[SpYDd]

Hi All, I'm looking for some advise but mainly reassurance if possible please.
I understand this is probably impossibly to diagnose over the interntet but worth a shot if someone has had a similar experience.

I have a Sept 2005 build 330i e90 n52 auto that has covered 75000 miles.

The car has been driving excellently until recently.
I recently had an oil change and around 200 miles later broke down while sitting in traffic, the car was jerking forward a little with the revs bouncing up and down to around 1500rpm for about a minute, then it died. It would crank but wouldn't fire.
I had it towed to a local garage and they diagnosed it as a failed MAF sensor, they replaced it and the car now starts and drives however there is now some hessitation in the low rpm range and 'lifter noise' is now more prominent than it ever was before (barely noticable), however this could be because the car has been sat for around 2 weeks, I drove a few miles and it seemed to quiet down but it is still there and the hessitation is still there, noise seems to be louder where the hessitation is present.

About a week later I noticed the burning oil smell, checked the oil level according to the idrive it lost around 1 bar from mximum.
I checked the engine and it appears there is an oil leak coming from the oil filter housing.

I took it to a different local garage and they agreed with me that the oil filter gasket is leaking, however they are also saying I possibly have a leaking head gasket.
I queried if he meant valve cover gasket and he said no, head gasket because in his opinion "there is oil leaking around the head gasket seal and dripping down the block".
He came up with a theory about a garage trying to fix an issue but giving up
I don't think he has checked or tested (compression or leak down test) or anything else other than his visual inspection of where the oil is collecting so I am taking the car to an indy for a second opinion.

I am suspisious of his head gasket claim, as I believe the oil is dripping from the oil filter housing and also possibly the valve cover gasket and colecting along the head gasket area (the oil is dripping down under the intake manifold, along the front of the engine and also appears to be running down the left side of the engine, it is dripping enough to notice the burning smell in the cabin).
Could this also be a cause of the hessitation? the valve cover gasket also leaking and fouling the spark plugs?

Due to his claim I also checked the coolant and it has droped very slightly from the maximum but is not on the minumum, there has been no smoking and no evidence of oil in the cooland or coolant in the oil as far as I can see.
Could this also be down to the OFHG leaking?

The car also apparently had the water pump changed at some point in it's life by a previous owner but I have had no over heating, smoking or mixing of fluids as far as I can tell.

Do you think my mechanic is jumping the gun on his "head gasket" diagnosis?
I will get a second opinion in any case, just wondering what your thoughts are?

[W37V]

You are probably noticing more things since you had the repair done and are super sensitive as you don't want to get stranded again.

Head gasket is very unlikely. Valve cover leak is super common and typically develops after about 60k miles. Def get second opinion.

MAF typically would not cause the car not to run. Heck, I removed entire intake side (maf, intake, throttle) and car still run with no issues (other than CEL). But it does seem like you got it resolved.

Hesitation on throttle input is common with automatic units - normal behavior. You can get a tune to get rid of it.

OFHG is also common - do get it resolved as it can cause your serpentine belt to fail. If you are handy at all, you can do it yourself at the time of next oil change. It takes about 30 min or less.

[smass]

06 N52 have a common issue where an odd external "head" bolt breaks and causes oil to leak up the remaining threads. It is just behind the OFHG. See figure 1 in link below. It is called a head bolt but it does not clamp the combustion chamber. It clamps the area around the timing chain. Thus you can replace the $6 bolt and the oil leak is fixed. The intake manifold needs to be loosed and pulled back an inch or so. Then the old bolt stud can be spun out with a pick. Post a pic of the area under the #1 intake runner and we can check for the broken bolt.

https://www.pelicanparts.com/BMW/tec...lt_Testing.htm

The new bolt will come as a kit with 4 bolts. The 3 other head bolts are inside the valve cover. These do not break as often but I was one of the lucky ones. Here is what I did to change all 4.

https://www.bimmerfest.com/forums/sh...d.php?t=958844

[SpYDd]

Thanks for the replies.
Car is still with the mechanic who is adamant that the head gasket is blown.
He suggested I return it to the dealer (under the consumer rights act UK) for them to sort and are refusing to do any work on the car incase of any further problems and fall back on them.
I am currently negotiating with the dealer.
I asked them how the head gasket could fail without any overheating or smoking, it also idles fine?
They advsied that the head gasket is leaking oil and coolant externally.
They advised that it feels like it is down on power (hence hessitation) and the lifter sound I described sounds like an exhaust leak to them (which they advised is a head gasket symptom).
When I asked to hear it, it does sound exactly like this under accelleration (louder than the typical lifter noise) -

They advised that it is 100% not the valve cover leaking but the oil filter housing is leaking also.


