TurboFocus
TurboFocus Reader
7/23/17 4:05 p.m.

Last week I found an oil leak at the valve cover gasket and fixed it... Ever since I fixed it there has been this smoking issue.
I'm really not sure whats causing this other than a pressurized motor. help?

TIA grm

TurboFocus
TurboFocus Reader
7/23/17 4:08 p.m.

On a brighter note, I replaced the windshield all on my own! Well I enlisted the help of a buddy and my wife... No more giant crack!



oldtin
oldtin PowerDork
7/23/17 7:03 p.m.

engines need a way to release crankcase pressure - usually into a pvc system. Looks like that hose is supposed to connect back to the air filter housing/pcv valve? A little extra smoke could mean a little blow by of the piston rings or valve guide seals. Getting any oil smoke from the exhaust? Have you done a compression test of the cylinders?

BrokenYugo
BrokenYugo MegaDork
7/23/17 7:42 p.m.

Are you sure it wasn't always doing that? Looks like typical tired engine blowby to me, run thick enough oil to keep the oil consumption under control and live with it, or rebuild/replace the engine.

There are usually two crankcase ventilation hoses, one runs directly into the clean air side of the air filter, the other will be connected to manifold vacuum with a PCV valve or small orifice restricting/regulating the flow. This pulls a metered amount of air through the crankcase and burns it in the engine for emissions and oil life reasons. If that's all there and functional (Maybe you messed something up putting the valve cover back on?) and it's blowing smoke out the fresh air hose that typically indicates that the piston rings simply aren't making a good seal anymore (worn rings and bores) and an excessive amount of combustion gasses are blowing past the pistons into the crankcase.

Ransom
Ransom GRM+ Memberand PowerDork
7/23/17 7:48 p.m.

A new windshield is an underrated joy! You don't really notice the slow degradation of the old one (though I guess you noticed the crack), and the sudden clarity (and wiper function) are stunning!

OldGray320i
OldGray320i Dork
7/23/17 9:53 p.m.

If the valve guide seals are bad, usually the smoke will go away after driving the car a few hundred feet (unless they're completely gone), and then start again as you come to a stop.

Where does that normally vent to? I agree looks like it might go back through the air cleaner assembly (i.e. so routing gets you past inspection?)

Re: the windshield, u da man.

oldopelguy
oldopelguy UltraDork
7/24/17 12:32 a.m.

That hose should connect to the bottom of the air filter, inside the filter itself. There should also be a small hose in the valve cover attached to a 1/4" or so nipple on the intake manifold below the carb. The nipple has an orifice in it to draw some of that in; you can check it by hooking up a chunk of small hose and blowing through it.

TurboFocus
TurboFocus Reader
7/24/17 5:21 a.m.

Pictures don't show it since I cleaned it up but it throws so much oil it leaks out of the air filter housing and into the engine bay (which I can get a picture of). Afaik, no smoke coming out the trail pipe.

Couldn't tell you if it's always done this since it only started happening after I replaced the valve cover gasket. Maybe it has because when I got it the bay was so covered in oil that I had to pressure washer clean in for a couple days to be able to find the leak.

Forgot to buy a compression tester tool since one of my previous threads, so no compression test for me. I'll see if my flaps has one, time to test my Deutsch skills a little.

There are two hoses that I see that connect to the air filter, one is the one throwing all the smoke and oil. The other is a little vacuum hose that connects in the same vicinity and goes straight to the IM. Really don't know where they could hide a pcv valve in the motor. Things a pretty basic motor, really nothing to it.

TurboFocus
TurboFocus Reader
7/24/17 5:30 a.m.

I'll admit maybe I messed something up putting the valve cover back on but have no idea how that would happen without me really noticing. The only thing I did when it was off was clean some of the sludge off...

Not quite sure what fresh air hose you're talking about but I'd love to find out how to spot one.

I keep seeing valve guides and poison rings bright up. Is the only way to test piston rings and valve guides a compression test? Or is there a back yard mechanic way of doing it? Like I said earlier I really have no problem doing a compression test, just don't have the tools on me atm.

I'll get more pics of the set up soon for you all, they're worth a thousand words.

TurboFocus
TurboFocus Reader
7/24/17 5:37 a.m.

Also, for those congratulating me on the windshield job, Thank You!!!

E36 M3 was hard to do, spent an hour and a half getting the rubber seal around the window in on our bed; thankfully my wife is cool about it, I did ok with her lol.

Couple days later I have a day off and invite a buddy to help my with the install. Took us 4-5 hours to install it and about 30-50 feet of wire. Freakin wire kept breaking half way through, what bs!

Overall I'm happy with the result. Water hose test shows it only leaks a little, plan on buying some of that glue stuff they used on modern cars and filling in the corners with it.

End result was totally worth it and I saved 200-300 euro from paying some guy to do it for me. Plus that guy pretended to not speak English until he found out I wanted a windshield replaced.

02Pilot
02Pilot Dork
7/24/17 6:55 a.m.

First thing I would suggest is to put a catch can in the system to separate the oil. Ideally this would be plumbed to drain the caught oil back into the pan, but if not make sure it's placed so it's easy to drain.

