Loud tapping noise coming from top of engine

[911monty]

Originally Posted by seningen

hmmm.... Is that a low pressure light?

Is there something about the oil filter canister that has a filter bypass, hopefully that doesn't
bypass back to the sump. someone know for sure?

Mike

The bypass in the filter only opens to bypass the filter media. This is done to prevent bursting the filter housing from a plugged or restricted media and
to prevent oil starvation (It's better to send dirty oil to The engine instead of no oil).

There is however an oil pressure relief valve that limits oil pressure from the oil pump and bypasses back to the sump. It is located on the bottom of the engine. You should check this as there is an upgraded part and it has been known to fail. If it fails open you will experience low pressure.

Living in So Cal you need at least a 40W and possibly a 50 W oil.

[blue62]

Originally Posted by 911monty

The bypass in the filter only opens to bypass the filter media. This is done to prevent bursting the filter housing from a plugged or restricted media and
to prevent oil starvation (It's better to send dirty oil to The engine instead of no oil).

There is however an oil pressure relief valve that limits oil pressure from the oil pump and bypasses back to the sump. It is located on the bottom of the engine. You should check this as there is an upgraded part and it has been known to fail. If it fails open you will experience low pressure.

Living in So Cal you need at least a 40W and possibly a 50 W oil.

911
great info on how the oil bypass in the filter housing works.
I was think that it was the main oil pressure relief valve.

[Dave2001S]

Thanks so much for the helpful comments. I ordered a new oil filter canister with the hope that this may be a simple fix. I also took the step of adding the recommended amount of marvel mystery oil to the crankcase; just to see if there was any improvement. I have run the car only a few times thus far, and not on the road yet. Proceeding carefully, and a bit nervously. Seems to run fine at RPM's up to 3K. No audible tapping, no oil pressure light, no CEL. I plan to change oil and filter again, this time with a 10W40 or 20W50 oil (any suggestion which?). One question: the oil pressure relief valve you mentioned - is that inside the engine? Meaning, in order to check it or replace it, does the engine need to be removed and disassembled? Thanks again for the help.

[911monty]

Oil pressure relief location.

Oil Pressure Relief Valve - 2000 Boxster 2.7l

[Dave2001S]

Thank you. Once removed, is there a way of telling just by looking at the oil pressure relief valve, whether it malfunctioned or failed open as you say?