Engine oil leak

[FishermanIvan]

My engine has started leaking (at a decent rate) out of the back of the engine, it seems. I can see oil when I look down the right rear side of the motor (from above), the oil is on top of the tranny and some frame bits...

any ideas where this is coming from??

[Randy Forbes]

There is a PRV that screws into the side of the block, with a large screwdriver slot in it. The O-ring has lost its ability to seal.

Replace the whole (pressure regulating) valve, they're cheap enough...

- - - Updated - - -

If you do a search, I'm pretty sure I've posted pics of it before.

[saneesh8]

This PRV is M specific? just want to know..

[Mystikal]

Also called CPV valve. Super common and S54 exclusive.

[FishermanIvan]

Ordered a valve today. $84 in Canada! /anger

Hopefully this fixes it!

[E.Hands]

Good advise here. Constant Pressure Valve. I'd bet that will fix you right up. Mine went out at about 75,000 miles.
In a pinch you could remove it and replace just the o-ring but once you have the bugger out you won't want do it again!

[mreloc]

I love my S52, except when you and I race :/

[gmushial]

There is a PRV that screws into the side of the block, with a large screwdriver slot in it. The O-ring has lost its ability to seal.

Replace the whole (pressure regulating) valve, they're cheap enough...

- - - Updated - - -

If you do a search, I'm pretty sure I've posted pics of it before.

An artifact of the broad rev range of the S54, ie, given a crank driven oil pump, in order to have usable pressure at low rpms, they if it weren't for the CPV, they would have excessive pressures at redline type numbers?

[Randy Forbes]

I love my S52, except when you and I race :/

S-52s have them too, but it's installed in the underside of the head; next to the black deck face. I don't know if they ever fail__they look identical, but I never compared their sizes__but you wouldn't notice it leaking.

An artifact of the broad rev range of the S54, ie, given a crank driven oil pump, in order to have usable pressure at low rpms, they if it weren't for the CPV, they would have excessive pressures at redline type numbers?

I think it has more to do with the pressure differences required between the mains/rods and valve train.

FYI, the S-54 has two (2) more; one inside of each hollow camshaft.

Yes, of course I have pictures...

S-52, might as well get that one right out of the way!











S-54 PRV in the RH side of the cylinder block:







The new one (in the side of the block) ALWAYS lubricate an O-ring prior to installation!



S-54 cams, with individual PRVs; this one happens to be the exhaust side:







The S-54 oil map; #7 is the PRV, the last stop before heading up to the cylinder head.



I know, TMI...

[gmushial]

S-52s have them too, but it's installed in the underside of the head; next to the black deck face. I don't know if they ever fail__they look identical, but I never compared their sizes__but you wouldn't notice it leaking.

I think it has more to do with the pressure differences required between the mains/rods and valve train.

FYI, the S-54 has two (2) more; one inside of each hollow camshaft.

Yes, of course I have pictures...

S-52, might as well get that one right out of the way!

S-54 PRV in the RH side of the cylinder block:

The new one (in the side of the block) ALWAYS lubricate an O-ring prior to installation!

S-54 cams, with individual PRVs; this one happens to be the exhaust side:

The S-54 oil map; #7 is the PRV, the last stop before heading up to the cylinder head.



I know, TMI...

Not hardly [don't think TMI has a meaning to someone that wishes to learn/know]... and many thanks for taking the time, yet again.

[KBH22102]

So my CPV valve is leaking. I have a new one ordered and also an upgraded viton O-ring to minimize the risk of recurrent failure. Most of the procedures I have read about doing the replacement are from the E46 M3 crowd. Those cars seem to have a little more room around the headers to get a tool on it. To any one here who has done it, any pearls about accessing the area? I have a drag link socket coming as well, but it still looks super tight in there and I'm not sure about the best approach to get at this job.

[KBH22102]

Got this done today. First wedge a puck light up above the headers so you can see what you are doing; a head lamp casts too many shadows by itself. I anchored it with some double sided tape. The key to access is removing the small aluminum heat shield on the passenger side above the middle ball joint on the control arm. It is attached with a single 10 mm flat anchor. Once that is off you can reach around the stock header with your right hand and then insert a long handle socket wrench with the drag link socket up with your left hand. Be patient as you can only make about 2-3 clicks with the socket at a time. No oil leaked after it came free.

02A3970E-0B08-4054-8121-EFBB61A389D2.jpegB0A12695-332D-46B0-9D69-A08E3C498685.jpeg2CA20B5E-3346-47B0-B252-B6C1237D9C71.jpeg