I figure I can fix my wife's car.

2004 BMW 330i. She complained about an exhaust smell, but it looks like just a valve cover gasket leaking onto the exhaust manifold. I bought some plugs since I will be in that area anyway. Dealer wanted $25 a plug. Advance had NGK Laser Platinums for $9 a piece. I bought them because I need something with laser in the name in the BMW, no other reason.

Usually what happens when I do this stuff is I find something else that needs more fixing than I'm prepared to do or alternatively I misdiagnose the problem, but since there is oil staining right below the valve cover I figure I've got it right (it's almost like they put that little ledge in there to show you it is leaking), that and I don't actually smell any exhaust when the thing is running.

Crossing fingers.

Have the wife drive it while you ride and explain EXACTLY when and what shes smelling. Should confirm diagnosis prior to spending money chasing a problem.

I talked with her about it. Smell does not present right away. Then of course there are the pics on the Internet of "BMW E46 valve cover gasket leak" which look exactly like what I see in her car.

I also went under the car and checked for exhaust leaks. The whole thing is stainless so there are no holes and the gaskets are tight.

Mine's overdue for that. You may also want to check under the PS reservoir. Mine leaks at the line out of the bottom of the tank, and smells when the engine gets hot.

I plan to fix both when I'm doing the cooling system sometime next spring.

The failure of the oil separator and attendant plumbing (all conveniently located in the darkest, most remote recesses of the plumbing rat's nest beneath the intake manifold) is often the root cause of M54 motors with leaky valve cover gaskets. As I'm also one who hates to do things twice, I replaced the cyclonic separator and plumbing on my 525iT with an Oil Separator Service Kit I got from ECS. No more leaks but it's begun making an odd chromatically pitched flute/whistle sound lately that's sure to be crankcase ventilation rooted.

So, while the job sucks, if you want to do the gasket once only, suck it up and do the separator.

What the likelihood that the oil separator has clogged at 90k miles? I haven't noticed much oil burning, but then again it doesn't get a lot of mileage put on it. Is there a good way to inspect if things are clogged? Can you get to the hoses that are supposed to be clogged up to inspect them?

I took the hose off the valve cover and took a look in there, doesn't look clogged at that point, but I'm assuming you have to go down deeper to find any clogging? Any other hoses seem buried under the intake plumbing.

The separator is way up under the intake manifold and it has a bunch of accordion hoses routed from it to various locations on the rubber intake boot, manifold, valve cover and dipstick tube. The hoses become brittle and break/crack/leak and the separator fills with sludge and results in a crankcase over-pressure condition which hastens pumping oil out from the lower rear corner of the valve cover, where it drips on to the hot exhaust header.

Here's a photo tutorial on the process: It's a thankless, pig of a job. Seriously. Shops charge an arm and a leg to do it.

is this the same oil separator that in really bad conditions can cause hydro-lock on the motor? I thought I heard something about e46s and x3/5s of the era doing that or something.

I'll have to pull most everything off anyway to do the valve cover so I'll take a look and see if there is clogging. Seems likely at 11 years and 97k miles, but also this is the original valve cover gasket as well.

its the valve cover gasket. Be on the lookout for the coolant, you have between 10k and 50K miles before the plastic that was previously holding the coolant inside the system decides to continuously mist it to the outside of the system. Don't worry, its rarely a catastrophic failure and typically gives you a LOT of time to notice it (like changing much of the engine compartment a different color).
It was quite fun watching my buddies BMW shop, bmw's typically fail is the most amazingly consistent and controlled way.

Eh, this car has been pretty reliable for 97k miles and 11 years. I can list on one hand the major items that have been replaced and most are wear items. It's also the ZHP version of the car so it's a little more tarted up in the performance department.

I've done shocks and struts and brakes once and the alternator went this year, but that's about it.

Yes, as I dig more into the CCV replacement it seems as if everyone hates this job with a passion and it can take around 6 hours for a new person to do.

Valve cover is done and plugs. Man it needed those gaskets, the old ones broke off they were so brittle.

