4200 GS low oil pressure issue

conaero

Forum Owner
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34,593
I’d replace the non-return valve in the LH cylinder head.

What you describe sounds like variators, perhaps your oil is draining back past that valve.
I agree with Zep, it sounds on start up that you have supply pressure issue to the heads. The non return valve is there to hold pressure in the head during start up.

If it has majorly failed then it could point to your issue but also be prepared that it could be something more sinister I am afraid.

Best of luck mate.
 
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TimR

Member
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2,654
In my estimations, the rattle you hear is the non-return valve itself. Its a ball bearing held closed under pressure by a spring. The spring tires and at start up, the valve bearing slaps about inside the valve body as oil/oil pressure ( in normal circumstances) makes it's way up the dial and motor.... Of course, what this also means is that the oil at the top end has drained down as it's the lack of oil that is the underlying mechanism creating the noise from the valve. They're easily enough replaced. A lack of top end oil on cold start up isnt great though. Thats what the valve is for....
None of this really explains the zero oil pressure....
Hopefully you get it sorted. I agree with others' about NOT running the motor !
 

jmora

New Member
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8
Thanks for all your inputs guys. so I ended up taking the car to the local Maserati dealer and they did a full diagnostic on the issue. It turned out some wiring issues with the 02 sensors causing the problem, it's fixed now and the oil pressure light doesnt come on.
 
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