Blind panic. '92 525i

[whiskychaser]

I stop at the ATM on the way home. Start the engine and get a horrible rattling noise. Ok, I've got a lazy cam follower but that quietens down after about five seconds. This is something else! I'm thinking maybe the timing chain tensioner has gone and the chain is hitting the casing. So I drive the quarter mile home with clenched teeth. The car drives absolutely fine. No loss of power and it changes gear fine(5 speed auto). But I have the rattle and there is a definite whir like a bearing picking up. I put it into reverse to back into the drive and the rattle and whirring stops. I stop the engine and restart it. No problems. Its like it never happened. But it did and I dont expect thats an end to it. Not much to go on I know but any suggestions appreciated

PS My windscreen wipers work fine. And I thought Becker was a tennis player :-)

[indierthanthou]

Maybe you had a gremlin in there, banging his tin cup against the bars of your grille.

Sometimes things like this come up and go away for no apparent reason, though I would definitely reccommend checking it out. Try popping off the valve cover if its not too involved (im an m30 man, and an extremely new one at that) and look to see if anything is out of the ordinary. Usually when I have a funky noise that goes away quickly I have to wait till it comes back before I check it out.

And do you have an extra set of 29" spinners i could have for cheap?

[Blitzkrieg Bob]

if you didn't pop the hood, but just heard this noise, it could have been the starter not retracting fully after your start up.

These cars have a plastic bendex lever and they sometimes fail.

[whiskychaser]

Maybe you had a gremlin in there, banging his tin cup against the bars of your grille.

Sometimes things like this come up and go away for no apparent reason, though I would definitely reccommend checking it out. Try popping off the valve cover if its not too involved (im an m30 man, and an extremely new one at that) and look to see if anything is out of the ordinary. Usually when I have a funky noise that goes away quickly I have to wait till it comes back before I check it out.

And do you have an extra set of 29" spinners i could have for cheap?

I just had a good look but did not find any gremlins or tins cans :-( There were no spinners either. But I will keep looking and if I find any spare ones that size you can have them free of charge.

PS Anyone tells you alcohol is not a remedy for shock is mistaken :-)

[whiskychaser]

if you didn't pop the hood, but just heard this noise, it could have been the starter not retracting fully after your start up.

These cars have a plastic bendex lever and they sometimes fail.

I did pop the hood but couldnt locate the exact area of the noise. To be honest I didnt want to run the engine any longer than absolutely necessary. What you say makes a lot of sense. The only real clue I have is it stopped when I put it in reverse. Think that might have cleared it?

[indierthanthou]

I just had a good look but did not find any gremlins or tins cans :-( There were no spinners either. But I will keep looking and if I find any spare ones that size you can have them free of charge.

PS Anyone tells you alcohol is not a remedy for shock is mistaken :-)



that thing with the spinners was a jab at the guy making a big deal about not getting answers...im not nearly as think as you drink i am

[whiskychaser]

that thing with the spinners was a jab at the guy making a big deal about not getting answers...im not nearly as think as you drink i am

I'm a bit more relaxed about the problem now. I know its very difficult to identify a problem from a noise, particularly if its as elusive as this one. But if nothing else this proved a point - there is a wealth of knowledge and humour on this site. And I spent an hour under the bonnet (sorry, "hood") looking for 29" spinners and I dont even have any little ones? :-)

[632 Regal]

I would venture a guess that your motor mounts and trans mounts are bad and the engine shifted and somehow gave you such pleasurable sound, the give away was that it went away after shifting to reverse... that is where I would start inspecting altho the mounts are most likely toasted anyways.


I did pop the hood but couldnt locate the exact area of the noise. To be honest I didnt want to run the engine any longer than absolutely necessary. What you say makes a lot of sense. The only real clue I have is it stopped when I put it in reverse. Think that might have cleared it?

[indierthanthou]

now, why didnt i think of that?

