E46 M54

[Milord]

Hi everyone,

I'm currently daily'ing an E46 Touring with an M54 engine (320i spec).
Recently the engine acts a bit off.
- Erratic idle
- Doesn't pull away from full stop as smoothly as it did (feels like it needs more throttle)
- A few days ago it refused to start, however a few hours late it roared to life like nothing had happened
- There's a tiny bit of coolant in the oil (milky substance on the oil cap, nothing on the dipstick however)
- Uses a tiny bit of coolant, I'm sure there aren't any leaks so it must go inside the engine...
- Oily smell in the cabin when I'm stationary (red light,...), more so after I've driven it a bit more sporty


The engine has 160.000km (100.000mi) approx, always had good and timely service.
Model year is 2005, this is important as some minor changes occurred in this last MY of the E46. (Mostly vacuum and dipstick design)
Compression on all 6 cylinders is between 11.6 and 12.2 bars.
No extreme vacuum on the head (like you see in video's on Youtube) I can easily remove the cap with the engine running

Recently changed all coolant pipes and thermostat, as well as a full service, all filters and the MAF sensor.
Also changed the valve cover seals, which did reduce the oil smell a bit.

Apparently pulling the head and doing the head gasket is a humongous job, something to do with VANOS and helicoils...
I'm definitely not equipped to do this myself and local shops are divided between "We don't do M54 engines" and "Thats ok, we'll take your liver/kidney for it"

I was wondering; am I overlooking something?
Is there any other cause that could explain these symptoms?

I really do like this car (first in quite a few I've owned over the past years) but I'm not sure I can justify spending 3/4000 euro's on repairing a 15 year old BMW...

Edit: forgot to mention
- the radiator was also changed a few 1000km's ago
- I've been gazing at my OBC measurements constantly and the car runs between 96 and 99°c

[stealthstylz]

If it turns out to be the head gasket just buy another engine. I've time serted several blocks for people and they never last long, even gone to big serts (bigger OD) or fitted 2 inserts per hole to try and get them into some ally with structural integrity left. They're one of those engines that are OK when they work but aren't worth spending money on.

[slammage]

for some of those faults, id be looking for a split intake boot, from the tb to the maf. or any other split hoses ccv/intake side related. check the intake rubber elbow properly, take it off etc, I would also do a smoke test on it to see that you don't have any intake related leaks . that IME has caused erratic idles, not pulling away smoothly etc.

i'd also get the codes read properly with a proper reader to see if you have anything else amiss.

oily smell I would of done as you say changed the rocker cover gaskets, did you give the engine a good clean also? as could still be a fair bit of oil on the block burning away still? the rocker cover gasket you used sealed well? genuine bmw? have had aftermarket parts fail. BMW are not too bad price wise for spares and very helpful IME

hopefully some of that helps

[Milord]

Another engine is the same cost-wise. A good M54 engine with a year of warranty goes for nothing less than 2500 euro.
Is it truly not worth spending any money on this engine? Even though it only has 160.000kms?

I did visually check the intake for leaks when I changed the MAF, but maybe a smoke test is a more definitive way of testing!
I do own a code reader (generic) and it doesn't seem to throw any codes, bar the odd O2 sensor that plays up when I've been in slow traffic too long.

I did clean the engine thoroughly, and the gasket was genuine BMW, I've been tricked too many times in the past with cheap alternatives failing. These are the kind of parts I buy original!
There's definitely some oil left on the exhaust shield from the valve cover leak, I wasn't man enough to remove this with brake cleaner as the car wasn't completely cold and I didn't fancy a haircut and had nothing else on hand... It's weird though that the smell isn't permanent isn't it?

What baffles me most is that I'm having (at least some) head gasket symptoms yet compression seems ok on all 6 cylinders.

I think I'll just pop it into the shop to have it diagnosed properly and see from there...

Thanks for the replies!

[ChasR]

I'll reply back.

But that milky residue won't be a HG. Almost all BMWs do that unless you always take them for a good run. TBH, quite a few cars do that, especially with short runs ; the condensation can't quite burn off, and BMWs tend to have a labrynth of crankcase pipes which doesn't help matters.

IME, BMWs always take a bit of a while to settle down on the coolant level. They are IME a pig to bleed. I struggled with my E36 323i (M52) and my mate struggled with his E46 328 (M52TU). They did eventually settle, but they were poor.