What are your thoughts on this? how probable is it for a car to be seemingly 100% fine one day and external head gasket leak out of nowhere? Could this be something that was developing over time without other symtoms?

I could by the valve cover gasket leaking and them misdiagnosing it as head gasket but the power loss and sound make me second guess.

The dealer also doesn't believe their diagnosis, in his opinion I wouldn't have been able to drive at all without other symptoms.

[W37V]

Did you get second opinion from any other shop? Dude, just pay an hour for a good speciality shop to check it out. Heck, any good competent mechanic should be able to to it. Let them check compression. It should take no time to do it - it's not a diesel.

[SpYDd]

Hello,

Had the car taken to a specialist, they diagnosed the oil leak coming from a snapped head bolt.
Still waiting for the full report.
Does anyone know if the snapped bolt can be replaced, or would the whole head gasket need to be replaced at the same time?
Thanks

[smass]

Originally Posted by SpYDd

Hello,

Had the car taken to a specialist, they diagnosed the oil leak coming from a snapped head bolt.
Still waiting for the full report.
Does anyone know if the snapped bolt can be replaced, or would the whole head gasket need to be replaced at the same time?
Thanks

If the head bolt that broke is outside the valve cover, it can easily be changed. Many people with 2006's have done this without full gasket replacement. The intake manifold bolts need to be removed so the manifold can be pulled back an inch or so at the front edge. The broken bolt remains spin out easily with a pick. The new bolt kit is part # 11120392547. You probably only need 1 of the 4 bolts. The other 3 are inside the valve cover under the timing chain.

Some shops will say that replacing the head gasket is required however this has been proven incorrect many times. This issue only happens to 2006 N52 engines so many shops may not be familiar with the details. I replaced my bolts 3 years ago and I am still leak-free. Feel free to ask more questions.

[SpYDd]

Thanks smass you've been a great help.
I spoke to the specialists today, they confirmed that the bolt that has snapped is the one near the oil filter housing.
They haven't removed the valve cover to check the others as they seem to think removing the valve cover is a complicated job.
I asked them if they can extract the bolt and replace it and they said no...They said they will need to remove the head, pressure test the head, skim it, re seat the head and bolts and also replace the valve seals if necessary.
They confirmed the bolts are the front aluminium bolts and the head gasket has not been compromised.
Seems like overkill to me if the head gasket has not blown, what do you think?

[smass]

Originally Posted by SpYDd

Thanks smass you've been a great help.
I spoke to the specialists today, they confirmed that the bolt that has snapped is the one near the oil filter housing.
They haven't removed the valve cover to check the others as they seem to think removing the valve cover is a complicated job.
I asked them if they can extract the bolt and replace it and they said no...They said they will need to remove the head, pressure test the head, skim it, re seat the head and bolts and also replace the valve seals if necessary.
They confirmed the bolts are the front aluminium bolts and the head gasket has not been compromised.
Seems like overkill to me if the head gasket has not blown, what do you think?

Find a new shop. What they want to do is complete overkill. Replace valve seals? Really? I don't think anyone has had those go bad. Also, removing the valve cover is not a complicated job. At some point, you may want to check under the valve cover for other broken bolts but these are rare. But for now just find a shop that can loosen up the intake manifold to make room and removing/replacing the broken bolt. It takes less than an hour.

[SpYDd]

I’m looking for another Indy now, just had this reply from the current shop:

Thank you for your email, please costs for removing the cylinder head in order to drill out the snapped head bolt.
Cylinder head removal - £1,518.31 (parts and labour)

I have spoken with a technician following our conversation earlier today to see if there could be another way to drill out the snapped head bolt. We could possibly be able to do this however we cannot guarantee this. We would be required to strip intake manifold from the engine in order to gain access to the area of the snapped bolt before attempting to drill out the bolt.