[whiskychaser]

I would venture a guess that your motor mounts and trans mounts are bad and the engine shifted and somehow gave you such pleasurable sound, the give away was that it went away after shifting to reverse... that is where I would start inspecting altho the mounts are most likely toasted anyways.

I know its near impossible to diagnose from somebody's description of a noise. What I can say, is that it wasnt regular -not like a tappet, big or small end. Thats why I thought it may be a loose chain. Think my bedtime reading will be the Bentleys under headings timing chain, camshafts and followers etc. First job tomorrow though will be check the mounts!

[RallyD]

I know its near impossible to diagnose from somebody's description of a noise. What I can say, is that it wasnt regular -not like a tappet, big or small end.

no but if in person it can be quite amusing.
the people I work with know that I am into cars. they come by my wood shop and ask me for advice. I love asking them to make the noise that their car makes and then get them all excited with things like "are you sure its not a chugga chugga clunk clunk" they'll be like, nooooo its a chugga squeak clickity clunk, then I go ooooooo that's expensive. its so much fun. :p

[whiskychaser]

Update: Dont believe its the mounts -there is very little movement when moving from P to D or R. The primary timing chain tensioner is free and there is plenty of tension in the spring. Cant feel or hear the chain hitting the casing either. While its nowhere near as bad as when it first occurred, I do get an unhealthy rattle when revving to about 1500 rpm. This is coming from around cylinders 2-3 and a bit low to be a cam bearing. I think this points to the hydraulic tappets. The valve cover has got to come off at some stage but as I dont have a new gasket that will have to wait a couple of days. Any reason I shouldnt try flushing oil?

[whiskychaser]

Update: Just flushed engine then changed oil/filter. No change to the rattle. Plugs are a nice orange colour. Next job is going to be valve cover off to take a look. Meanwhile - Compression test showed 215-220 on all 6 cylinders. I know thats well above min but would be interested to know how just how good this is?

[gtopaul]

I stop at the ATM on the way home. Start the engine and get a horrible rattling noise. Ok, I've got a lazy cam follower but that quietens down after about five seconds. This is something else! I'm thinking maybe the timing chain tensioner has gone and the chain is hitting the casing. So I drive the quarter mile home with clenched teeth. The car drives absolutely fine. No loss of power and it changes gear fine(5 speed auto). But I have the rattle and there is a definite whir like a bearing picking up. I put it into reverse to back into the drive and the rattle and whirring stops. I stop the engine and restart it. No problems. Its like it never happened. But it did and I dont expect thats an end to it. Not much to go on I know but any suggestions appreciated

PS My windscreen wipers work fine. And I thought Becker was a tennis player :-)

Lots of years ago I had a Corvette that made the same terrible rattling sound in drive and when put in reverse it stopped. Turned out a torque convertor bolt had backed out. Tightened it up and all was well. Crank it up and see if it's louder under the car.

Paul

[632 Regal]

banjo bolts loose causing no oil pressure on the top end?

[DaveVoorhis]

banjo bolts loose causing no oil pressure on the top end?
He's got an M50. No banjo bolts to loosen.

[whiskychaser]

I dont expect thats an end to it.


You know sometimes you wish you were wrong? I wasnt. The horrendous noise returned. This time it didnt go away and was accompanied by a loss of power and an engine that would hardly run, let alone idle. Moved it all of 50 yards to park it and had it dragged home. On the positive side, there isnt a puddle of oil underneath or any con-rods sticking out of the block. My partner says we just broke down. I'm calling it catastrophic engine failure. It has a nice ring to it - more than can be said for the engine. Will just have to start at the top and work down. Any suggestions for a component failure that results in a noise like sawing through a tin of bolts appreciated. Failing that I may be a little while before I post an update :-(

[whiskychaser]

Update: These two pics were taken with number one piston at TDC, one a full turn of the crank after the other. Think the position of the cam lobes on no. 1 cylinder says it all - they should be pointing up and towards each other! Though you cant see them in the pics, the timing arrows on the camshaft sprockets are horizontal instead of pointing straight up. I make that a mere 90 degrees out:-( Propose to fit new chains and tensioners then see if I've still got those good compression figures

[Denton]

Whoa!

