Just Back From doing the NCT

Altreab

Hi All
Just back from the NCT and thankfully it passed However the tester did mention that i was borderline on the level of engine oil. The oil level was a bit too high on the dipstick (fair cop he was right). He let it though and did the full NCT.
He did comment that in Ireland that 90% of mechanics overfill engine oil especially in diesel engines. Has anyone else found this to be the case?

P.S I would have been SOOOOOO peeded off to fail the test because the oil level was slightly too high.!!

maly07@poczta.o

oh yeah, everytime i get the oil changed i have a look at the dipstick later on, and its way over the recommended level!

I havent got much clue about cars, just hope it wont do any damage to the engine...

crosstownk

I can't understand why mechanics overfill.

Firstly it costs the customer more, secondly there are no benefits in having more oil and thirdly, excessive oil can damage the catalytic convertor.

Just fill it to the max and no more.

mloc123

Did the guy at the nct leave the car to sit for long enough with the engine off to let the oil drain back into the sump? Sounds like he didn't know what he was on about, I presume he dipped it straight after he turned the engine off when the oil was still up in the head etc.? Dip it in the morning before starting the engine on level ground to get an accurate reading.

JHMEG

crosstownk wrote:

I can't understand why mechanics overfill.

Because they don't wait for it to settle so they estimate how much a "fill" will be.

I have heard the theory about cat damage but I don't understand how it could happen.

Oil ending up gunking the throttle body (causing the plate to dangerously stick) through over filling is a much more serious problem, particularly in VWs.

Altreab

mloc123 wrote:

Did the guy at the nct leave the car to sit for long enough with the engine off to let the oil drain back into the sump? Sounds like he didn't know what he was on about, I presume he dipped it straight after he turned the engine off when the oil was still up in the head etc.? Dip it in the morning before starting the engine on level ground to get an accurate reading.

Yes he did wait actually. He was actually spot on regarding the oil level.

Altreab

crosstownk wrote:

I can't understand why mechanics overfill.

Firstly it costs the customer more, secondly there are no benefits in having more oil and thirdly, excessive oil can damage the catalytic convertor.

Just fill it to the max and no more.

Im guessing that many mechanics are still thinking of then as "oil burners" therefore its alright to "overfill" as "sure she will burn the extra oil anyway". They seem to have forgotten that modern engines tend to burn bugger all oil between changes.

Wossack

if the oil level becomes high enough in the sump, high enough to reach the crank, it can be whisked into a foam by it. This aerated oil is more compressible so you lose oil pressure - loss of oil pressure can be pretty catastrophic to your top end and your bearings

more common though, is due to there being less space in the engine, the overall interal pressures are increased which can blow seals + gaskets.

so I hear anyway, none of this is first hand, but are rather the reasons why I check the oil level after services