I have taken a quick look at BMW Standard times for removing the intake manifold in order to piece together a rough cost for carrying this out. Provided nothing else would be required, removing the intake manifold and drilling out the snapped head bolt would take approximately 4 hours, doing so you would need to replace the intake manifold gasket, replace the snapped bolt (only available as a set). I have not been able to as yet price up the parts required to carry this out however labour would be a minimum £312.

[smass]

There is no need to drill out the broken bolt. The oil is leaking up the threads now so it is well lubricated. It will easily spin out with a hand pick. This can be done without completely removing the intake manifold. If the front edge is pulled back a couple of inches, you have easy access to the broken bolt.

[SpYDd]

Hi, thought I'd come back with an update.
Things got left for a while while thr country went into lockdown and the garage who had my car closed for the duration.

Anyway. I have the car back and all is well, almost.

Had a word with the garage and showed them the info in this thread and they agreed.
They managed to get the headbolt out with a pick and replace it, no problems.

With regards to the rough running.
This horrible noise seemed to be related to the car being sat for over a month and was cured by getting the car upto temperature and I believe the lifter bleed proceedure.
It sounded horrible before but now sounds completely normal.

The car dying in traffic with every error code possible was battery related.
Changed the battery and all codes gone.

However, the problem that occured before the breakdown reoccurred.
On a cold start the cars idle would either bounce wildly or the car would stall and take 3 attempts to start normally, the idle would still fluctuate till it was warmed a bit.
I could mitigate this by lightly tapping the accelerator for a few seconds until the revs settle to a normal idle.
The indy tested it and described it as the car lurching badly in drive or reverse but when I checked it appeared to only happen in park or neutral, with drive and reverse being a big enough load to even out the idle.
This turned out to be the eccentric shaft sensor.
The car wasn't giving any codes but they advised that when checking the values they were out of spec apparently.

so we did the following,


Changed head bolt
Changed Valve cover gaskets (this was confirmed to be the point of leak, not the head gasket as the original garage advised)
Replaced the ESS.
Transmission service.
New tyres all round.
Front suspension bushes.
Rear brake lines (only begining to slightly swell but might as well while we're at it).
Replace lower steering shaft.
A stearing bearing (I think, not sure on this one at the moment, they called it a stearing bearing and they showed me while still on the car, it was not in good shape and was causing an insanely wide turning circle and skip in steering).
Powersteering fluid flush.
Break fluid flush (old and discoloured).
Car already had brand new suspension springs installed.

Car now when warm sounds great and idles really smoothly when warm, can bearly tell the engine is running.
However there is a new issue...

On a cold start the car shakes a bit (not sure if this is missfire?), the idle is nowhere near as bad compared to pre ESS change, only occasionally hunting 50-100 rpms's or so and once it's warmed up it is totally fine.
The car has once, after being sat for 24 hours taken slightly longer to fire than usual, cranks for maybe 3-4 seconds.
Flat spot/hessitation pulling off from a stand still. This doesn't seem to happen everytime, but most of the time car feels slow and down on power in the low rpm range (seems to cause a jerky gearshift from 1-2 from the AT) then it springs into life and appears back to full power over 2k RPM.

Had the indy look at it, the car is not showing any fault codes (yet).
The tech agreed that the problem is there (actually described the symptoms with only being told the symptom is 'rugh running').
However the owner disagrees, he took the car for 2 days to test and says he can't see anything wrong.
Weird.
The car pulls fine over 2K RPMish and the idle is smooth as silk when warm.

Any ideas?
I've been leaning towards spark pugs, coils, vanos solenoids or injectors?
I want to get this sorted by I'm hessitent to through money at finding the fault, should I wait to see if it eventually throws a code?

[SpYDd]

Thanks again for your help smass!

[HydroxFrost]

About the jerky 1-2 shift and slight hesitation you're experiencing now. After I did my transmission service, my transmission took 6 quarts and appeared full, ended up having to add a quart a couple days later. You might find yourself needing to do the same. Do you notice a rattle at all in the low range? One of your DISA flaps could be failing but they'll only throw a code if the actuator is bad, not the flap is physically damaged a little, but it would cause your symptom. My car was doing a rubber banding type of thing a long time ago and it went away with new plugs, threw some new coils on after a while preventatively and it restored some good power as well.

