Scavenge Oil Pump Puking oil

Hi All, I noticed a few days ago oil puking out of the scavenge pump on the drivers side. I have not replaced it yet, but did pick up a new one yesterday. The original part #996 107 021 54 was superseded by #997 107 021 04, which is what I received. I'm learning this pump has several names, oil suction pump, scavenge pump, etc. When the car is running, oil is puking out quickly around the bolts/and cover plate. Appears like quite a bit of pressure. I replaced the AOS about 18 months ago (20k miles). No other symptoms, car was running fine, pulled into garage and noticed oil everywhere. No knocking in the motor, no engine lights, etc. It looks easy to replace, 4 bolts. It is the pump on or near the cam cover on the driver side. I was unable to find data on this issue and thought I would post here for more info. Could there be high oil pressure from somewhere else and this was just the weakest area? Or do these pumps go bad and leak? Any suggestions or just replace pump and see if it continues? 2002 996, tip, cab, C4, 102,000 miles, daily driver. Thanks everyone!!

There is a huge circular seal/O ring on the pump .Maybe it is missing. Measuring the oil pressure with a Test gague is cheap and easy(Harbor Freight $30 !) Have you had the oil filter off recently?

UPDATE: I replaced the suction oil pump or scavenger pump on the drivers side this morning. Cleaned off all the oil from the leak and started fine. Off for a ride, up to operating temperature, no issues. Came home excited, washed/waxed, cleaned the wheels and then noticed a large oil spill (10-12" in diameter). Grabbed a flash light, mirror and peaked up at the pump I just installed earlier. I can see the leak now that it has been cleaned, steady drip right above the suction pump coming from 2" round hole above the scavenge pump. I think it is part of the cam cover, it looks like there should be a cap on it. Either way, I don't know what it is, there is no cap, when the car is running, it starts to drip oil from this 2 inch round indent/hole and onto the suction pump area, ultimately to the garage floor, constant fast drip, probably half a quart in 30 minutes if I left it running. Any ideas?

Are you missing the green camshaft end plug ? Someone forgot to replace it or it blew out(unlikely!)

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Yup. Definitely sounds like a cam plug. I blew one out during one of my first track days years ago. A dangerous situation on a racetrack, or on the street for that matter. The cam plug is more like 1" diameter, but worth checking to see if they are in place.

thanks for the responses. It very well could be that, cam plug. If it is that, why would that plug just blow out? Is there perhaps another underlying problem that would cause that? The constant oil leak/dripping rapidly while the engine is running makes me thing major compression issue. I will look at it more closely tomorrow after work. No leaks at first, but once operating temp, it almost pours out...not really pouring, but steadily large drips.

Search Forum member Dharn years ago he had the same issue.It will blow out the cam plug because there is a newly created jet of engine oil behind it !. If someone uses a cam holding/retaining tool clumsily(when the remove a cam cover for example!) ,they can destroy the metal seal at the end of the hollow camshaft. That creates the problem you have. Hopefully they just forgot to reinstall the green cam plug. No, the metal seal in the end of the cam shaft is not available. You have to make one. No ,you can't just put some new/used camshafts in the camcovers becuse your cam cover is match -machined to your cams. Lets hope it is just the little green plugs!

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No thats not true, You can change new cam shafts. Cyl heads and cam covers are machined to gether.

Thanks for the correction. How do you test to know a new camshaft will be compatible with the paired Cylinder Head and Cam Cover ? Engineers blue ?

Use a micrometer

I do use a micrometer and other Machinist Instruments. In fact ,when I rebuilt my M96 I invested in a entire new set up because the old vernier Aircraft Tech tools were inadequate. The M96 specifies tolerances down to 1/10th of 1 thou ! Good luck replicating measurement that precise onsistently. The ambient temperature ,the temperature of the part and the tool become variables .Mad. But you need way more than just a micrometer to match the 3 parts. Hence the Engineer's Blue hack as a way to help people. I would love to read even the tolerances for such micrometer measurements. In my area , I know of only a couple of places who do such work to a professional standard. Costa Mesa R&D is one . The other issue with the engine in the car is getting the correct torque on the cam cover bolts around the camshaft bearing areas. Access and visibility ! Need a beeper T/W

Quotes source post: 14167791

In my case I had the expansion cap in the end of the cam blow out and this blew out the green cap. You would know if this was the case with our car as there would be a stream of oil coming out of the hole that would empty the engine of oil pretty darn quickly as the cams have pressurized oil in them to feed the journals. However, if one of the green caps came out you would loose oil, but not like if an expansion plug blew out. It should be obvious is one of the green caps is missing. And you can swap camshafts, which are all the same based on the side of the engine and intake and exhaust. It is the cam cover and the head which are matched, so you can't swap cam covers.

O.K. Thanks for the confirmation. in that case I am guessing that Porsche just line bore the head_cover to the cam specs. Sorry, I need to understand things, not just follow the Rules. And I should note that John was correct that a micrometer measurement would be sufficient assuming all M96 cylinder head+Cam cover assys. are line bored to exactly the same spec. In the OP's case it seems hopeful that it was simply a missing green plug.Simple enough.

OK here is an image of the VarioCamPlus engine, which is different from the VarioCam engine like mine. This is the engine that the OP has and you can see that the plug above the scavenger pump is much larger. and the scavenger pumps are different from the earlier engines.