E46 M3 engine rattle
Discussion
I went along to see a 2003 M3 that was for sale with a friend who had been looking for an E46, the car was very clean and had just over 70K on the clock. Things were looking good until the seller started the engine....it fired up from cold no problem and sounded good until after about 20 seconds a top end rattle started, it only lasted a few seconds then stopped. We all went on a short test drive without any problems and the car drove very well. When we came back we left the car for a few minutes then started the engine again but no rattle. My friend is still keen on the car which seemed reasonably priced but was wondering if he could knock the price down further depending on what the problem might be....any ideas, anyone had this problem before?? It seemed to me to be an oil pressure issue....Vanos???
Yes I understand it's hard to diagnose, I only heard it the once myself. I don't really know how long the car had been sitting.
I know the S54 have a tensioner breaking problem but would that not be a constant noise as it only lasted a few seconds? As I said it started without the rattle then made the noise for a few seconds then stopped again.
I know the S54 have a tensioner breaking problem but would that not be a constant noise as it only lasted a few seconds? As I said it started without the rattle then made the noise for a few seconds then stopped again.
You are thinking of the tensioner pad, not the thing which pushes on the tensioner pad 
.
What happens is that the tensioner (a bolt in the front of the engine) can begin to leak and lose pressure, or just begin to stick with time. As said, it's a bolt with a spring (which becomes harder with oil pressure behind it) that tensions the chain/tensioner pad.
.What happens is that the tensioner (a bolt in the front of the engine) can begin to leak and lose pressure, or just begin to stick with time. As said, it's a bolt with a spring (which becomes harder with oil pressure behind it) that tensions the chain/tensioner pad
.What did the seller say?
Have you looked at the car's MOT and / or maintenance history which may identify problems that have resurfaced which fit the description for example? Or problems not dealt with.
Do the sort of issues you think / others have suggested/ throw up fault codes? not had to act with my M3 but my first E46 had issues and I used a simple code reader (a fiver from Amazon) plus a free android app called torque pro and hit the answers.
When I sold my "ordinary E46" I made a video for possible buyers. Maybe ask the seller to do this and then someone here could give a more informed opinion.
Have you looked at the car's MOT and / or maintenance history which may identify problems that have resurfaced which fit the description for example? Or problems not dealt with.
Do the sort of issues you think / others have suggested/ throw up fault codes? not had to act with my M3 but my first E46 had issues and I used a simple code reader (a fiver from Amazon) plus a free android app called torque pro and hit the answers.
When I sold my "ordinary E46" I made a video for possible buyers. Maybe ask the seller to do this and then someone here could give a more informed opinion.
das2000m said:
So assuming that's the problem it would be an easy fix? Would the noise not start as soon as the engine was started until the oil pressure came up?
Assuming it is the tensioner, yes it is an easy item to change. A large socket and some rags will get it changed quickly.The noise depends on how the tensioner has become faulty. How long is a piece of string? Tappets sometimes take forever to quieten down or become noisy during when the car is warming up for example.
But if the owner has been happy to live with that noise what else has he been happy to live with as an issue? Personally, given that there are loads of E46 M3s for sale I'd look elsewhere. I wouldn't personally make a B line for it due to its low mileage ; there will be other low milers out there. The owners on a car of this age count for quite a bit more IMO and experience.
I personally wouldn't buy a £5 reader myself. On my M3 it read none of the codes and claimed all was well with the car ; it has read other cars before. These codes included:
No. 6 cylinder misfire - It was only running on 5 cylinders and you could feel it : EML was on
Above but with cylinder cutout
Electric fan issue
DSC codes ; these are dead handy for diagnosis.
When a version of INPA is £25 including the lead I know where my money would go
.Edited by SebringMan on Friday 10th March 13:24
Edited by SebringMan on Friday 10th March 13:27
das2000m said:
So assuming that's the problem it would be an easy fix? Would the noise not start as soon as the engine was started until the oil pressure came up?
Had my tensioner replaced last year - Iirc the part was about £170 plus fitting. Had it done then promptly had the HG go so the labour cost got lost in the total. Smuler said:
What did the seller say?
Have you looked at the car's MOT and / or maintenance history which may identify problems that have resurfaced which fit the description for example? Or problems not dealt with.
Do the sort of issues you think / others have suggested/ throw up fault codes? not had to act with my M3 but my first E46 had issues and I used a simple code reader (a fiver from Amazon) plus a free android app called torque pro and hit the answers.
When I sold my "ordinary E46" I made a video for possible buyers. Maybe ask the seller to do this and then someone here could give a more informed opinion.
The Car had 7 months MOT, the service history was fairly good, lately by independents. My mate has seen another E46 and is going to see it on Tuesday. If it's good he'll probably buy it, if not I think he will take a chance on the 1st one.Have you looked at the car's MOT and / or maintenance history which may identify problems that have resurfaced which fit the description for example? Or problems not dealt with.
Do the sort of issues you think / others have suggested/ throw up fault codes? not had to act with my M3 but my first E46 had issues and I used a simple code reader (a fiver from Amazon) plus a free android app called torque pro and hit the answers.
When I sold my "ordinary E46" I made a video for possible buyers. Maybe ask the seller to do this and then someone here could give a more informed opinion.
Thanks for everyone's input.
Smuler said:
What did the seller say?
Have you looked at the car's MOT and / or maintenance history which may identify problems that have resurfaced which fit the description for example? Or problems not dealt with.
Do the sort of issues you think / others have suggested/ throw up fault codes? not had to act with my M3 but my first E46 had issues and I used a simple code reader (a fiver from Amazon) plus a free android app called torque pro and hit the answers.
When I sold my "ordinary E46" I made a video for possible buyers. Maybe ask the seller to do this and then someone here could give a more informed opinion.
The Car had 7 months MOT, the service history was fairly good, lately by independents. My mate has seen another E46 and is going to see it on Tuesday. If it's good he'll probably buy it, if not I think he will take a chance on the 1st one.Have you looked at the car's MOT and / or maintenance history which may identify problems that have resurfaced which fit the description for example? Or problems not dealt with.
Do the sort of issues you think / others have suggested/ throw up fault codes? not had to act with my M3 but my first E46 had issues and I used a simple code reader (a fiver from Amazon) plus a free android app called torque pro and hit the answers.
When I sold my "ordinary E46" I made a video for possible buyers. Maybe ask the seller to do this and then someone here could give a more informed opinion.
Thanks for everyone's input.
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