Originally Posted by SpYDd

Hi, thought I'd come back with an update.
Things got left for a while while thr country went into lockdown and the garage who had my car closed for the duration.

Anyway. I have the car back and all is well, almost.

Had a word with the garage and showed them the info in this thread and they agreed.
They managed to get the headbolt out with a pick and replace it, no problems.

With regards to the rough running.
This horrible noise seemed to be related to the car being sat for over a month and was cured by getting the car upto temperature and I believe the lifter bleed proceedure.
It sounded horrible before but now sounds completely normal.

The car dying in traffic with every error code possible was battery related.
Changed the battery and all codes gone.

However, the problem that occured before the breakdown reoccurred.
On a cold start the cars idle would either bounce wildly or the car would stall and take 3 attempts to start normally, the idle would still fluctuate till it was warmed a bit.
I could mitigate this by lightly tapping the accelerator for a few seconds until the revs settle to a normal idle.
The indy tested it and described it as the car lurching badly in drive or reverse but when I checked it appeared to only happen in park or neutral, with drive and reverse being a big enough load to even out the idle.
This turned out to be the eccentric shaft sensor.
The car wasn't giving any codes but they advised that when checking the values they were out of spec apparently.

so we did the following,


Changed head bolt
Changed Valve cover gaskets (this was confirmed to be the point of leak, not the head gasket as the original garage advised)
Replaced the ESS.
Transmission service.
New tyres all round.
Front suspension bushes.
Rear brake lines (only begining to slightly swell but might as well while we're at it).
Replace lower steering shaft.
A stearing bearing (I think, not sure on this one at the moment, they called it a stearing bearing and they showed me while still on the car, it was not in good shape and was causing an insanely wide turning circle and skip in steering).
Powersteering fluid flush.
Break fluid flush (old and discoloured).
Car already had brand new suspension springs installed.

Car now when warm sounds great and idles really smoothly when warm, can bearly tell the engine is running.
However there is a new issue...

On a cold start the car shakes a bit (not sure if this is missfire?), the idle is nowhere near as bad compared to pre ESS change, only occasionally hunting 50-100 rpms's or so and once it's warmed up it is totally fine.
The car has once, after being sat for 24 hours taken slightly longer to fire than usual, cranks for maybe 3-4 seconds.
Flat spot/hessitation pulling off from a stand still. This doesn't seem to happen everytime, but most of the time car feels slow and down on power in the low rpm range (seems to cause a jerky gearshift from 1-2 from the AT) then it springs into life and appears back to full power over 2k RPM.

Had the indy look at it, the car is not showing any fault codes (yet).
The tech agreed that the problem is there (actually described the symptoms with only being told the symptom is 'rugh running').
However the owner disagrees, he took the car for 2 days to test and says he can't see anything wrong.
Weird.
The car pulls fine over 2K RPMish and the idle is smooth as silk when warm.

Any ideas?
I've been leaning towards spark pugs, coils, vanos solenoids or injectors?
I want to get this sorted by I'm hessitent to through money at finding the fault, should I wait to see if it eventually throws a code?

[SpYDd]

I just scanned the car with my generic Bluetooth scanner and I have 2 codes P1024 Valvetronic (VVT) Self-Learning Function Faulty Lower Learning Range (Bank 1)
one pending and one confirmed.
Edit: Carly shows it as 2A39 Valvetronic, adjustment

[HydroxFrost]

I'm assuming your mechanic isnt a bmw specialist and when he took off the valve cover he didn't reset the valvetronic motor (I believe you need ISTA to do so). That there would cause the code unless something involving the valvetronic motor was physically broken, check the connections as well because we all overlook small stuff from time to time.

