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oil warning light when heavy braking

Damo

By Damo,
in General Maintenance

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Damo Community Regular

Damo

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I have been practicing my emergency braking lately after getting new pads and machined rotors and have noticed. my oil warning light will flash on for a second. Has anyone else seen this under heavy braking. I guess it is probably normal and nothing to worry about. I hope.

And yes my oil levels are correct.

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BHDave Grand Master

BHDave

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Thats not good, you are getting oil surge.

What type of oil are you running and how hot is the car when you are doing this because i wouldn't expect to have problems as the oil pick up is up the front of the sump and the oil would be sloshing to the front under braking.

Do you have a bent sump by any chance?

Damo Community Regular

Damo

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I am running redline 10w 40 and its happening when engine is at operating temp. Its a pressure light. My sump aint bent either. Has anyone else seen or heard of this happening.

Only happening under very heavy braking and just before i come to a stand still. And only for a second.

froggy Enthusiast

froggy

Posted
Posted

the light that always comes up on my 32 is the funny thing with heat waves coming of it... is that engine temp or something>>?? or the oil one... cus sometimes i'll just be driving and it comes on but it flashes irregularly... then i will restart the car and it'll be alright.. just depends... Can any1 help with this?>

The Dan Grand Master

The Dan

Posted
Posted

I wouldn't worry unless you are unemployed.....a new cat can set you back 3-400.

As for the oil pressure light coming on...I would assume that while the engine is running you would only have 2-3 litres of oil in the sump at any one time, therefore, a VERY hard brake would send this oil flying towards the front. Even though the pickup is at the front, you can still fit 2-3 litres in front of it. I would say that BHDave is correct in saying you are experiencing oil surge. It only takes a split second for it to suck a small amount of air and the pressure drops to zero for a split second after that, hence the light coming on, until regular oil pressure returns.

I seriously think you don't have anything to worry about but if you are, take it to a mech who has an oil pressure guage and get your car tested.

Duncan Grand Master

Duncan

Posted
Posted

Oil surge is pretty simple.....all the oil in a wet sump engine like an rb comes thru the oil pick up in the sump. It is in one place usually at the deepest part.

But as the car moves around (esp under high g forces) the oil can move around so much that there is no oil for it to pick up. Result...no oil to the pump and therefore not going around your engine. eeeek.

There are a heap of techniques to deal with this in Rbs such as bigger sumps, baffles and trapdoors in the sump, restrictors in the oil line to the head, foam in the cam covers, larger oil return galleries.

Under brakes is one of the biggest g forces most cars have, and if there is low oil level yhou might get this problem. I know you said your oil levels are correct which is why I didn't mention this first.

Also could be a problem with the oil pressure sensor? Perhaps get a workshop to add an extra oil guage as a first step if you are sure oil levels are OK.

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