paoylin1

what is that valve/spring thing between the two oil drain plugs called? and what is it supposed to do? regulate oil flow? would that cause my check engine oil light to come one only to show that the oil is full? thanks oh it's an 01 996tt tip s

jpflip

Can you be more specific about the location of this thing? There are 4 plugs to reach when you do oil change, one on each turbo one on the crankcase and one on the oil tank….

jpflip

Are you talking about this strange flexible pipe on the oil tank?

RangerDick

You mean this thing to the left of the red arrow? that's the oil line from the crankcase to the oil tank. I think it's finned as a heat sink. Not a spring. I don't think there is anything inside. I imagine JPFlip knows for sure. He's really smart about things like this.

paoylin1

there was a little bolt that shot out cause of the spring, there was a little bit of oil and it was located near the big oil reservoir.

jpflip

The only one I saw that pop out because of a spring was on the crankcase. According to the oil system diagram it is either a safety valve, item #3 or a pressure limiting valve item#7...

paoylin1

sorry it's been raining here. i want to snap a pic. but it does resemble #12 in that diagram.

autobonrun

I bet you removed the oil pressure relief valve like jpflip said. It's easy to do by accident rather than the drain plug. It needs to go back in exact same order. I did something similar once. Different 911 but I'll try to find the link.

autobonrun

It could be the same item.

https://rennlist.com/forums/993-foru...il-change.html

paoylin1

so what does the pressure relief valve do?

Macster

It is there to route too high pressure oil back to the tank or possibly to the intake side of the oil pump, so the rest of the oiling system doesn't experience excessively high oil pressure. The oil filter element, the o-rings of the oil filter housing, even the oil filter housing itself, are at risk of damage if exposed to too much oil pressure.

jpflip

If your look at the circuit above #3 is the relief valve (safety valve) in case of malfunction of the #7 pressure limiting valve (pressure regulating valve)…If #7 fail and cannot regulate the pressure within the system (remember higher RPM = higher pressure) #3 will open and release the oil pressure back to the crankcase. But the oil pressure is regulated by #7 and when open the oil is going back to the reservoir….

autobonrun

This. ^^

The oil/water heat exchanger(#6) is interesting. If the coils of this exchanger ever leaked, you could get mixing. I assume the oil pressure is always higher than the water pressure to prevent water from ever getting into the oil.

jpflip

Imho at idle the oil pressure is really low and if it is really warm outside the pressure in the coolant system is a lot higher,even at idle and it will mix. Either way intact! If you end up with foam attach to your oil cap it is a good indication of coolant mix with oil. You remind me something, when I reinstall this heat exchanger after the coolant pipes welding, I was really cautious because if the o-rings under this cooler are not installed properly you will contaminate the system and you don't want to go back in there after the engine is reinstalled ;-(

paoylin1

if this valve was replaced wrong would it make the check oil light come on? i get it pretty regular lately, when i check the oil it's fine