I use my 3.0i Sport mainly at weekends. E.g this week it sat in the garage from last Sunday night till Friday night. I have noticed since I have had it that when I start it up after 5 or 6 days of in action that a I get a tinny rattle like noise from the engine bay. This will last for very short time and by the time I have reversed out the garage up the drive and put it into 1st and driven off it has gone. Does not come back.
I used the car yesterday and when I started up mid afternoon today, no tinny rattle noise. This is the norm, use it regularly no noise. My brother in law says that it might be something to do with oil draining down in the engine due to in activity. Any views please?
Funny noise
Re: Funny noise
Have you changed the engine oil recently?
And it is also worth replacing the two small 0 rings on the filter housing, as well as the large one.
The oil filter only comes with the large one, but the small ones are available from BMW for a couple of pounds.
And it is also worth replacing the two small 0 rings on the filter housing, as well as the large one.
The oil filter only comes with the large one, but the small ones are available from BMW for a couple of pounds.
Re: Funny noise
It's probably the oil settling and then it disappears once circulated again
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Now: '99 Z3M Coupe in imola red
Re: Funny noise
As far as I know, the timing chain tensioners in these engines use engine oil as an hydraulic fluid to help maintain the tension on the chain. It would seem logical that on an engine stood for a while, there would be a second or two when the tension was not being fully applied. 
In my experience generally, timing chain tensioner systems can sometimes be a casualty of less than perfect oil servicing and sometimes the tensioners themselves can just become weaker although I understand this era of BMW ones to be bullet proof.
In my experience generally, timing chain tensioner systems can sometimes be a casualty of less than perfect oil servicing and sometimes the tensioners themselves can just become weaker although I understand this era of BMW ones to be bullet proof.
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Southernboy
- Joined: Thu 07 Oct, 2010 12:39
- Posts: 6437
- Location: Johannesburg
Re: Funny noise
Hi John.. I had a similar "rattle" with my previous 2.8 at start-up. It is somewhat disconcerting and one imagines ugly things in the making. In my case it turned out to be the front cat just after the exhaust manifold. Seems the innards were past their use by date. As the engine warmed, it stopped due to expansion I was told. I simply had it removed and it sorted the issue.
Having described my cause / cure, I would add a few other areas you might consider. The possibility of a drive belt tensioner should be considered. At start up, the tensioners are placed under unusual pressure since the belt will be stretched as the motor goes from 0 revs to 1700 rpm in a split second.. this will require the belt to "catch up with itself and settle into the rotation. The belt tensioners equally are doing their best to accomodate the belt against the that sudden movement as well as the torque twist of the motor on it's mountings. At no time will these components be asked to make such abrupt adaptations once the motor is running... you can't suddenly increase your rpm by 1700 once you're driving... except on deceleration, by which time everything has settled into running temp mode. If the spring / torque in the tensioners is less than required or their bearings are worn excessively they will rattle, and should be replaced. If you source a Meyle outlet, they are really top quality, and since you're doing them, replace both belts too - Meyle again make 1st rate products there too.
I don't think an engine oil change will do anything to cure a rattle even if it is in the motor... and any rattle would be a constant if it were associated with moving parts in there. It may be caused by a lack of upper cylinder lubrication though... ie. in the cylinder head. That's where all the small moving parts are... like valves, cams, lifters etc as well as the Vanos mechanisms. If the car has been standing for a few days, oil will naturally drain to the sump, leaving the top end "dry" as it were. Oil is supplied to the top under pressure by the oil pump, and in fact there are several small outlets in the upper cylinder head from which the oil literally squirts over the cams, valve shafts and the bearings, gears etc. Once the motor is started and the oil pump is driven (by the crankshaft) oil is forced out over these parts. A rattle from such a situation is to be expected, but only briefly.. ie for less than 10 - 15 seconds.
Bear in mind too, the ECU needs to be provided info from the various sensors to provide correct engine running info for fuel, cam and Vanos positions etc. At the time you last switched off vs the new start up, that info is not a continuous thread. Ideally at start up, you should turn the ignition on and wait some 5 seconds before cranking the motor. This will allow the ECU sufficient time to collect all the info from the sensors to anticipate requirements. The actual time it requires is less than 5 seconds, but given the car has been standing, it may be asleep...
Giving the 5 seconds of "grace" will allow the fuel pump to achieve pressure in the fuel lines, and all the various sensor checks to be registered by the ECU...
Hope the above helps and you find the source... perhaps open the hood and get someone else to start it up so you can listen and try to localise the source...
Having described my cause / cure, I would add a few other areas you might consider. The possibility of a drive belt tensioner should be considered. At start up, the tensioners are placed under unusual pressure since the belt will be stretched as the motor goes from 0 revs to 1700 rpm in a split second.. this will require the belt to "catch up with itself and settle into the rotation. The belt tensioners equally are doing their best to accomodate the belt against the that sudden movement as well as the torque twist of the motor on it's mountings. At no time will these components be asked to make such abrupt adaptations once the motor is running... you can't suddenly increase your rpm by 1700 once you're driving... except on deceleration, by which time everything has settled into running temp mode. If the spring / torque in the tensioners is less than required or their bearings are worn excessively they will rattle, and should be replaced. If you source a Meyle outlet, they are really top quality, and since you're doing them, replace both belts too - Meyle again make 1st rate products there too.
