300CE Valve Stem Seals

[300CE]

Howdo chaps,

The above are going to need replacing soon as i'm starting to get a bit of smoke on tick-over when the car is warm.

Is this a relatively straight forward job for a competent mechanic to do on the drive* and are there any special tools required?

*It won't be me attempting this as i'm friggin useless at this type of stuff!

Many Thanks in advance.

 

[grober]

Its not a job for the inexperienced! You need a compressor plus a spark plug type adapter and a valve spring compressor tool and a fair degree of patience! Its not a "do it in the drive in an afternoon " type of job imho. http://web.mac.com/dakota/Mercedes/Projects_files/M103ValveSealR&R.pdf

 

[James1976]

Its not a job for the inexperienced! You need a compressor plus a spark plug type adapter and a valve spring compressor tool and a fair degree of patience! Its not a "do it in the drive in an afternoon " type of job imho. http://web.mac.com/dakota/Mercedes/Projects_files/M103ValveSealR&R.pdf

+1 - it's a bit of a pig of a job as you'll have to take the head off - certainly not a "do on the driveway in the afternoon" job - or it may well end up as a "get frustrated and call the garage to pick up the car in bits" job.

Sorry not to be more positive! Easiest way would be to take the head off, or get your garage to do it - then send it away to a head shop - there's an ongoing discussion about cylinder head reconditioning companies somewhere on here I think....

 

[BlackC55]

Are you sure it is not worn rings?

 

[jaymanek]

If its the stem seals you will see a cloud when pulling away after idling and generally you wont see any smoke whilst driving.

It is an "advanced" job and really only one for the full time mechanic. Id opt to have a full head rebuild at the same time, i.e. replace the guides too.

 

[grober]

+1 - it's a bit of a pig of a job as you'll have to take the head off - certainly not a "do on the driveway in the afternoon" job - or it may well end up as a "get frustrated and call the garage to pick up the car in bits" job.

Sorry not to be more positive! Easiest way would be to take the head off, or get your garage to do it - then send it away to a head shop - there's an ongoing discussion about cylinder head reconditioning companies somewhere on here I think....

If you are just doing the valve stem seals and not the guides then you can do it without removing the head. You get the piston on the cylinder in question up to TDC and then pressurise the combustion chamber via the sparkplug adapter and compressed air supply-- this keeps the valves seated when you remove the spring etc to renew the seal. There is a more basic method which supposedly involves stuffing thick cord into the combustion chamber via the plug hole but its time consuming and not so elegant a solution. As other wise heads have said a smoky exhaust can have quite a few causes so best to get a cylinder compression test first to pin down what's wrong.

 

[300CE]

As always, thanks for all the help and effort in responding to this thread chaps it's much appreciated. I'm pretty sure it's the seals as there is a small amount (at the moment!) of smoke if for example i've been sitting in traffic and pull away. There doesn't seem to be anything if i'm straight driving.

I'll let my mate make a decision as to whether he wants to take the job on (it may have to wait until the new year now) - i rarely use the car during the week so he can keep hold of it. Failing that, i'll get a couple of local quotes and start saving the pennies.

Cheers, Justin.