Your issue sounds more like a vacuum leak, coupled with the coolant system level settling. Have you changed your expansion tank cap, and what state is your tank in?

To rule out the HG I'd personally do a leakdown test. That will show whether the HG has actually gone.

The VANOS isn't too bad to deal with; the key is not to move things (sprockets/units) when you remove them on an M52TU/M54.

As for the oily smell, what torque did you do the cam cover bolts to? Doing a Tight AF or 2 ugga dugga method will result in you having a scrap gasket. BMW state the should only be done to 10Nm. To put that into perspective, that is semi-firm pressure from turning the head of a ratchet, and not touching the handle at all. I've done this on mine and it is fine (an S54)

I've seen a couple of M54s leak on new gaskets for the above reason. They're not meant to be tight.

[Milord]

Thanks for the reply.

Car's booked in for a leak test on Tuesday next week.

You could be right about the condensation though, lately I've only taken it for short drives. Now work has started again and I'm driving it a bit more/further I do notice the amount of white smudge reducing.

Vacuum and CCV rebuild are on the agenda for when the car's back from the shop.

I'm not quite sure how hard I fastened the bolts on the valve cover, but I'm pretty sure it was more than 10nm... 10nm is nothing... I might've over-tightened it a bit then... I'll look into where it's leaking when I tackle the CCV/Vacuum!

[pauly22]

I’ve got a z4 with similar symptoms, same engine, I’ve read the codes and it’s saying air flow meter.

I also have milky residue in the oil cap, but the car hasn’t been used in 2 years.

[ChasR]

Jan 9, 2020 20:20:41 GMT pauly22 said:

I’ve got a z4 with similar symptoms, same engine, I’ve read the codes and it’s saying air flow meter.

I also have milky residue in the oil cap, but the car hasn’t been used in 2 years.

You can PM me with this.

Whereabouts are you? I do have INPA and shortly should have Carly if you need to see some live data. INPA is very good for the live data side of things.

With a friend of mine's; the poor running was down to a badly split vacuum pipe. Someone had been there before as it had a new MAF to TB pipe. His had the M52TUB28 in.

[surprisingskoda]

I know I'm late to the party here but want to suggest some things that are very common that you haven't mentioned, just in case it's not sorted yet.

1. CCV. This system needs replaced, parts are not very expensive. It will be clogged up with that mileage and doesn't sound like it's been done.

2. If there is any leaking around the top, after doing the rocker gasket, also consider that the rocker cover itself becomes brittle and cracks with age and these can often need replaced as well.

3. The oil filter housing gasket, which is currently about £7.50 from BMW, is notorious for also becoming old and hard and leaking. This wont be likely to cause your issues but should be done anyway.

The engine is good, I can almost guarantee that. If it's not, I can also guarantee you that I (or almost any BMW dismantler in the UK) can send you a complete engine for much, much less than €2500!

[alfaboy]

The unhappy idle and occasional non start will probably be either crank or cam sensor failing, the lack of power is a telltale of the same, easy job to sort for £50.
Look under the front of your car, through the bumper, you will probably see the radiator is bowed down in the middle, if so its toast and will be leaking, but not show anything on the floor.
Cheers.
Daz.

[Milord]

Bit of an update is due here:

unhappy idle is resolved with a DISA valve rebuild kit.
According to the shop, there was also something slightly off with the "adaptations" the car makes, these were not reset when the MAF was replaced and that conflicted somehow...

Cooling system had an air pocket, so that's solved, according to the shop these are indeed a pain in the *ss to bleed...

the milky substance on the oil cap is probably condensation, I'm not 100% sure whether full synthetic oil was used on the last service so the engine's flushed now and topped up with full synthetic, hopefully this cures that a bit.

furthermore the rocker cover is replaced again and set to the correct tightness, which hopefully solves the oily smell.

Oil pressure sensor is replaced.

Currently waiting on a new steering rack as that had a little knock in it. Since I don't own a ramp I wasn't too keen on doing this myself, and since it's in the shop anyway...


CCV is something I plan on doing soon!

Thanks again for all the suggestions!

surprisingskoda: I'll keep that in mind! Parts do tend to be cheaper in the UK for some reason!