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It's petrol......sorry...should have mentioned that
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Don’t think I’d be too worried about it . Check it again with a cold engine after an overnight stand , on level ground . It’s very easy to overfill modern engines , as it takes a long while for any residue to drain down to the sump , so if you top it up , you end up with an excess level .
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I have vague memories of a similar post from years ago. I recall one back roomer commenting that there is a danger of the big end bearings hitting the oil and thrashing it into a foam.
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there is a danger of the big end bearings hitting the oil and thrashing it into a foam.
They used to call it 'splash lubrication' before the days of oil pumps.
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I thought the danger of over-filling engine oil was that it stresses oil seals and may lead to leaks.
Edited by FP on 11/02/2022 at 20:13
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I thought the danger of over-filling engine oil was that it stresses oil seals and may lead to leaks.
I used to compete an Austin Maxi and experiencing 'oil surge' on corners, I consulted their competition department (those were the days, when you could ring someone up who had knowledge). They replied that I could overfill the sump or fit baffle plates, as they'd had no problems in the Mexico rally cars. I decided to try the overfill solution and prpomptly blew the clutch oil seal!
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I thought the danger of over-filling engine oil was that it stresses oil seals and may lead to leaks.
I used to compete an Austin Maxi and experiencing 'oil surge' on corners, I consulted their competition department (those were the days, when you could ring someone up who had knowledge). They replied that I could overfill the sump or fit baffle plates, as they'd had no problems in the Mexico rally cars. I decided to try the overfill solution and prpomptly blew the clutch oil seal
So perhaps that should be "Those were the days, when you could ring someone up who maybe had knowledge but would STILL give you bad advice ?"
Having said that, I can't offhand see why an overfilled sump is going to blow seals. Surely oil pressure is independent of oil level until the pump sucks air?
OTOH, big ends clouting/beating the oil surface and whipping it up seems to make sense.
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Is it a diesel, by any chance? Could it be oil diluted with diesel as a result of failed DPF regens?
Fuel dilution isn't restricted to diesels. IIRC petrol Honda CR-V's do/did it, to the extent there was a class action in the US
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Is it a diesel, by any chance? Could it be oil diluted with diesel as a result of failed DPF regens?
Fuel dilution isn't restricted to diesels. IIRC petrol Honda CR-V's do/did it, to the extent there was a class action in the US
All petrol engines have oil dilution to some extent, but the petrol evaporates away every time the engine warms up - the difference for diesels is that the fuel does evaporate at normal working temperatures.
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VW petrol engines oil level should be checked with the engine at normal working temperature. Level ground. Turn engine off. Wait 3 to 5 minutes. Then pull dipstick, wipe, redip and read. The oil level should not exceed the top of the marked area on the dipstick, refer to the manual for an accurate description as different styles of stick exist
Not above area B in these diagrams
www.golfmk7.com/forums/index.php?attachments/2015-.../
Overfilling can lead to catalytic converter and GPF damage, in cases where there is gross overfilling, the crank can thrash the oil and aerate it, which in turn can cause dramatic loss of oil pressure as the oil pump cannot pump aerated fluid. Also the possibility of excessive crankcase pressure causing oil seals to leak
Your son's car will have a level sensor, which is mainly there to monitor oil temperature and check for low oil level. Some cars do check for high oil level, but not sure in this case.
How far over the max marking is it? A few mm is not serious, 10mm or more would be worrying.
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Most manufacturers advise that overfilling can lead to catalytic converter failure, a very expensive mistake hence the max mark on the dipstick
With the electronic level sensor on a BMW the difference between low and Max is 1 litre so when the warning comes on you can safely add this amount
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Most manufacturers advise that overfilling can lead to catalytic converter failure, a very expensive mistake hence the max mark on the dipstick
Yes but it still comes down to the amount its overfilled by, a few mm most get away with, but more than that (depending on engine) can be more damaging, to a certain extent the downward force of the pistons compressing the air in the lower cylinder with overfilled oil the speed of compression is like air hitting concrete the force pushes the oil past the seals as it has nowhere to go, so its not just crank turning that causes a problem its the piston compressing the air in the sump as well
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Most manufacturers advise that overfilling can lead to catalytic converter failure, a very expensive mistake hence the max mark on the dipstick
Yes but it still comes down to the amount its overfilled by, a few mm most get away with, but more than that (depending on engine) can be more damaging, to a certain extent the downward force of the pistons compressing the air in the lower cylinder with overfilled oil the speed of compression is like air hitting concrete the force pushes the oil past the seals as it has nowhere to go, so its not just crank turning that causes a problem its the piston compressing the air in the sump as well
On a multi-cylinder engine wouldnt piston effects cancel out, what goes up must come down stylee?
