Oil light puzzle...

curious

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Wonder why MB don't have pressure sensors?

Ernie

Possibly because Mercedes regard pressure sensors more likely to fail than a level sensor.

(When the oil pressure light came on my Ducati I enquired at the dealer and was told over the phone 100% the sensor. If you can see oil through the sight window keep riding, ignore the light. The oil pumps never fail!)
 

LostKiwi

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By the time the oil pressure light comes on and you've reacted to it it's all a bit late. The engine will already be toast. As the most common cause of loss of pressure is low oil level maybe they thought to try to prevent issues by alerting before the level dropped to the point of oil starvation.
 

Uncle Benz

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By the time the oil pressure light comes on and you've reacted to it it's all a bit late. The engine will already be toast. As the most common cause of loss of pressure is low oil level maybe they thought to try to prevent issues by alerting before the level dropped to the point of oil starvation.

Agree with this. If the red light comes on damage is already being done. On a lot of the race cars I have built I fit an "early warning" oil pressure switch. You can buy these with various set points, but the idea is they will bring the light on at say 6 or 7 psi, rather than the zero that most factory switches trigger at. The theory being it gives you time to kill the engine before the oil pressure disappears completely. The downside is they will often make the light flicker at idle with a hot engine. Provided you are expecting it this can be lived with.
The best solution is an oil pressure gauge. Mercedes used to fit these, but the r129 is I think the last car from the factory that came with one.
 

ajlsl600

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NO oil pressure switch !!!! ( craig to explain logic behind THAT plse ) i not sure i believe it unless it acknowledges that at 0.7 bar they are not really providing the driver with much in the way of choices..........that being the case they ought to fit a damn gauge !!
 

quinnj3

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Deleted due to re-reading posts.


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d215yq

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I'm sure I read it's because Mercedes already supply an oil pressure gauge so you don't need a light, just a low level warning that means you check the pressure gauge.

I think it has to be warm to work so will come on 10 minutes after starting and then 10 minutes later as the oil gets hot and expands the light goes off and then only comes on up prolonged inclines. I'm not sure if I have a dodgy sender but mine starts to do this at halfway between min and max. So as long as it isn't on constantly I'll just leave it until I can be bothered to top it up a bit... as long as the oil pressure is fine it's OK to drive with the light on (as stated in the handbook)
 


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