Second is to see if you've got a pressurized crankcase. With the engine running you want a little vacuum to ensure you're evacuating the fumes (and sludge-forming byproducts of combustion). A slack-tube manometer is easy to build and will show just how much pressure or vacuum you have at various operating speeds.

LanEvo
LanEvo GRM+ Memberand Reader
7/24/17 8:55 a.m.

If the old valve cover gasket wasn't sealing well, isn't it possible that you simply couldn't see all that oil vapor as it was seeping out all over the place? In that case, replacing the gasket might have sealed the top end well enough that all the vapor is now being pushed out the vent tube.

The simplest solution would be to just connect the vent tube to some kind of container (like an old oil bottle) with a length of hose. Measure how much oil is accumulating and keep your engine bay clean. It may help you figure out what's going on.

oldopelguy
oldopelguy UltraDork
7/24/17 10:46 a.m.

Your big hose, the 3/4" or so one in the video, is the fresh air hose and under low load conditions it should allow filtered air from inside the air filter to get into the crankcase. Under higher load conditions, or in cases of excessive blow by air coming out of the crankcase will flow through that tube into the air filter housing where the vapors will be sucked into the engine and you won't even know it's happening except for a little oil inside the air filter.

On the other end of the little bump on top of the valve cover there is a 3/8-1/2" hole. That hole is supposed to have a smaller hose in it. That hose is supposed to connect to your intake manifold, typically to a dedicated small nipple opposite the bigger nipple that goes to the brake booster. Under normal conditions that manifold vacuum draws all those gasses out through the little tube and keeps the crankcase at a slight vacuum, or at least drawing air in through the bigger tube. You don't have an actual pcv valve, just a constant metered vacuum and a constant vent at the same time.

If there is a small vacuum line going to the air filter it's for a preheat tube and should be attached to the same nipple "tree" as the brake booster.

BrokenYugo
BrokenYugo MegaDork
7/24/17 1:04 p.m.
TurboFocus wrote: I keep seeing valve guides and poison rings bright up. Is the only way to test piston rings and valve guides a compression test? Or is there a back yard mechanic way of doing it? Like I said earlier I really have no problem doing a compression test, just don't have the tools on me atm.

Guides are easy enough to spot, a puff of blue smoke from the tail pipe on a cold start is a solid indicator the exhaust guides are bad, or at least on the loose end of spec and the seals (which can be quite crude on an engine this old) have failed. You can check intake guides/seals by running it up to a fairly high RPM on the road, hold that gear and engine brake back down, then floor it again, lots of smoke will come out at that point if the guides/seals are loose (the high engine vacuum will try to pull an excessive amount of oil though the guides and into the intake).

This and bad rings can also be seen on a vacuum gauge, which is a must have diagnostic and tuning tool when dealing with carbureted cars.

TurboFocus
TurboFocus Reader
7/24/17 3:11 p.m.

These are the engine bay shots I promised, everything seems functional at the moment.




While replacing the windshield my buddy and I discussed a catch can device. The idea would be to have it be a vented contained just sitting on top of the tube, so when the motor turns off all the oil drains right back where it came from.
The slack tube manometer seems like just a sealed tube in a u shape with liquid in it? Seems like an easy thing to draw up, does it need to be a certain size for what I'm doing?

That's exactly what I was thinking about the valve cover replacement, now that its sealed its going through the more 'proper' route. Engine still ran fine today but IMHO it's not normal for a motor to be sucking in oil when it should just be gas/air/spark.

OldOpelYoda - You're describing my engine bay pretty spot on but I'm losing you for the vent on the opposite side of the valve cover... perhaps you could use my picture to describe where you're describing. If somethings missing that should be there I'd like to fix it. If you're talking about the small brown vacuum hose in the picture above, that does have vacuum, I felt it suck on my thumb while I was investigating what it did.

Yet another tool I need to add to the collection, I've got to buy a couple BMW parts soon. As long as I remember that I need a compression tester and a vacuum gauge I should be set. If a guide is bad I'm assuming I'll need a new head? Loose rocker arms couldn't have the same effect could they? I did some more research after I shot that video and I think that's pretty normal, just wanted to make sure.

02Pilot
02Pilot Dork
7/24/17 3:25 p.m.

A catch can fitted between the VC and the air filter housing could be a nice neat installation if you find or make the can to fit. You can either baffle the inside or pack it loosely with brass or copper wool (Chore Boy pads work reasonably well).

BrokenYugo
BrokenYugo MegaDork
7/24/17 3:40 p.m.

Rocker arms: Depends on engine design, see the service manual. If it has solid lifters play is normal and should be adjusted to spec, too loose will be noisy, too tight will burn the valves. If it has hydraulic lifters (oil pressure keeps the clearance at 0) it never really needs to be messed with but there shouldn't be any play.

Valve cover venting: Perhaps this will help.

You won't have a PCV valve from the sounds of it, there will just be a restriction on that hose to limit flow. Right now you have gases flowing the wrong way, out the breather, which at idle (when there is plenty of manifold vacuum) would indicate a very worn engine or the PCV hose is missing or clogged.

Metal scrubber pad material stuffed in the fresh air hose would help keep the oil in the engine while letting gases through, just make sure it's plain metal. Don't use the plastic kind, they're loaded with abrasives that will destroy an engine very quickly.

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