[whiskychaser]

Whoa!

I said something more like WTF? Anybody know how to do a compression test without spinning the engine? Only if I havent got bent valves or cracked pistons already I'd like to keep it that way

[Ferret]

You know sometimes you wish you were wrong? I wasnt. The horrendous noise returned. This time it didnt go away and was accompanied by a loss of power and an engine that would hardly run, let alone idle. Moved it all of 50 yards to park it and had it dragged home. On the positive side, there isnt a puddle of oil underneath or any con-rods sticking out of the block. My partner says we just broke down. I'm calling it catastrophic engine failure. It has a nice ring to it - more than can be said for the engine. Will just have to start at the top and work down. Any suggestions for a component failure that results in a noise like sawing through a tin of bolts appreciated. Failing that I may be a little while before I post an update :-(

It ran at all like that?

Man, I got one cam out by just a few degrees the first time I rebuilt an M50 and it took me half an hour to get it to start :o

Shocking, where did the slip happen?

[632 Regal]

low oil pressure can cause the tensioner to limp out on you, perhaps?


Update: These two pics were taken with number one piston at TDC, one a full turn of the crank after the other. Think the position of the cam lobes on no. 1 cylinder says it all - they should be pointing up and towards each other! Though you cant see them in the pics, the timing arrows on the camshaft sprockets are horizontal instead of pointing straight up. I make that a mere 90 degrees out:-( Propose to fit new chains and tensioners then see if I've still got those good compression figures

[whiskychaser]

low oil pressure can cause the tensioner to limp out on you, perhaps?

Firstly, no it didnt run like that:-) It died.
The tensioner on the short chain between the sprockets works fine -it moves up and down freely but that shows the chain is stretched in places. The arrows on the sprockets point in the same direction so the problem is the main chain. I think it is getting hooked up on the tensioner or guide somehow and has jumped off the sprockets. I need to get a tool to lock the cams before I go any further as BMW in their wisdom put two timing chain cover bolts under the sprockets. I also know the crankshaft nut is a pig to shift. Bentleys shows a tool for locking the drive plate but I'm not sure if this is strong enough?

[whiskychaser]

I need to get a tool to lock the cams before I go any further as BMW in their wisdom put two timing chain cover bolts under the sprockets. I also know the crankshaft nut is a pig to shift. Bentleys shows a tool for locking the drive plate but I'm not sure if this is strong enough?

Anybody in the UK know where you can rent/buy these tools at a reasonable price? Kits I've seen so far are VERY expensive. Tks

[Ferret]

Anybody in the UK know where you can rent/buy these tools at a reasonable price? Kits I've seen so far are VERY expensive. Tks

When I had to take the cams out of my M50 I had to use a steel ruler on the square lobes at the back of the cams. This works quite reliably, so long as you check/recheck your positioning about 2 or 3 times after initial setting.

Straight edge set the cam position, turn the crank through two full rotations and double check everything lines up properly, adjust and repeat if necessary.

It takes you an extra 30 minutes, but saves on buying that tool you're only ever going to use two or three times.

[whiskychaser]

When I had to take the cams out of my M50 I had to use a steel ruler on the square lobes at the back of the cams. This works quite reliably, so long as you check/recheck your positioning about 2 or 3 times after initial setting.

Straight edge set the cam position, turn the crank through two full rotations and double check everything lines up properly, adjust and repeat if necessary.

It takes you an extra 30 minutes, but saves on buying that tool you're only ever going to use two or three times.