Originally Posted by SpYDd

I just scanned the car with my generic Bluetooth scanner and I have 2 codes P1024 Valvetronic (VVT) Self-Learning Function Faulty Lower Learning Range (Bank 1)
one pending and one confirmed.
Edit: Carly shows it as 2A39 Valvetronic, adjustment

[bluewater328]

I think you have the ZF tranny, so it may not necessarily apply. But 1/2 AT shift issues were common for the GM tranny. The official solution was an $40 additive to your ATF from BMW. Actually did the trick for me. That additive is no longer available, but many have had success with Valvoline Max ATF. Another additive that people say worked sufficiently (but sometimes temporarily) was the following:

https://www.amazon.com/Lubegard-1961...370357&sr=8-17

[SpYDd]

Just an update on this, car went back into the Indy to diagnose.
I asked if they did the relearn procedure and they did but after a few days it seems it was forgotten by the car.

They found some corrosion on the Valvetronic and DME harness (and DME itself).
They cleaned off the corrosion and did all the relearn in ISTA etc.

The car now drives great, no jerky gear change and no hesitation or flat spots at all and my mpg’s have increased greatly. The car feels smooth and it’s quiet when idling. I’ve been driving it about a week now and the difference is night and day.

However I’m still getting the rough idle and shaking on a cold start.
It doesn’t seem to do it every time but when it does the symptoms are a slightly longer than usual crank, rough idle for a few seconds until it settles down to normal idle speed and what feels like a side to side shaking or wobbling that can be felt by driver and passenger.
All the symptoms go away after a few seconds and the car drives and starts fine for the rest of the day. After sitting overnight the symptoms return.
I tested the other day by pressing the start button without my foot on the brake, wait about 1 minute and then it starts normally it seems.

Interestingly we discovered the car has a DME from an e60 in it.
I had a fault code for the Ebox fan that was cleared by cleaning the corrosion.

Do you think the symptoms I am having are related? Or something else?
Guessing the next step is to replace the DME and harness.

[lowrydr310]

Originally Posted by SpYDd

However I’m still getting the rough idle and shaking on a cold start.
It doesn’t seem to do it every time but when it does the symptoms are a slightly longer than usual crank, rough idle for a few seconds until it settles down to normal idle speed and what feels like a side to side shaking or wobbling that can be felt by driver and passenger.
All the symptoms go away after a few seconds and the car drives and starts fine for the rest of the day. After sitting overnight the symptoms return.
I tested the other day by pressing the start button without my foot on the brake, wait about 1 minute and then it starts normally it seems.

I have a 2006 330i and it has the exact same issue except the long cranking. Cranks quickly and starts immediately, but it's rough for a few seconds bouncing around then stabilizes and I can feel that slight side to side shaking for about 10 seconds then it's fine.

I also have a 2006 325i and that car starts up and idles perfectly fine.

I going to start with simple stuff, first trying a can or two of injector cleaner snake oil. I've never believed in that crap but it's worth a try. Then:
Smoke Test for air leaks
Clean and swap VANOS solenoids and check valves
Reset adaptations
Coils and plugs

I'm also getting an intermittent lean mixture code on bank 2. So far in my diagnostics I found that the bank 2 downstream (post-cat) O2/lambda probe does not respond as quickly as the other bank's sensor. O2 sensor data isn't used until the engine is warm (starts in open loop) and that lean code is ONLY triggered at idle RPM (confirmed with freeze frame data) therefore I may have a small air leak causing this idle stumble.

Have you checked for any air leaks?

[SpYDd]

Car has started throwing the p1024 Valvetronic Adjustment Range error again.
No engine light, just thought I would give the car another scan.

Car still seems to drive fine except for the cold start issue.

So far we have replaced the eccentric shaft sensor and cleared up the bellow corrosion on the plugs in the eBox.
Can anyone identify the plugs below, look like they are from the VVT or DME resistor and the DME?
Can these plugs be salvaged or replaced?

The indy cleared the corrosion off but the problems returned a few days later.
The only parts we haven't replaced yet are the VVT motor (they think it's fine), the DME or the engine harness.

Engine harness isn't too expensive but the labour will be a killer along with the valve cover again.
Might just cut my losses at this point.

[SpYDd]

Just posting an update in case it can help anyone else in the future.
The problem has been resolved for a few weeks now.

My Indy replaced all of the corroded plugs on the harness and updated the DME.

This has cured all of the problems so no more:
Cold start problems.
Long crank.
Rough idle, car shaking.
Acceleration flat spot.
Jerky gear change.

Everything has been working normally so far and it drives like a brand new car.