Confused by oil leak

[ba4x]

Hello fine R3V folk,

Over the last year, I've gotten tons of work done on the e30 with the help of this forum. So far I've managed to get by with lurking/reading/thinking/drinking. The car has come a long way and i'm very grateful for all the archived knowledge online which has helped me. However, with a track day fast approaching and my engine leaking oil, I find myself somewhat stuck and in need of some insight. Searching for my hypothesis has yielded no useful information, which makes me think I'm off in the weeds.

My M20 is leaking oil from somewhere on the front of the engine (maybe the rear, too, but i'll tackle that separately). I got under the car today, cleaned as much as I could, and watched as the engine idled. It seems like oil is leaking down from the water pump, where it meets the block! How does that even make sense? My understanding is that the paper gasket that mates the water pump to the block does not seal in oil, it seals in coolant. I tried tightening the 13mm water pump bolt (seen in the photo), and this actually seemed to slow the leak about 50-75%.

Can anyone make sense of this behavior? I think the front crank seal is fine, since the leak comes from higher up the block. Maybe the leak is coming from ontop of the water pump (cam seal?), and it slithers down around the pump making the illusion I see.

This photo is taken from below, looking up past the oil pan (bits of the oil pan and the front plate which covers the front crank seal are in the foreground). You can see the water pump up there (and the 13mm water pump bolt), and the line of oil which is trickling down directly from it. I did notice some oil appearing on the block above the water pump, but it's hard to tell if it's seeping from the water pump gasket, or coming from elsewhere.

Would appreciate any insight. Thanks. I'll have no problem deleting this thread, hopefully someone can point out the error in my thinking.

PHOTO:

http://imgur.com/9MVfWU9

[Som]

The cam seal is right above the water pump and it's a common area for an oil leak. I can't really get my bearings on that photo, though, to confirm.

I'd guess cam seal or possibly the valve cover -- the rocker plugs are right around/above the cam seal. Those could be leaking, too. I imagine it would be hard to tell without taking the timing belt/cam gear off, though.

You could always start with the easy valve cover gasket/rocker shaft plugs to see if it solves the problem (should be about ~$15 in parts -- valve cover gasket + 4 shaft plugs -- and about 10 minutes of labor). If that doesn't solve it, then it's almost certainly the cam seal.

Unless you're running oil in your cooling system. :)

Som

Edit: If I'm looking at the photo right, you can't really see above the water pump to know if the oil is just dripping from up there and tracing around the water pump and dripping underneath. It does, however, appear that you've at least done some degree of disassembly as it looks like the water pump has a hose missing. If it turns out to be the cam seal, it's not a particularly difficult fix. The only thing is you'll need to swap your timing belt, too -- if you subscribe to the common belief that loosening your timing belt, once stretched, is grounds for replacement. If it's an old timing belt anyway, you might as well replace it while you're in there.

Off the top of my head steps from where you're at. I just rebuilt a head and went through these steps during the swap, so it's pretty fresh in my head -- but I'd still double check with other DIYs.

- I'm guessing you already have the timing belt covers / distributor/rotor off, based on the photo
- Use a 22mm wrench on the crank to rotate the cam gear so cylinder 1 is at TDC. This will be the point where the line on the cam gear lines up with the mark engraved into the head. (Edit: In a previous version of this post, I had the cam/crank ratio backwards -- it's the crank that spins twice for every 1 turn of the cam gear.)
- Keep the 22mm wrench on the crank. While holding this down (or somehow otherwise locking it in place), put an inverted torx socket into the cam gear and remove that bolt
- Loosen the tensioner (2 bolts -- one is the long double bolt/stud), pull the tensioner off
- Pull the timing belt off.
- Pull the cam gear off (and the associated rotor mount / dust shield thing)
- Pull the 2 bolts holding the cam seal housing in
- This can be a not-so-fun part, but you have to remove the metal housing. I just take a punch of a screwdriver in tap the ends to rotate it back and forth, with occasional wedging the screwdriver under the edge to try popping it out.
- Once out, remove both the O-ring and the cam seal itself. Careful not to scratch the groove where the O-ring sits. Also somewhat careful to not damage the inside where the cam seal sits. Also take note of the orientation of the cam seal as you'll install the new one that way, too.
- Clean up the metal housing as best as you can without scratching the groove/inner surface
- Apply a sealant to the inside surface (I use http://www.amazon.com/Permatex-80062.../dp/B000HBGHB8)
- Install the cam seal with even pressure all around the edge -- I think a 32mm socket is what I used here. If I remember right, the orientation here is with the open-end of the seal (that exposes the spring inside) faces the motor, while the flat edge faces outward).
- Apply some oil to O-ring and install that.
- Apply oil to the inside of the seal and reinstall the whole metal housing back into the head. You'll want to apply even pressure when installing this, too. The oil should help it slide on without folding the seal, but tapping it in with the 32mm socket (or whatever the right size is) would be best.
- Put in housing bolts
- Replace cam gear/cover/rotor mount.
- Hand screw in the torx bolt -- but do not tighten!! You don't want the cam turning while the belt is not on.
- If necessary, buy a new tensioner pin/spring and even the tensioner itself. Reinstall. The tensioner is adjustable. What I did here -- and I would do some other research to see if I'm right here -- is I applied as much force as possible on the tensioner and then bolted it down in it's most compressed state. This makes the next step easier.
- Install the timing belt.
- Loosen the adjustment bolt on the tensioner, let the spring place the correct amount of tension on the belt. I wiggled the timing belt a bit here just to make sure the spring was loosening the right amount, but it was probably pointless. Re-tighten the adjustment bolt.
- Put the 22mm wrench back on the crank and hold it in place while you tighten the torx bolt holding the cam gear in place. Since the timing belt is on now, you don't have worry as much about movement taking the cam/crank out of sync and possibly damaging your valves/pistons.
- As a precaution, rotate your crank shaft so that the crank goes through 2 full rotations. You're trying to detect if there's any interference -- which would suggest the belt is off a tooth or more. It's not going to be even pressure as you rotate it or anything, but it shouldn't feel stuck. I've never felt what the interference actually feels like, though, so I can't give any insight here as to what it's *supposed* to feel like if it's interfering.
- Put everything else back together. (love this step) :)

[ba4x]

Thank you Som dude! I really appreciate your insights. The more I read and think about it, the more the cam seals or valve cover gasket looks like the obvious culprit. I plan on doing a valve adjustment soon anyways, that will be a great opportunity to check on the gasket and rocker plug thingys.

The photo is pretty disorienting, I admit it. I took the photo this morning with nothing removed from the engine yet. At the top edge of the photo frame, you can see the main crank pully spinning (blurred from the rotation). In the very top left corner of the frame, you can see a dirty rubber coolant hose connected to the water pump. Anyways, I appreciate you looking at it.

Thanks for the steps for doing the cam seal. I'll try it out after inspecting the valve cover gasket. Would really like to try it this weekend, but I have a special friend visiting for a few days. Now if only I can convince this girl to put on a jump suit and get under the car with me... That's quality time together, right??

[Som]

Haha, well, there's no better way to find out if "she's the one". :)

That said, I'm sure the typical girl advice is "if a guy you like tries to get you to be his garage slave on a first date, dump him". :)

Quick note -- I realized I had the cam/crank gear backwards. The cam position rotates 1 full rotation for every 2 rotations of the crank, not the other way around. I edited my post.

Good luck! (with the oil leak and the special friend) :)

Som