Oil light coming on when braking.

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Oil light coming on when braking.

43 posts & 26 voices | Started 3 months ago by tails | Latest reply from joao3v16

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tails - Member

The engine oil light is coming on when braking, is the below true.

When you take your foot off the throttle and then you apply brakes it could be an oil pressure issue. Whilst you accelerate you are building up speed and at the same time you are building up oil pressure. The moment you take ya foot off the throttle the oil pressure will drop with the revs .
Whilst the car is stationary and the engine running press the brake pedal a few times, is the light still coming on, remember the oil light is a light with a symbol what looks like an oil can, your brake fluid level light is a light with what looks like this (0) with a quotation mark inside the circle.

Posted 3 months ago #
wwaswas - Member

is the oil pick up at the back of the sump?

could be low oil level and then the oil shifts forward under braking and causes a lack of oil in upper part of engine?

personally, I'd get a pressure gauge on there - it could just be a loose connection somewhere.

does it come on if you brake when statioanry?

other thing to consider is that the brake servo runs off crankcase pressure to a certain extent and as you deplete that it may be causing issues?

Posted 3 months ago #
tails - Member

Your talking way above my knowledge, it only comes on when braking from mid to high speeds, it does not come on when stationary. i will check the dipstick later when the engine has cooled down.

Posted 3 months ago #
derekrides - Member

I'd still check the oil level and colour and no white bits in it (head gasket).

Posted 3 months ago #
sharkbait - Member

i will check the dipstick later when the engine has cooled down.

Nothing stopping you doing it now - sounds like you don't check your oil too often (like me )
I had a car that the oil pressure light would flicker on going around roundabouts - oil was low.

Posted 3 months ago #
molgrips - Member

The very first thing I'd do when my oil light came on would be check the dipstick. The engine doesn't have to be cold - just turn it off and wait a couple of minutes. You can do this by the roadside, and I would - the oil pressure light is not a 'low oil' light, it's a 'omg I have so little oil I can't lubricate myself and could be putting tends of thousands of miles worth of wear on myself in a few miles so pull over pronto and give me oil!"

Posted 3 months ago #
Cougar - Member

Nothing stopping you doing it now

You need to leave it for half an hour after running before checking, so that the oil can drain back into the sump. You'll get an artificially low reading otherwise.

(I think)

Posted 3 months ago #
zokes - Member

You need to leave it for half an hour after running before checking, so that the oil can drain back into the sump. You'll get an artificially low reading otherwise.

THIS

Posted 3 months ago #
molgrips - Member

Not sure it takes half an hour to be honest - most of it will be down in a few minutes. You'll know enough to see if it's massively low or not which is what we are talking about here.

Posted 3 months ago #
wwaswas - Member

Air cooled 911's used to have to be checked with the engine running.

I think a number of yuppies were strangled in the 1980's due to tie/fan interface issues;

Posted 3 months ago #
sugdenr - Member

Check oil level after you have left it. on modern low oil/water capacity cars the light shouldnt come on unless there is literally no oil on the dipstick.

When mine flickers during long sweeping fast corners (coming off on curved motorway junctions etc) I know its time to top up. When it stated flcikering when stationary I realised it was the sensor.

Posted 3 months ago #
sharkbait - Member

You need to leave it for half an hour after running before checking, so that the oil can drain back into the sump. You'll get an artificially low reading otherwise.

I very much doubt it takes that long to drain back down - it would take a couple of hours to top your engine up otherwise.
Modern oils are fairly thin.

Posted 3 months ago #
geoffj - Member

I very much doubt it takes that long to drain back down - it would take a couple of hours to top your engine up otherwise.
Modern oils are fairly thin.

This ^^

Posted 3 months ago #
derekrides - Member

wwaswas - Member
I think a number of yuppies were strangled in the 1980's due to tie/fan interface issues;

:clappyicon:

Posted 3 months ago #
globalti - Member

A flickering oil light on tickover can mean your oil pump is worn, unlikely because it's the best lubricated part of the engine. It might also mean the spring that presses a small valve to regulate oil pressure in the engine is tired and needs replacing.

Posted 3 months ago #
cr500dom - Member

Oil At Operating temperature is about the same viscocity as water....

A minute or so is all you need to get a reasonably accurate oil level,
It sounds like yours is low.

Oil pressure warning lights are normally activated at <5-7psi...... by the time the light comes on its already doing damage

Many late model cars actually use quite a lot of oil in normal use, they need to be checked often.

VW actually specify that 600ml per 1000 miles oil consumption is not excessive
So much so, they will even sell you a little bag to fit in your boot and hold the 1Litre top up bottle of oil !!

