Holes in camshaft seal galley 1996 850

TDub6483 · Post by **TDub6483** » 08 Sep 2025, 13:59

Hello all,
Recently replaced my camshaft seals due to heavy leaking on the timing belt side. After replacing them, I still was losing a lot of oil from the intake camshaft seal. I took it all apart again, and noted some holes near the base of the camshaft on both the intake and exhaust. At first, I thought it might be from the factory to allow oil to go back into the head. Now I’m thinking something is amiss since the camshaft seal I pulled off had a section cut out that matched the hole. Please see attached pictures. I’m not sure how this could’ve happened if it is not from the factory. I always verified timing, and rotated the crankshaft by hand to make sure I had no interference before starting the vehicle.

TDub6483 · Post by **TDub6483** » 08 Sep 2025, 14:19

I forgot to mention the mileage is 250K +
First pic is intake, second pic is exhaust. Third pic is the intake seal, which was replaced 6 months earlier.

crasbe · Post by **crasbe** » 09 Sep 2025, 06:10

I have a spare B5254FS cylinder head that I can take a look at if the holes are present too.

However the section that is missing from your seal is the inner part, not the outer part where the hole is.
It is not surprising that this leaked A LOT of oil and I can't tell you why this happened.

Was the seal still seated or did it move out and the cam rubbed the section away?

Post by **cn90** » 09 Sep 2025, 08:04

The seal folded over during installation.
I posted the details in P80 forum.
Best is to use Corteco brand seal and rotate as you insert it.
Apply a bit tacky red grease on the garter spring before installation.

Also, make a tool to insert to proper depth.

Post by **chrism** » 09 Sep 2025, 09:11

Where’s the missing piece of the seal? Is it lodged in the drain hole?

TDub6483 · Post by **TDub6483** » 09 Sep 2025, 13:46

@crasbe: The seal was seated perfectly, I used a cam seal install/uninstall tool to install and later remove it. There was nothing in the hole. Thinking back, I do remember finding what could have been that part of the cam seal on the frame when I later changed my front main seal and oil pump gasket and O-ring.

TDub6483 · Post by **TDub6483** » 09 Sep 2025, 13:55

@cn90: I used regular motor oil to lube the seal liberally before installing but grease may have been the better route for sure. I do think you’re right on folding the seal on the initial install, as I explained to crasbe, I found a piece on my frame a month or so later doing other seal work, it was covered with dirt and oil, and I wrote it off, but thinking now that was other part of that seal. Appreciate your input, thank you.

TDub6483 · Post by **TDub6483** » 09 Sep 2025, 13:57

@chrism: I think I found it on my frame later, but had no idea where it came from. Pretty sure that was it.

TDub6483 · Post by **TDub6483** » 09 Sep 2025, 14:01

crasbe wrote: ↑09 Sep 2025, 06:10
“However the section that is missing from your seal is the inner part, not the outer part where the hole is.
It is not surprising that this leaked A LOT of oil and I can't tell you why this happened.”

The inner seal would be up against that hole, but as mentioned, I think I borked the original install.
I would still like to know about those holes. The intake hole was much larger than the exhaust hole. It also looked more jagged to me.

Post by **erikv11** » 09 Sep 2025, 15:28

The head comes that way from the factory, with the drain hole. This question used to get posted about once every two months, down to once every year or so now

e.g. viewtopic.php?t=106292