Engine oil overfill

[E55BOF]

Given the actual measured amounts, my money would be on somebody putting in litres but using the pints maximum figure. If it has done 1000 miles that way, it should be OK now; I'd not worry about it.

 

[grober]

My guess bearing in mind the volumes involved is they filled it twice. Or possibly failed to drain before "refilling" They then added 4 litres to the existing 5.5- quick check of level showed oil past the max- but that's OK cos they only put in 4 right!

 

[Bellow]

My guess bearing in mind the volumes involved is they filled it twice. Or possibly failed to drain before "refilling" They then added 4 litres to the existing 5.5- quick check of level showed oil past the max- but that's OK cos they only put in 4 right!

Distinct whiff of gun smoke?

 

[Major774]

Oil does expand when heated.

I use the drain method and still warm up the car before releasing the drain plug. My 10 litre drain pan does get very close to full and my engine takes 8.5 litres. I know it’s not overfilled because I service my own car.

As you are using the extraction method, you would had to warm up the car so that oil is not so dense and free flowing. You probably had approx. 1 litre less of the overage, but you’re right... monkeys overfilled it.

 

[Bellow]

Oil does expand when heated.

By 0.0007 per degC. So, 100C increase expands it by 0.07.
0.07 x 5.5l = 0.385l.

Volumetric or Cubical Expansion Coefficients of Liquids

 

[markjay]

Not necessarily true.
Depending on the ability (or otherwise) of the spaces beneath the pistons to communicate with each other, the localised pressure increase can damage rings - the multi-piece oil control ring being the most vulnerable. Hence the immediate need to monitor oil consumption.

I don't disagree, yes this can happen, but.... in most cases oil pushed above the oil scraper rings and the compression ring and makes its way into the combustion chamber actually prolongs engine life by lubricating the bores. In the olden days we used to say that an engine that consumes no oil at all is too tight will wear quickly.

 

[Bellow]

I don't disagree, yes this can happen, but.... a in most cases oil pushed above the oil scraper rings and the compression ring and makes its way into the combustion chamber actually prolongs engine life by lubricating the bores. In the olden days we used to say that an engine that consumes no oil at all is too tight will wear quickly.

If the oil has got past the scraper ring - the ring has failed. They don't self heal.
Oil in the chamber reduces octane rating and is detected by the Lambda sensor as fuel. Combined, the ECU retards timing and weakens the mixture to compensate. Then the exhaust valves fail. Been there, done the rebuild, and have the burnt valves to prove it.

 

[E55BOF]

By 0.0007 per degC. So, 100C increase expands it by 0.07.
0.07 x 5.5l = 0.385l.

Quite true, but depending on the actual shape of the space into which the oil expands as it warms up (is it full of crankshaft, big ends, oil pickup, etc etc?) that extra 1/3 of a litre could just possibly be significant. Almost certainly not, because I can't imagine a manufacturer leaving some leeway 'just in case', thouigh.

That said, if the car has done 1000 miles with no apparent ill effects, I'd not worry about it; there's nothing you can do about it now if it has, anyway...

 

[Bellow]

The oil can only be warmed while circulating so plenty space in the sump.
The overfill being discussed is 4 litres. More than ten times thermal expansion (and that assuming a 100C increase which is much more than the temp when drained).

 

[190]

I'm thinking maybe Mercedes stipulates 5.5 to have it within a safe zone between min and max and to give that extra safety buffer from over filling

My experience with the first oil change on an M271 was similar if nothing like so extreme. I vacuumed 6.5 L out and putting 5.5 L back only gets it part way between min and max.

Fuel dilution of the oil got mentioned as a possible factor. While it's natural to think highly volatile fuel would evaporate off completely, apparently it doesn't. I don't pretend to understand the chemistry but the oil experts find some significant percentage stays in the oil and can be detected by used oil analysis. Neither issue explains 9.5 L so it was still overfilled.

At least you have the right idea, if you want to be sure it's done right, do it yourself.

 

[markjay]

OP: Ignore us... just drive the car, it's fine!

 

[ash1212002]

Oil does expand when heated.

I use the drain method and still warm up the car before releasing the drain plug. My 10 litre drain pan does get very close to full and my engine takes 8.5 litres. I know it’s not overfilled because I service my own car.

As you are using the extraction method, you would had to warm up the car so that oil is not so dense and free flowing. You probably had approx. 1 litre less of the overage, but you’re right... monkeys overfilled it.

Ran the engine at idle for about 30 mins with tec4 engine flush, revved it a few times to it to time.

By the time i switched the engine off temp needle was at 90 put the pela tube in and extracted away!

 

[ash1212002]

My experience with the first oil change on an M271 was similar if nothing like so extreme. I vacuumed 6.5 L out and putting 5.5 L back only gets it part way between min and max.

Fuel dilution of the oil got mentioned as a possible factor. While it's natural to think highly volatile fuel would evaporate off completely, apparently it doesn't. I don't pretend to understand the chemistry but the oil experts find some significant percentage stays in the oil and can be detected by used oil analysis. Neither issue explains 9.5 L so it was still overfilled.

At least you have the right idea, if you want to be sure it's done right, do it yourself.

So was you car over filled by 1 litre too?

I suspect the independent garage may have put 5.5 in but scratched there head thinking why is it only showing between min and max and for good measure decided to add another 4 litres in

Does that mean its not necessarily at the max point on the dipstick? So in theory you could add more oil to get to the max point on the dipstick?

 

[markjay]

Ran the engine at idle for about 30 mins with tec4 engine flush, revved it a few times to it to time.

By the tine i switched the engine off temp needle was at 90 put the pela tube in and extracted away!

If you leave the engine for 10-15 minutes after pumping out the oil, and then use the pela pump again, you will catch some more oil that drained down into the sump. If you really feel OCD then you can remove the sump drain plug and eave the car to drain overnight, but that's unnecessary....

 

[ash1212002]

OP: Ignore us... just drive the car, it's fine!

Interesting read, thank you all for your views.

What's happened has happened cant turn back time.

Will monitor the oil consumption, hopefully it doesn't consume oil

I may in 6 months time do another oil and filter service, without an engine flush and then stick to once a year service

 

[ash1212002]

If you leave the engine for 10-15 minutes after pumping out the oil, and then use the pela pump again, you will catch some more oil that drained down into the sump. If you really feel OCD then you can remove the sump drain plug and eave the car to drain overnight, but that's unnecessary....

Didn't remove the sump drain plug, but once all the oil was out waited 20 mins and extracted again was pretty empty by that point

 

[Bellow]

If you leave the engine for 10-15 minutes after pumping out the oil, and then use the pela pump again, you will catch some more oil that drained down into the sump.

A teaspoons worth at most.
I've removed my sump several times after first draining with a Pela and that's all there's ever been.

 

[ash1212002]

A teaspoons worth at most.
I've removed my sump several times after first draining with a Pela and that's all there's ever been.

Good to know! Pointless getting messy and removing the sump

 

[Bellow]

Good to know! Pointless getting messy and removing the sump

I had to remove my sump. But MJ doesn't want me to tell you why I had to....

 

[ash1212002]

I had to remove my sump. But MJ doesn't want me to tell you why I had to....

You gotta tell us now! Haha