Hi Paul, I tried sending you a message but it wouldn't let me, so hope it's ok to ask you a question here.

 

I remember from ages ago that you work with Mercedes' so thought you might have come across this problem before.

 

I've got an SL55 AMG (I bought the one that I started a thread about ages ago, Clarkson's old car) which has an intermittent fault. Most of the time it's perfect, but occasionally the throttle becomes unresponsive, like it's gone in to some sort of safety mode. It happens after a short blast, no warning lights come on, it just won't accelerate from say 70 or what ever speed it's doing, but will still change gears. There's no coughing or chugging, I don't think it's a mechanical fault.

 

It lasts for about a minute then it's fine again. A mechanic friend suggested plugging it in to a laptop and searching for error codes.

 

The car's on 92k miles, full Merc service history, last service 1k ago. Any ideas would be appreciated - Thanks!

I googled leakdown test, I wonder if they'll do that, or they might just think whatever it shows it'll have to be stripped down anyway?

 

I think my mates theory with the cam lobe is that if the inlet valve doesn't open much then there won't be much air being drawn in to compress, whether it works like that in practice though...

 

The guy I bought the car from bought a newer SL55, and a week after having it it started making a horrible tappet noise. Mercedes WSM fitted new tappets on one bank. I just googled hydraulic followers to try and learn something about them, perhaps my problem will be linked to a faulty tappet?

 

Anyway, thanks for your input, I'll post on Tuesday what they've diagnosed...

 

Gonna have a look in the for sale section now, see if there's any nice Zed's around :)

Bad news today - Mercedes WSM have diagnosed a cracked piston. How that can happen I have no idea?

 

They estimate around 7k to replace the piston, but tbh I actually begrudge paying them £132 per hour (around 1k per day) I think that takes the piss lol.

 

So I have 3 choices:

 

1, Let them do it for 7k possibly more.

 

2, Take it away and let a local garage who charge £40 per hour do it (plus Mercs charge so far for stripping it down).

 

3, Sell it as it is. It's in fantastic condition, not a single ding on the bodywork, everything works (apart from the engine haha), FMSH with all invoices. 5k worth of extras including nappa leather and keyless start/go.

 

What d'you think it would fetch on ebay if I sold it as is? I'm thinking that it could be a bargain for someone who could do the work themselves, the parts aren't much- a piston at £300 and a gasket set. What would you do paul? Thanks! :)

Bad news today - Mercedes WSM have diagnosed a cracked piston. How that can happen I have no idea?

 

They estimate around 7k to replace the piston, but tbh I actually begrudge paying them £132 per hour (around 1k per day) I think that takes the piss lol.

 

So I have 3 choices:

 

1, Let them do it for 7k possibly more.

 

2, Take it away and let a local garage who charge £40 per hour do it (plus Mercs charge so far for stripping it down).

 

3, Sell it as it is. It's in fantastic condition, not a single ding on the bodywork, everything works (apart from the engine haha), FMSH with all invoices. 5k worth of extras including nappa leather and keyless start/go.

 

What d'you think it would fetch on ebay if I sold it as is? I'm thinking that it could be a bargain for someone who could do the work themselves, the parts aren't much- a piston at £300 and a gasket set. What would you do paul? Thanks! :)

 

Hi Trev

 

If you are fed up with it what about a straight swap for mine:lol:

Hi Yew, haha it's been a nightmare sorting this, I've had some good prices from other mercedes garages, I told WSM merc I was pulling the car away and would pay for work to date, but they now want to offer me a lower price tomorrow so we'll see what they come back with. :)

Bad news today - Mercedes WSM have diagnosed a cracked piston. How that can happen I have no idea?

 

They estimate around 7k to replace the piston, but tbh I actually begrudge paying them £132 per hour (around 1k per day) I think that takes the piss lol.

 

So I have 3 choices:

 

1, Let them do it for 7k possibly more.

 

2, Take it away and let a local garage who charge £40 per hour do it (plus Mercs charge so far for stripping it down).