I dont mind spending half an hour if it saves me over £100 for what appears to be a bit of cast iron. And thats the cheap kit! :-) If you dont mind my asking, how did you lock the crank to get the bolt off? I've jammed a socket and bar and spun the engine before now but clearly I cant do that with a duff chain

[Ferret]

I dont mind spending half an hour if it saves me over £100 for what appears to be a bit of cast iron. And thats the cheap kit! :-) If you dont mind my asking, how did you lock the crank to get the bolt off? I've jammed a socket and bar and spun the engine before now but clearly I cant do that with a duff chain

Lol I cheated and borrowed an impact wrench.

There should be a locking hole in the back of the engine for you to insert something into the flywheel with the engine still in the car. I've never bothered hunting it down yet though so one of the other guys will have to show you a photo of it, sorry!

[whiskychaser]

Lol I cheated and borrowed an impact wrench.

There should be a locking hole in the back of the engine for you to insert something into the flywheel with the engine still in the car. I've never bothered hunting it down yet though so one of the other guys will have to show you a photo of it, sorry!

Impact wrench? Cool! :-) Yes I've seen the tool you mean but I dont think thats for stopping the crank moving while you undo the bolt. I think thats just to stop it moving off TDC while you fit the chains. I would break the end off that and get it stuck in the bellhousing somewhere:-) Will have a look at the pulley - there are probably slots in it to take a tool. I thought of jamming one of the crankshaft webs but really dont want to crack the block while I' at it :-)

[Ferret]

Impact wrench? Cool! :-) Yes I've seen the tool you mean but I dont think thats for stopping the crank moving while you undo the bolt. I think thats just to stop it moving off TDC while you fit the chains. I would break the end off that and get it stuck in the bellhousing somewhere:-) Will have a look at the pulley - there are probably slots in it to take a tool. I thought of jamming one of the crankshaft webs but really dont want to crack the block while I' at it :-)

It should be possible to jam the flywheel through the starter motor mount - some of the other guys here should have good ideas as a lot of people seem to have experience rebuilding this motor.

[whiskychaser]

It should be possible to jam the flywheel through the starter motor mount - some of the other guys here should have good ideas as a lot of people seem to have experience rebuilding this motor.

Yep. Done that with a screwdriver before. But the starter isnt easiest to get at. There are many who will say you can take it out without removing the inlet manifold but I wouldnt even try. Just looking for shortcuts if there are any. Will sort it. Thanks for the support!! :-)

[whiskychaser]

Update: Jammed the flywheel with an allen key and the got the crankshaft bolt loose with a 4ft bar. The tensioner arm on the main chain was a bit chipped but the pic should show what the problem was - a broken chain guide. The broken piece is from the top. The remaining bit was still attached and leaning into the chain links. My guess is it snagged the chain and caused it to jump the sprockets. Will have to see if any 'real' damage is done when the new bits are in and I do a compression check

[whiskychaser]

Anyone replaced the chain tensioner arm on a 525i? You undo a circlip on the bottom pivot but there is no way it will slide off as the top end of the arm pokes through the gap in the head. I am considering sawing the arm in half to remove it:-) That will give me access to the pivot stud. But that hardly helps fit the new one or tighten the stud once it is in.

[632 Regal]

Impact wrench? Cool! :-)

Plan on a 3/4 inch impact here, I heard that you need a 6 foot breaker bar extension to crack em loose. Any updates yet?

[whiskychaser]

Plan on a 3/4 inch impact here, I heard that you need a 6 foot breaker bar extension to crack em loose. Any updates yet?

Sorry but I think you missed my earlier post :-) :
Update: Jammed the flywheel with an allen key and the got the crankshaft bolt loose with a 4ft bar. In fact it came off a hell of a lot easier than others I've worked on.

My problem now is how to get the tensioner arm off - it is so long it sticks through the gap in the head so wont slide off. The pivot 'bolt' appears to be a round stud. The only bit you can get at is where the circlip fits. Tried mole grips without any luck. BMW must fit the arm to the block then drop the head on after!