Modest oil overfill - anyone encountered a problem?

Modest oil overfill - anyone encountered a problem?

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Discussion

Krikkit

Original Poster:

26,527 posts

181 months

Tuesday 20th June 2017
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Just a ponderment really, nothing that relates to a problem, but has anyone seen any issues directly caused by a slight (<10%) overfill of oil?

I'm not talking a fill it until it comes out of the filler moment, but a slight over-fill when servicing etc? Was just glancing at a reader's ride thread where he drained the oil on a new to him car because it was a bit over-full, despite having driven it for a few hundred miles by that point.

PositronicRay

27,010 posts

183 months

Tuesday 20th June 2017
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It affects some cars more than others, I overfilled by 1/2 ltr on a 7ltr sump so pumped it out (on the advice of a marque specialist) to the correct level.

A diesel I'd definitely be wary.

BluePurpleRed

1,137 posts

226 months

Tuesday 20th June 2017
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I put 2L too much into an old Vectra estate. Woops.

Going to pick my mate up from Heathrow. Anything other than the lightest of accelerator prods or over 3000 rpm and it had a better white smoke screen than a Panzer tank! I was amazed I was not pulled. I was creeping up the slip road on the way back hoping he would not notice. Luckily the effects of a baby and jetlag means he did not!

Drained the oil later when I got back and replaced to no ill effect. Apart from the oil filter spinning off.

That car got about 20L in 3 days . hahahah

GreenV8S

30,193 posts

284 months

Tuesday 20th June 2017
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If you over fill it to the point that it starts covering seals, you might find it drips a bit/a lot. Whether that matters is up to you.

If you over fill it to the point that the crank starts hitting the oil you will get a substantial increase in oil temperatures and probably increased blow-by and oil consumption. If you're in that situation you definitely want to lower the oil level.

If you're looking at it in terms of the dip stick, I would hope it's safe for at least a quarter of an inch, and that represents quite a lot of oil. I routinely over fill the V8S by that much to reduce oil surge on heavy cornering. Half an inch might be pushing your luck.


Krikkit

Original Poster:

26,527 posts

181 months

Thursday 22nd June 2017
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Interesting, thanks guys. I've seen a few cars/vans which are obviously overfilled or on the edge of catastrophic failure as they're smoking so much, but I've never heard of any real damage from, say, +1L overfill for example.

PositronicRay said:
It affects some cars more than others, I overfilled by 1/2 ltr on a 7ltr sump so pumped it out (on the advice of a marque specialist) to the correct level.

A diesel I'd definitely be wary.
On the SL I presume?


Hainey

4,381 posts

200 months

Thursday 22nd June 2017
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I've seen oil overfils of up to a litre more times than i can count but have never seen damage done because of it.

Most modern cars have a sensor that triggers an 'engine service' warning if there is too much in there and it needs dealt with.

PositronicRay

27,010 posts

183 months

Thursday 22nd June 2017
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Krikkit said:
Interesting, thanks guys. I've seen a few cars/vans which are obviously overfilled or on the edge of catastrophic failure as they're smoking so much, but I've never heard of any real damage from, say, +1L overfill for example.

PositronicRay said:
It affects some cars more than others, I overfilled by 1/2 ltr on a 7ltr sump so pumped it out (on the advice of a marque specialist) to the correct level.

A diesel I'd definitely be wary.
On the SL I presume?
Yup 3.2 M104 motor, MB reduced the recommended amount from 7.5l (still in some literature) to 7l so you now treat 1/2 way between max and min as the max iyswim.

The specialist told me these were v sensitive to overfills so pumped a little out.

Heaveho

5,286 posts

174 months

Thursday 22nd June 2017
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Hmm, I've deliberately overfilled mine by maybe half a litre or so when I've done a trackday, no ill effects.

SuperchargedVR6

3,138 posts

220 months

Thursday 29th June 2017
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My Golf takes 4.7 Litres with a filter, but I always just chuck a 5 litre tub in. Never had any problems doing that.