 

3, Sell it as it is. It's in fantastic condition, not a single ding on the bodywork, everything works (apart from the engine haha), FMSH with all invoices. 5k worth of extras including nappa leather and keyless start/go.

 

What d'you think it would fetch on ebay if I sold it as is? I'm thinking that it could be a bargain for someone who could do the work themselves, the parts aren't much- a piston at £300 and a gasket set. What would you do paul? Thanks! :)

 

Been away all week training in Berlin - but if you want to know then I'd give it to me!! :D

 

Tough call - as is there would be limited buyers that would take this on I would think so you would have to be prepared to sell it for silly money.

 

A Mercedes specialist would be a better solution - a far cheaper option.

 

See what they come back with - we have a cheaper rate for older cars as do many other dealers these days, see if they will offer a decent discount first. If they are not too busy they may offer a decent rate especially if you tell them you are prepared to leave it as a "hospital" job where they can fit time in as & when they have free time.

 

On the plus side I have been driving the brand new SL & its a fantastic motor (will post a piccy up on a new thread) - see how much they will offer against a new SL63AMG!! :D

Thanks for reply, we agreed a price of 4k yesterday including vat and 16 new plugs so I'm happy with that. Have chatted to several other Merc mechanics and they've never heard of a problem like this on the 55 AMG engine before either. Apparently the piston is cracked 90% across the top but not all the way to the edges, a mechanic mate thinks it's possible it could have had a flaw from manufacture but others disagree lol. Will have a look for your SL63 thread :)

To be honest I think you have just been really unlucky - it is a very unusual issue for Mercedes on any engines, let alone the AMG's!

 

sounds like a much better price you have negotiated there - I hope all goes well :)

Got the car back yesterday, they've done a very good job as far as I can see and it drives as well as it did before.

 

Have got the old piston too, I'm surprised at how short and stubby it is, and the face looks really thick, but it has a tiny crack right across it - amazing! Paul, do you know the email address of AMG HQ in Affalterbach, I've used this address "marketing-amg@daimler.com" but not sure if it's right? Thanks :)

I've posted some pics of the piston on Pistonheads, it's actually cracked right through the face which is 9mm thick, and through the top of the gudgeon pin holes. Only the underneath of the holes held it together. I'm amazed that a thick lump of a piston like that can crack in half!

 

http://www.pistonheads.com/gassing/topic.asp?h=0&f=96&t=1169920&mid=31636&nmt=Photo%27s+of+my+cracked+piston+SL55+AMG%2C+any+expert+opinions%3F

That is quite surprising! As said - not a common issue at all.

 

Not sure on the email address for AMG - all communication that we do goes through MBUK so we would not contact them directly for anything.

 

Glad you got it sorted - bloody cars, will be the death of all of us!! :D

I've posted some pics of the piston on Pistonheads, it's actually cracked right through the face which is 9mm thick, and through the top of the gudgeon pin holes. Only the underneath of the holes held it together. I'm amazed that a thick lump of a piston like that can crack in half!

 

http://www.pistonheads.com/gassing/topic.asp?h=0&f=96&t=1169920&mid=31636&nmt=Photo%27s+of+my+cracked+piston+SL55+AMG%2C+any+expert+opinions%3F

 

First time I have ever seen a cracked piston Trevz you where very unlucky to get that piston plus I would be worried that the others would have the same weekness.

Glad you sorted it mate.

 

You got some replies on Piston Heads too ;)

Cheers guys, had some news from Mercedes in Maastricht today, they've opened a case file for me so hopefully will get an answer to what they think the cause was. General opinion from every mechanic that's seen the piston is some sort of manufacture/stress fault. Had the car back for 2 weeks now, done 700 miles and all is well.

 

Someone posted this vid on Pistonheads... http://www.topgear.com/uk/videos/mind-my-car from when Clarkson owned it, it still looks the same now but cleaner lol.

 

 

 

 

Nice Top Gear clip Trev and love the sound when Clarkson finally opened it up:thumbup: