Oil pressure relief valve

[chrisg]

Tim to answer your questions: What it does - as the name implies it it regulates the oil pressure within the engine. It's actually very simple a spring-loaded plunger with seals on. Once the oil pressure reaches a set level, it pushes past the plunger and the pressure drops. Most of the time its more like a steady trickle and regulation. What can go wrong - spring inside the plunger starts to fail leading to lower pressure, most commonly though the rubber o-rings at the end of the valve start to perish and it won't hold the same level of pressure. What symptoms you get if it fails - most commonly low or erratic oil pressure Hope this helps, Chris

 

[timmyturtle]

Hi,just wondering for knowledge sake.
What it does
What can go wrong
What symptoms you get if it fails

Thanks

 

[JamesO]

Also seen one stick shut and fire all the oil out of the oil filter seal, with a loud bang.

 

[timmyturtle]

Thankyou for the replies So if i am doing engine work its probably worth cleaning/changing the seals? I currently have 4 bar at idle after a 10 min journey,a little bit more when cold.

 

[robdimond]

There is also a non-return valve in the head (16v only?). I remember a thread on rennlist where a guy got his cylinder head skimmed, a bit of swarf ended up getting stuck in this valve and then the cam seized up due to oil starvation. I think if I ever rebuilt the head I'd be tempted to crank it a bit, remove the cam cover and check there is oil being sprayed about in there.

 

[robwright]

ORIGINAL: timmyturtle Thankyou for the replies So if i am doing engine work its probably worth cleaning/changing the seals? I currently have 4 bar at idle after a 10 min journey,a little bit more when cold.

When hot your idle sould be around 2.5 bar and around 4.5 - 5 bar when cold. Somtimes the valve can stick and cause high oil pressure. Well worth doing for the cost of a new O ring, which you could probably source for pence.