I don't get the CVV parts until Monday so the car is put back together for now.

I setup a monitor with my laptop connected in the garage so I could just have the DIY instructions right there. Got the idea after reading about the GRM 818 build.

I've done the CVV on my wife's E46 330ci. I had to go back in because I managed to pull off a vacuum hose on the backside of the intake plenum between the plenum and the engine. Just make sure that's still attached before you work your way back out!

Just seeing this now. A few points:

-- If you start getting misfires, it's probably the non-original plugs. These engines really don't like non-standard plugs. If the rubber boots were degraded you may want to swap those as well.

-- The CCV system can fail in a few different ways. The hoses can break; the lower one that drains into the dipstick guide tube is the most common. The hoses can plug with oil/water emulsion from condensate; most common with short trips in winter, usually seen at the VC end of the upper intake hose at the 90deg bend. The diaphragm can tear, resulting in uncontrolled manifold vacuum in the crankcase - this is particularly bad if the upper hose is also clogged, as it may pull oil up from the pan via the drain into the manifold. The diaphragm can stick (or more commonly freeze) shut, resulting in no crankcase ventilation. The distribution piece can clog, resulting in no crankcase ventilation. The various o-rings in the system harden and leak, as do the relevant gaskets, resulting in too much flow through the system. The dipstick guide tube drain is a poor design (the part has since been redesigned) and can clog with oil/water emulsion, blocking the drain and eventually forcing the condensate into the intake manifold.

-- Unless you've changed it, your oil filter housing gasket is leaking. The good news is that pulling that part is quick and easy, and gives you the opportunity to clean all the crap out of the alternator duct and gives you much better access to the CCV, so do it at the same time. Probably good to get the intake boots as well, as the small extension that feeds the ICV is probably cracked and leaking.

-- As noted above, at 11 years and 97k miles you need a cooling system. If you are the sort that's checks under the hood regularly you may notice a small leak warning you of impending doom; if you're not, something (probably the expansion tank) will fail catastrophically at the least convenient possible time.

I've done the CCV job more times than I can recall - it is a poorly designed system. The good news is that the job takes about 45 minutes at this point.

The plugs I bought are essentially what the BMW folks use. Even the parts guy at the dealer said they use NGK plugs. The ones that came out look just like the ones I got as replacements. No misfires. All the rest of the ignition system looked fine. Not sure what rubber boots you are referring to, but the coils all looked fine.

I have the oil filter housing gasket along with the CCV parts I just need the throttle body gasket. I got all the CCV parts they recommend on the Turner website other than the oil dipstick guide.

Unfortunately it seems the valve cover gasket was not the source of whatever smell my wife is getting in the car. I have yet to repro the smell. She says it started smelling while idling in the daycare parking lot. I left it idling in the garage for a while and I got nothing. Checked the exhaust itself again and it looks very good overall. I'm going to drive it for a week and see if I smell anything.

I just went over the cooling system and I see no evidence that it needs replacing. I'm not replacing anything on there unless I see something. The only reason I did the valve cover was because I thought it was leaking and I think it did have a small leak. The gaskets were hard and dry and broke off in pieces when they came off. I'm only doing the CCV because I can see some sludge in the spout leading down from the manifold.

If the cooling system fails my wife has AAA and works three miles from the house.

If anything else looks bad when I pull the CCV system I'll go buy it at that point.

Could also just be the drain hose going from the CCV to the dipstick tube.

When I do the CCV I don't replace anything other than the hoses and valve. Throttle body gasket and dipstick o-ring are rubber and re-useable. Might as well clean the t-plate while it's off too.

Make sure you have a good torx set before starting the job. You'll need a torx40 to remove the DISA valve and idle motor. A torx30 to remove the bracket that gets in the way of getting the intake boot off. This can be a real PITA if you don't have a good wobbly or universal 6mm socket. The torx25 will be used to remove the Evap purge valve bracket that gets in the way of one of the CCV hoses.

Make sure you get all the hoses that go to the CCV. Valve cover to valve, intake manifold to valve, valve to dipstick hose, and sometimes you'll need the small hose that T's from the intake hose that runs to the back of the intake manifold.

