So I'm changing the oil this morning (notice it's a little low) and hear something drop into the oil pan. Come to find out there is a check ball behind the oil filter and it popped out, so I tapped it back in, a little worse for the wear. It apparently regulates pressure to the oil sending unit. Now after doing some research (yes I searched) I find out that most vehicles don't have a part like this, and my mechanic is having trouble even finding a part # for it. ODD. Due to the fragile nature of the part I think I will need a new one so I thought I'd post here before calling Infiniti. Any one out there know of this part/problem or have any ideas? Thanx kindly for reading.

I've never seen it, but thought I read on the forum that the check valve is present in the factory oil filters, but not in aftermarket ones.

i beleive the ball that fell out is not to regulate presure... it is to bypass the filter if it becomes clogged. this way the oil will still b able to pass around the filter to get to the engine......dirty oil is better then no oil........ and yea manuel is right about some filters containing this valve. there are several filters that have no bypass and some that do. usually each size filter has one P/N with the bypass and one without the bypass. if u do try to find the other filter with the valve in it u will need to be sure that the ball is well fixed in place or the oil will not go through the filter......one last note...there should have also been a spring behind the ball. ////O that is what keeps the oil to pas through the filter and not the bypass valve, until the bad case of the filter being clogged.good luck

Thanx tt for your input, I'm going to iron this thing out Tuesday. I'll post my results here.

this is a dead thread, but this topic needs WAY more discussion! Im currently stuck trying to replace one of these "oil pressure relief valve" valves or check valve whatever u wanna call it! There are actually two of these sitting on the oil filter boss where the oil filter screws onto the block... I found the same problem, one is in perfect shape, the other one is..well, destroyed! to say the least...

the Problem im having is 1. access to this is very tight unless you drop the steering rack and lines that are in the way, and a lift would be a big help here. 2. this oil check valve is siezed in the block, can not get it to come out.. has anyone else been here and have a few tips they could share? this ones ugly, the metal is so soft, i can't get a pliers to grab it out. I've tried a reamer to grab the insides of it, no luck.. I tried an oversized plug tap to grab the valve from the inside..no luck.. this is getting bad.. any help guys?

This forum rocks, btw. lots of good info!

Most aftermarket oil filters have two valves in them. An anti-drainback valve that keeps oil from flowing out of the filter back into the oil pan with the engine off to help prevent dry starts, that is, starting the engine with no lubrication. This valve is not necessary on vertically mounted filters mounted upside down as the oil wouldn't flow out of the filter anyway.
A second valve is a bypass valve that lets dirty oil bypass the filter medium if it gets too clogged up with dirt and is stopping the flow too much. When this happens effectively you no longer have any filtering.

I know it has been a while but we ran into the same problem so for future searches the part number is 15241-40F00. There are two of them. we used a 12x1.25 tap, run it in until it bottoms and the piece will spin then pull it out while turning it. tap the new one in and you are set.