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Discussion Starter · #1 ·
Yesterday, I changed the engine oil on my wife's 2004 X3 3.0i. I used an oil extractor to suck the oil through the dipstick tube. To my surprise, I got almost 9L of old oil. I was able to pour in around 6.5L of the new oil. The old oil looked dark. I didn't see any evidence of coolant in it. Is it possible that something else could get into the engine oil?

The service record shows that the dealer exchanged around 6.5L of the engine oil last time. So, I guess the previous owner somehow overfilled the engine oil. My wife probably had driven the car with too much engine oil for a few thousands miles before my oil change yesterday. Should I be concerned?
 

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MT = Doppler Shifting
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Well, the problem with excess oil is that you effectively confined too much of an incompressible fluid in a given volume, and that increases the pressure. This puts extra stress on things like seals and gaskets. And an extra 2.5 liters of oil is a 38% increase in fluid level; I question whether the crankcase could accommodate this much of an excess, especially without the vehicle giving an over-pressure warning...

Does anyone know whether there's still residual (undrainable) oil left in the crankcase if you use the drainplug as opposed to the siphoning method described by the OP...? If so, the dark oil you were pulling out may have been laced with sludge from the bottom of the crankcase.

That question aside, I would check other fluid levels (e.g., coolant) to ensure none of them have reduced levels, inspect for oil leaks around seals/gaskets for other evidence of an over-pressure event, then monitor the fluid levels closely for a while.
 

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I don't think you have anything to worry about regarding the color of the oil. My oil always gets dark quickly after an oil change. I've heard that synthetic oil gets darker quicker than conventional oil (not sure if it is true)
 

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An oil extractor can get more oil out that is below the level of the drain plug, by some accounts.

But the tip of the tube has to be moved around in the right places to accomplish that.

And I doubt it would be more than 1L.

After 2006, I understand the drain plug is a bit lower in the pan, and the hole points more downward than in your 2004.

So maybe it's possible that a couple of litres could be undrainable by conventional means in the M54 engine.
And the other 0.5L was a real overfill - dunno.

In the absence of signs of frothing of the original oil, just assume you have done a timely thing in putting in the right amount of fresh oil.
 

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Discussion Starter · #5 ·
Thanks for all the responses.

I guess it's really my fault. I did check the oil level again once after we bought the x3. I noticed that the oil was so high that it covered some part of the top fin-like thing. I think the level was over MAX by about half of the distance between MIN and MAX.

According to the manual, I should bring the engine to the normal operating temperature, shut down the engine, wait for five minutes, and check. Since I checked when the car had been parked overnight, I assumed that a lot of oil had returned to the oil pan and made the oil level extremely high. I was concerned about low oil level and didn't think of that something else could get into the oil or someone could mistakenly add too much.

I did get P0599 and the low coolant light a few months ago. I bought the thermostat assembly w/ sensor and was planning to replace it. However, the CEL light soon disappeared and the coolant loss has been manageable. So, I have been putting off the job. As mentioned before, I didn't notice any coolant in the engine oil.

I replaced five of the six spark plugs last month and noticed some engine oil in the 3rd spark plug housing. I left the 3rd spark plug alone and decided to replace the valve cover gasket first. I have the new gasket. However, I'm not sure when I would do the job. The leaking valve cover gasket is probably from the age instead of extra pressure.

Where should I look for seal and gasket leaks? Right now, I'll definitely monitor the oil level for a while.
 

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Thanks for all the responses.

I guess it's really my fault. I did check the oil level again once after we bought the x3. I noticed that the oil was so high that it covered some part of the top fin-like thing. I think the level was over MAX by about half of the distance between MIN and MAX.

According to the manual, I should bring the engine to the normal operating temperature, shut down the engine, wait for five minutes, and check. Since I checked when the car had been parked overnight, I assumed that a lot of oil had returned to the oil pan and made the oil level extremely high. I was concerned about low oil level and didn't think of that something else could get into the oil or someone could mistakenly add too much.

I did get P0599 and the low coolant light a few months ago. I bought the thermostat assembly w/ sensor and was planning to replace it. However, the CEL light soon disappeared and the coolant loss has been manageable. So, I have been putting off the job. As mentioned before, I didn't notice any coolant in the engine oil.

I replaced five of the six spark plugs last month and noticed some engine oil in the 3rd spark plug housing. I left the 3rd spark plug alone and decided to replace the valve cover gasket first. I have the new gasket. However, I'm not sure when I would do the job. The leaking valve cover gasket is probably from the age instead of extra pressure.

Where should I look for seal and gasket leaks? Right now, I'll definitely monitor the oil level for a while.
the only reason why you need to warm up the engine is that oil expands when warmer so you get accurate reading, and waiting 5 minutes is required for oil to drain back down into the pan.
 

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... decided to replace the valve cover gasket first. I have the new gasket. However, I'm not sure when I would do the job. The leaking valve cover gasket is probably from the age instead of extra pressure.

Where should I look for seal and gasket leaks?
I'd check all around the engine block, anywhere there is a gasket between parts: valve cover, oil pan, etc. Checking from underneath the engine might be more revealing, as you might spot an oil drip more readily from below. If you do spot a drip or leak, keep a close eye on it and your oil level until the offending gasket can be replaced.

I don't want to sound alarmist, but in retrospect, I'd give the block, valve cover, and oil pan themselves a good "once-over" too; with that much excess oil in the engine, I'd personally want to be sure the pressure didn't build enough to crack metal...
 

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Discussion Starter · #8 ·
I'd check all around the engine block, anywhere there is a gasket between parts: valve cover, oil pan, etc. Checking from underneath the engine might be more revealing, as you might spot an oil drip more readily from below. If you do spot a drip or leak, keep a close eye on it and your oil level until the offending gasket can be replaced.

I don't want to sound alarmist, but in retrospect, I'd give the block, valve cover, and oil pan themselves a good "once-over" too; with that much excess oil in the engine, I'd personally want to be sure the pressure didn't build enough to crack metal...
Thanks for the feedback. I'm going to get under the car to check and continue to monitor the oil level.
 
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