Luckily I have this job down to about 45 minutes.

Which of you two that have this down to 45 minutes live in CT and want to come by? Everyone else seems to think it takes three hours.

I have a lot of tools. I just never use them. Got all the torx stuff I need and a lot of different wobble sockets and extensions.

I basically have all the hoses that make up the system so I should be fine, if not then I have four cars and can have this one idle if I need to buy more parts.

The coil packs are connected to the plugs by rubber boots that are separate parts. They get dried up and can cause misfires once they get older. If the plugs are the same p/n as the OE plugs you should be good to go with those.

I doubt the smell is from the exhaust itself. If it's not the VCG, it could be a byproduct of the CCV failing. Too much vacuum in the crank plus failed seals will send considerably more oil fumes into the intake manifold; this will be most prevalent at idle, when vacuum is highest.

You can do what you want with the cooling system, but let me explain what happens when an M54 overheats. First off, the gauge is buffered, so once it moves off the center line it's already way too hot. Once it gets there, the chances of not only blowing the head gasket but warping the head is significant. When that head warps, it tends to pull one or more of the head bolts out of the aluminum block, taking the threads with them. This means your most economical option is to buy and install a used engine. A full cooling system refresh is less than $600 in parts and maybe four hours of work. Your call.

Harvey wrote: Which of you two that have this down to 45 minutes live in CT and want to come by? Everyone else seems to think it takes three hours. I have a lot of tools. I just never use them. Got all the torx stuff I need and a lot of different wobble sockets and extensions. I basically have all the hoses that make up the system so I should be fine, if not then I have four cars and can have this one idle if I need to buy more parts.

Sorry, I live in San Diego, can't help you much from here. 3 hours is book time. First time for an amateur can easily take longer with plenty of swearing. I just have the advantage of having done dozens of them.

Another tip-use lube For the hoses of course! True glide or white lithium will help you slide all the hoses on to the valve much easier.

02Pilot wrote: The coil packs are connected to the plugs by rubber boots that are separate parts. They get dried up and can cause misfires once they get older. If the plugs are the same p/n as the OE plugs you should be good to go with those. I doubt the smell is from the exhaust itself. If it's not the VCG, it could be a byproduct of the CCV failing. Too much vacuum in the crank plus failed seals will send considerably more oil fumes into the intake manifold; this will be most prevalent at idle, when vacuum is highest.

The boots looked fine to me. No cracks or dryness that I could see. Everything came out and went back in fine.

Annoying that I can't repro the smell, but I'm thinking it's a good idea that I've decided to replace the CCV. Hoping that cures the problem. I'm betting the CCV has an issue somewhere in there, because she has been driving that short three mile distance to work for a few years now and the car has no time to warm up during the winter.

I live in NY, about 30 minutes from Danbury, but my availability is pretty slim right now.

Lubing the new hose ends is a very good tip (I just spray them with a little WD-40). Mine is to simply break off the old hoses rather than trying to remove them. Way easier and quicker. And pulling that oil filter housing really gives a lot more access to the CCV - if you haven't done the gasket already it's worth it just for the access.

If among your tools you happen to have a slack tube manometer, check the crankcase vacuum before and after. From memory the spec is 4-6 inches of water at idle (which really isn't enough - I can point you to a thread on BF if you want to get deep into the specifics of the problem).

Just kidding, I like doing the work as long as I have instructions and no pressure to get it done in a certain amount of time.

That was the reason I got the oil filter housing gasket, because I was told it's easier to get in there if you remove that and it's cheap to swap the gasket.

I have no manometer.

The car runs fine, makes good power.

In reply to 02Pilot: Yep. My standard procedure on every bimmer that comes through my bay is to check the crankcase vacuum. I use an electronic Dwyer unit and measure in mBar. Specs for the M52/M54/M56 is 16 mBar or less.

Besides saving the customer from future rough running, MIL, or oil consumption, it's also an easy upsell for a gravy job. Win-win.