I don't think an engine oil change will do anything to cure a rattle even if it is in the motor... and any rattle would be a constant if it were associated with moving parts in there. It may be caused by a lack of upper cylinder lubrication though... ie. in the cylinder head. That's where all the small moving parts are... like valves, cams, lifters etc as well as the Vanos mechanisms. If the car has been standing for a few days, oil will naturally drain to the sump, leaving the top end "dry" as it were. Oil is supplied to the top under pressure by the oil pump, and in fact there are several small outlets in the upper cylinder head from which the oil literally squirts over the cams, valve shafts and the bearings, gears etc. Once the motor is started and the oil pump is driven (by the crankshaft) oil is forced out over these parts. A rattle from such a situation is to be expected, but only briefly.. ie for less than 10 - 15 seconds.
Bear in mind too, the ECU needs to be provided info from the various sensors to provide correct engine running info for fuel, cam and Vanos positions etc. At the time you last switched off vs the new start up, that info is not a continuous thread. Ideally at start up, you should turn the ignition on and wait some 5 seconds before cranking the motor. This will allow the ECU sufficient time to collect all the info from the sensors to anticipate requirements. The actual time it requires is less than 5 seconds, but given the car has been standing, it may be asleep...
Giving the 5 seconds of "grace" will allow the fuel pump to achieve pressure in the fuel lines, and all the various sensor checks to be registered by the ECU...
Hope the above helps and you find the source... perhaps open the hood and get someone else to start it up so you can listen and try to localise the source...
Re: Funny noise
Thanks for this. Will have agood read later.
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Southernboy
- Joined: Thu 07 Oct, 2010 12:39
- Posts: 6437
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- Location: Johannesburg
Re: Funny noise
A bit more info....
Whilst investigating a totally unrelated matter on my car today, I did some reading up on the various engine front items on the M54 motor. One item caught my attention with regard to your query. The Vanos timing chains behind the front timing chain cover on the motor. Inside there you have Primary, and Secondary chain tensioner as well as chain guides on the opposite side of the chain. These are under spring pressure and one would assume they will be pretty much self adjusting. What is interesting though, is that in reading about these, they are parts which will wear and require replacement on "high mileage" engines. I assume by that it would mean 80,000 miles plus ??
Anyhow, the Primary tensioner is fairly easily replaced since it can be accessed without removing the timing chain cover and all the other bits required to get to it (Radiator, fan etc etc)
It is located on the left side of the cover ( facing the engine from the front end). It is under spring pressure, so will pop out when you unscrew it. I would advise you read up on this tensioner and the requirements to replace it.
Anyhow, the reason for the above is obvious...it could be these chains which rattle briefly at start up since they are also lubricated by the engine oil, and possibly if the car has been standing for any time, the oil in that area drains away to the sump. It seems common sense that this would be the case, since one would like to think that all "old" engine oil is drained when doing a service, and the volume behind the timing chain cover will comfortably accomodate a half litre of oil at least.
So, perhaps when you do a physical check with someone else starting up the motor, you pay attention to that area... unfortunately it is also adjacent to the tensioners which work on the drive belts. But I'm sure these will have a more metallic clatter than the belt tensioners...
Hope this provides some more options to investigate.
Whilst investigating a totally unrelated matter on my car today, I did some reading up on the various engine front items on the M54 motor. One item caught my attention with regard to your query. The Vanos timing chains behind the front timing chain cover on the motor. Inside there you have Primary, and Secondary chain tensioner as well as chain guides on the opposite side of the chain. These are under spring pressure and one would assume they will be pretty much self adjusting. What is interesting though, is that in reading about these, they are parts which will wear and require replacement on "high mileage" engines. I assume by that it would mean 80,000 miles plus ??
Anyhow, the Primary tensioner is fairly easily replaced since it can be accessed without removing the timing chain cover and all the other bits required to get to it (Radiator, fan etc etc)
It is located on the left side of the cover ( facing the engine from the front end). It is under spring pressure, so will pop out when you unscrew it. I would advise you read up on this tensioner and the requirements to replace it.
Anyhow, the reason for the above is obvious...it could be these chains which rattle briefly at start up since they are also lubricated by the engine oil, and possibly if the car has been standing for any time, the oil in that area drains away to the sump. It seems common sense that this would be the case, since one would like to think that all "old" engine oil is drained when doing a service, and the volume behind the timing chain cover will comfortably accomodate a half litre of oil at least.
So, perhaps when you do a physical check with someone else starting up the motor, you pay attention to that area... unfortunately it is also adjacent to the tensioners which work on the drive belts. But I'm sure these will have a more metallic clatter than the belt tensioners...
Hope this provides some more options to investigate.
Re: Funny noise
Thanks again. I will get a mate to listen and try to identify exactky where the noise is as a start.
Re: Funny noise
get someone who knows what a vanos rattle sounds like my mates e46 m3 had similar symptoms his was the vanos was going to be expensive so he px.ed it
Re: Funny noise
Latest on funny noise.
Start up and just normal engine noise. Rev the engine and just a normal increase in revs and engine noise. Engage clutch (no noise) engage reverse gear (no noise). Ease off clutch and rattle noise starts. Dip clutch and it goes. As before after reversing up drive noise almost gone and when in first noise quickly disappear. All over in 20 seconds. If I reverse quickly then noise disapears as well.
Start up and just normal engine noise. Rev the engine and just a normal increase in revs and engine noise. Engage clutch (no noise) engage reverse gear (no noise). Ease off clutch and rattle noise starts. Dip clutch and it goes. As before after reversing up drive noise almost gone and when in first noise quickly disappear. All over in 20 seconds. If I reverse quickly then noise disapears as well.