Seems like clogging of crankcase breather circuit with excess oil spray might cause pressurisation, and excess oil blowby from the same source (which is burned) might also be expected to upset the catalyst
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the downward force of the pistons compressing the air in the lower cylinder
Wouldn't that only affect twin cylinder boxer engines and single cylinder engines. I've seen a twin cylinder boxer in an early Jowett that had a PCV (pressure control valve) in the oil filler neck that closed during the upward piston throw, thus creating a partial vacuum in the sump and opened on the downward stroke, thus allowing pressure to escape. This valve failed, causing oil to be blown out the engine everywhere.
Two strokes depend on crankcase pressure to transfer the fuel/air mixture into the combustion chamber.
I've seen a single cylinder four stroke golf cart motor (Yamaha IIRC) that uses the crankcase pressure pulses to operate the fuel pump.
Edited by bathtub tom on 13/02/2022 at 12:17
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Is it a diesel, by any chance? Could it be oil diluted with diesel as a result of failed DPF regens?
Fuel dilution isn't restricted to diesels. IIRC petrol Honda CR-V's do/did it, to the extent there was a class action in the US
All petrol engines have oil dilution to some extent, but the petrol evaporates away every time the engine warms up - the difference for diesels is that the fuel does evaporate at normal working temperatures.
My recollection is that the CR-V (and Civic) models affected had rising oil levels even in mild climates and reasonably long runs, though short tripping in the cold was of course worse. Since petrol is a mixture, the light end tends to evaporate and the heavy end tends to stick around, becoming concentrated over time and tending to degrade the oil.
IIRC Honda gave it the "They all do that sir" jive but fiddled around with the software, suggesting they all don't do it quite as badly. I think they settled in the end.
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The main reason for oil dilution in a petrol car is from cold starts, when the fuel/air mixture is deliberately rich to deliver unburnt fuel to the catalytic converter in order to heat it up, and very short runs so oil temperature is always too low to evaporate the petrol dilution consequently. A rare scenario for most people. Should never be a problem in a Golf with a close coupled Cat.
People should get into the routine of checking oil level regularly anyway, always after a oil change service. Use a constant method, taking care to make sure the accuracy of readings. Engine at normal working temperature, level ground, turn off, wait 5 mins and then check.
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The main reason for oil dilution in a petrol car is from cold starts, when the fuel/air mixture is deliberately rich to deliver unburnt fuel to the catalytic converter in order to heat it up, and very short runs so oil temperature is always too low to evaporate the petrol dilution consequently. A rare scenario for most people. Should never be a problem in a Golf with a close coupled Cat.
People should get into the routine of checking oil level regularly anyway, always after a oil change service. Use a constant method, taking care to make sure the accuracy of readings. Engine at normal working temperature, level ground, turn off, wait 5 mins and then check.
It's actually a common scenario when vehicles are used for predominantly short journeys - although not an issue when regularly interspersed with longer journeys.
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The main reason for oil dilution in a petrol car is from cold starts, when the fuel/air mixture is deliberately rich to deliver unburnt fuel to the catalytic converter in order to heat it up, and very short runs so oil temperature is always too low to evaporate the petrol dilution consequently. A rare scenario for most people. Should never be a problem in a Golf with a close coupled Cat.
People should get into the routine of checking oil level regularly anyway, always after a oil change service. Use a constant method, taking care to make sure the accuracy of readings. Engine at normal working temperature, level ground, turn off, wait 5 mins and then check.
It's actually a common scenario when vehicles are used for predominantly short journeys - although not an issue when regularly interspersed with longer journeys.
I avoid it by using butane as a choke substitute, though I suppose this would be difficult on a modern car unless one could somehow override the starting enrichment function, which I assume does not refer to mixture strength feedback from the O2 sensors.
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DP, SORRY
Edited by edlithgow on 14/02/2022 at 10:14
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