Please have your rod bearings checked...

[ga41]

I didn't post this before but anyway consider this a public service announcement.

Please, PLEASE have your connecting rod bearings checked on your next service.

At worst you'll see that they're fine and no harm done, only some extra labour costs... If not fine you'll probably be saved loads of grief by having it fixed before it causes more damage like mine did..

Some history. My M Coupe is a UK bought BMW Approved Used 2006 car which I purchased in 2009 with 24-25000 miles and subsequently imported to CY. It's now on about 65-66000 miles, has had all the necessary services and in fact has had them more frequently than strictly required during my ownership as I used to track the car about 3-4 times a year and generally took it on plenty of spirited drives. It has caused me several (unrelated) problems so far but I didn't mind that much. I always paid whatever necessary to have it in 100% condition as soon as something bad happened.

In mid July of this year I took it in for some minor problems, I wanted the brakes re-bled because I felt the brake pedal a bit spongy after the brake master cylinder replacement in early June (one of the problems mentioned earlier) and because my passenger side mirror (the glass part) fell off and I wanted it stuck back on properly!

It was in there for a couple of weeks because I was unable to pick it up due to work and other commitments, anyway I picked the car up from the shop, they didn't even charge me for the trouble as I'd brought in my own brake fluid, and headed back home. 30 minutes of perfectly normal highway driving later I came to a large tunnel. Me being me I decided to make a pull to high revs to hear that glorious straight six bounce off the tunnel walls. I rev-match down to 2nd gear and floor it. 3000, 4000, 5000, 6000 RPM then hit a soft limiter at 6500! That's odd I thought! All of a sudden the engine started sounding very gruff and the engine response went out the window, then loud mechanical engine noises started coming out of the front... Damn... There was a highway exit just then and I stopped to call the mechanic.. I then very slowly made my way back to the garage and it's been there since.

The reason for such a long wait for the diagnose is a combination of the traditional summer holiday season in Cyprus being July/August (there's also a public holiday in mid August) and because my mechanic was right in the process of moving to larger premises...

Anyway they checked it out a couple of days ago and then gave me the bad news. Some of the rod bearings have spun and damaged both the rods and the crankshaft beyond salvaging. He said that the problem must've been going on for some time but we all missed it because the bearings never made any noise before, that because it was a 2006 car (in 2004 there was a bearings recall) he thought it didn't go through bearings as the earlier engines and because we always looked after it so good (frequent oil changes etc) he'd never thought that it would just go like that... I asked if the running of the car after the problem appeared (those 30-40min it took to get it back to him) is what made it unsalvageable and he said no. They told me that usually on cars with scored crankshafts they grind/polish the crankshaft down as necessary to smooth and even it and then fit 0.25mm (correct this?) oversized rod bearings. My crank is too scored for this, they brought in the turner and he measured with a micrometer and said they cant do it on mine.

The options they gave me are: 1) get new crankshaft, connecting rods (BMW sells them as a kit of all six), new rod bearings and bolts. 2) get used crankshaft which we won't know if it'll fit with oversized bearings or not unless it's here to be measured, used rods, new oversized or not bearings and bolts. 3) get a used engine and refurbish it with new bearings and bolts.

Option 1 will cost more than €5000, hence it's out of the question. Options 2 and 3 am now in the process of researching.. I've found a used crankshaft and rods on eBay and have asked my mechanic to check out the ads and tell me his opinion. He's also found a couple of possibilities for engines to buy and are waiting on the price/availability etc.

Basically my engine is f***ed and must now pay a shitload of money to fix it.

TLDR version (Too Long Didn't Read)

2006 car with 66000 miles, some track driving, spun bearings all of sudden with damaged rods and crankshaft. Costs a bunch to fix. GET YOURS CHECKED!!

[ga41]

Well at least my stock engine mounts are in good condition





I didn't take any pictures of the bearings themselves, was talking with the mechanic at that time but you didn't need to be an expert to see that they were f***ed... one of them was even visibly wider than the other due to the high temperatures and friction...

[tomscott]

Holy moly, so sorry about this

it is a pretty big worry tho mines a 2006 too about 8k less milage

Also its a bit of a hassle having the rod bearings checked so might as well replace at the same time but heard of around £5-600

[RubyBlueZ4MC]

That's awful! Sorry to hear of it. I will make a note of it for next service (I'm 2008 however). Thanks for informing. Hope you get it sorted in the most cost effective way.