Its the price you pay I`m afraid for increasing emmissions regulation focusing on "cold start" rather than real world (Driving) emmissions..... oil has to be much thinnner to reduce the parasitic losses and reduce the thermal mass on start up, for faster warm up

Posted 3 months ago #
cr500dom - Member

derekrides - Member

wwaswas - Member
I think a number of yuppies were strangled in the 1980's due to tie/fan interface issues;

:clappyicon:

Except the 911 was Drysumped.......... and the oil tank was remote from the engine

Posted 3 months ago #
dazz - Member

Does it come on when braking heavily or under normal conditions? Does it come on when you pull away fast?

I repaired a car a while ago where the sensor wire had been catching on something & wore through the outer cable, so it would cause the wire to earth out making the light come on whenever you accelerated or braked hard.

First thing to check is the oil level, as mentioned before

Posted 3 months ago #
globalti - Member

VW actually specify that 600ml per 1000 miles oil consumption is not excessive

No longer. The PD engine on my old B6 Passat burned oil at about that rate but the common-rail diesel on my new B7 Passat hasn't needed any oil at all from brand new to 7,800 miles today.

Posted 3 months ago #
coffeeking - Member

I'd be checking the level, sounds like the pickup is being uncovered due to slosh. Whenever that little light is on you really need to imagine your engine screaming at you Virtually no engine *should* use significant amounts of oil, it's a bad sign for seals of all sorts, but some do tend to do so more than others by design. This is something manufacturers are sometimes willing to accept for other gains but you really need to know if it does and check it regularly. They don't last long with low oil.

Posted 3 months ago #
stumpy01 - Member

globalti - Member

No longer. The PD engine on my old B6 Passat burned oil at about that rate but the common-rail diesel on my new B7 Passat hasn't needed any oil at all from brand new to 7,800 miles today

I think it depends on specific engines. Some seem to and some don't.
My 1.9 PD engine uses barely any oil between services. I used to check regularly, but it never really dropped.
It's now on 180k miles (going in for service & cam belt tomorrow) and I've upped the service intervals to 15k miles as it just sits on the A1 at 1750rpm all the time.

A friend had the 2 litre TDI Golf GT as a company car for a couple of years and that used to chug through oil at quite a rate. He kept a litre in the boot at all times to top it up.

To the OP - initial thought would be low oil. If not that, dodgy sensor.

Posted 3 months ago #
sharkbait - Member

A friend had the 2 litre TDI Golf GT as a company car for a couple of years and that used to chug through oil at quite a rate.

Ours does this.

Posted 3 months ago #
bigyinn - Member

My mums focus deems to like a bit of oil, our Mazda 323 never seems to use any.
I think the key thing is "excessive" consumption or a change in consumption are the key things.

Posted 3 months ago #
coffeeking - Member

My 1991 Toyota uses about half a dipstick (about 500ml) in about 4K miles of hard use with very high oil temps, that's always been the case and it gets an oil change at 4K. The engine has done 160K miles, 30% of those modified to +50% power output.

My 2001 306 HDi never uses a drop.

Posted 3 months ago #
petrieboy - Member

The 1litre top up bottle in my 1.9 A4 lasts me the 20,000 miles between services. Car now has 180k on it, almost all of them chugging along the a1 at 50-70mph

Posted 3 months ago #
brassneck - Member

I wouldn't even bother checking, if the light came on I'd stick a litre in straightaway.

Posted 3 months ago #
imp999 - Member

Bad move, Brassneck.
Overfilling can kill too.

Posted 3 months ago #
wwaswas - Member

I can't bear the tension, how long can it take to check the oil level in one car!

Posted 3 months ago #
coffeeking - Member

I wouldn't even bother checking, if the light came on I'd stick a litre in straightaway.

That would be a mistake also.

I can't believe people get to own cars without any idea of how they work, how to maintain them and basic things not to do.

Posted 3 months ago #
willard - Member

Has he done it yet?

This thread is gripping!

Posted 3 months ago #
willard - Member

On a side note, I used to own an Omega MV6 that would go through a litre of oil in a few thousand miles. No leaks, no blue smoke, it would just go somewhere magically. Then it would throw up a "catastrophic oil level warning" message, that meant that it had dropped to fractionally below minimum.

Add 1 litre of oil, job done.

Posted 3 months ago #
argoose - Member

when was oil changed last, might be old and contaminated and need a change with filter of coarse

Posted 3 months ago #
tails - Member

Wow! 32 replies! You may all sleep easy, I took the S3 back to Vindis Huntingdon and traded it in for an A1, so it is now their problem. The car was too big and powerful for my needs anyway!

Posted 3 months ago #
jonah tonto - Member

got to love the way the oil light is coming on and first stop is not the dipstick but STW i am grinning from ear to ear

Posted 3 months ago #
jonah tonto - Member

cant wait for park two where it takes ages to get the oil in the tiny little hole where the dipstick was

Posted 3 months ago #