All paths push oil past the lifters-does not burn oil.I have to add about 1-1/2 quarts in between 3,000 mile oil changes.I check the oil when I gas up and add as needed.Hope this was helpful.

2006 C4S Tip, 26,000 miles Now in Porsche dealership having the engine stripped. They are suggesting that one of the pistons is starting to fail. Their diagnostic equipment shows no fault codes but further testing has shown that one bank is having to work harder than the other side. Their prognosis is a new engine. Do not let your warranty expire!!! Also see here: http://www.pistonheads.com/gassing/topic.asp?h=0&f=48&t=731645&mid=154532&i=0&nmt=OPC - Does this sound odd to you?&mid=154532