[mmm-five]

Mine's a 2006 with 93k on it - no noises yet and I wasn't planning on doing this check until I get my engine mounts done next year (as part of my suspension replacement & overhaul).

Although I don't do as many track days as you, and most of my driving is motorway at 80+mph / 3250rpm.

ETA: mine did have a new engine at 23k though - so maybe a 2010 engine has some of these issues ironed out? I hope so otherwise my plans for a supercharger may cost more than I thought!

[ga41]

Thank you all for the encouragement. It'll get fixed but it's very stressful and my finances with all the crap going on out here really did not need something like this to happen...

mmm-five, mine was perfectly normal as well until it went bang. Apparently it was a combination of hard driving, mileage and who knows what else. Maybe tiny defects, maybe, maybe, maybe. Many people said, "they do that...". Well, that doesn't make me feel better you know!! We had a long talk with my mechanic, I asked him was there anything, anything other than actually replacing them already, that we could have done to prevent this and he said no.

To all, my honest advice, save up a bit and budget to have them checked and/or replaced sometime soon. Better safe than sorry.

[ga41]

On the other hand this has given me the opportunity to remember how satisfying it is to try and drive a really slow car fast. Pulling, well trying to pull anyway, to the redline on every gear, rev-matching, heel-toeing and still not breaking the speed limit. Of course with my luck i'm sure this will only end up with me blowing that car's engine as well. If that happens it's a bicycle for me! "Look mum no haaaands!!"

[Bing]

Man, that sucks

Hope it's fixed and you are (almost) breaking the speed limit again soon

Are you not tempted to swap out the engine mounts for better ones anyway while it's all exposed, just to avoid future issues and to improve the 1-2 gear change as has been noted on here a few times ?

[ranski]

Not good news

What's it like sourcing parts in your part of the world, any prolonged waiting time?

[ga41]

Not good news

What's it like sourcing parts in your part of the world, any prolonged waiting time?

Tedious, difficult, slow and expensive! Practically everything has to be shipped in. For example I had to wait 2 weeks for a replacement brake master cylinder!

[ga41]

Man, that sucks

Hope it's fixed and you are (almost) breaking the speed limit again soon

Are you not tempted to swap out the engine mounts for better ones anyway while it's all exposed, just to avoid future issues and to improve the 1-2 gear change as has been noted on here a few times ?

Looked everywhere for aftermarket crankshafts but the only ones available charge thousands of dollars and are upgraded items, like making it 3.4lt instead of stock 3.2. Basically racing items. Con rods you can find relatively easy aftermarket but i'm sceptical unless i see proper, detailed and numerous reviews for similar usage to mine. Most aftermarket con rods are for forced induction conversions for example. With rod bearings you can get, stock, treated or coated (upgraded) items but unless i have a crankshaft i wont know what i'll need, if i'll need oversized for example.

Now as for the gear shift action, i was about to get upgraded engine mounts before this crap happened so it's my future plans as well. Basically i just want to get it back on the road first and then i'll see..

[Simon_P]

Balls What a pain and strange that it didn't show any signs before, letting go. How many other engines have gone like this?

On the positive side I like the second picture of the underside and engine

/Pats warranty

[greddyl30pjg]

I asked if the running of the car after the problem appeared (those 30-40min it took to get it back to him) is what made it unsalvageable and he said no.[/Option 1 will b]

As soon as it started 'knocking' you should have turned her off. Running it with knackered shells would defo have aided in damaging the rods, scoring the crank etc

...& also, correct me if im wrong- but, if say there's an issue with oil starvation (i.e. prob with oil pick up/ pump, ran low due to knackered stem seals or just poor maintenance), the bearings will, in most cases, go relatively swiftly, not over a long period?? Hence checking/ disturbing them with do no good. Best way to avoid knackered shells- check oil/ pressure frequently.

[aquazi]

No chance of getting a set from a scrappy and posted? Cant weigh too much for them?

How about getting it priced from Soper in Lincoln and posted?

[Taz]

i thought the M was a solid engine,maybe not