Cam belt or chain????....that is the question..

[Bart]

Hi again,

I was just wondering if the c240 had a chain or belt.....i think its a chain but i'm not sure.......and when is it expected to be changed within the engine service life time.....

TIA

 

[recycled]

chain.
if you go to the dealers they will tell you that change is not recommended.
At least that is what they told me.

 

[Dieselman]

chain.
if you go to the dealers they will tell you that change is not recommended.

Until it goes bang..

I'd be loath to let on go past 180K on a petrol.

 

[recycled]

i shall say 150k for a petrol. do not know about diesel though

 

[grober]

3 changes to 1 ratio at least!

If its a duplex chain http://www.detali.ru/cat/oem_mb2.as...GM=717.464&CT=M&cat=19X&SID=05&SGR=015&SGN=01
and its looked after- ( no over-revving) with regular oil changes and the tensioners are OK then --the effective life of the engine. By the time its getting worn so will the associated valve gear, piston rings, oil pump etc etc. Thats not to say the engine wont be good for many more miles but will be exhibiting some signs of wear and tear. Cambelts on the other hand will require changing on fairly regular basis to avoid expensive engine blow ups. Like many fabric/composite materials they degrade more with elevated temperatures. This can alter their design life quite markedly so its difficult to predict exactly when they should be changed mileage/age -wise. Most manufacturers err on the safe side when they specify when they should be changed but under harsh conditions ( heat, chemical stress,UV,dust)they should probably be changed at shorter intervals.
They have been adopted by manufacturers because they are cheap ( think glorified poly-V belt) don't require lubrication and are quiet. Changing them as required by a service schedule can add considerably to the routine servicing costs because of access problems. Just ask any Ferrari owner.

 

[Dieselman]

They have been adopted by manufacturers because they are cheap ( think glorified poly-V belt) don't require lubrication and are quiet.

And maintain accurate timing throughout their life, whereas chains wear so allow the timing to retard.

 

[recycled]

best to find out if anyone here has changed thiers and at what mileage and if anyone has had a failure yet. i havent but i have just crossed the 105k miles

 

[Doodle]

Generally you get plenty of warning when the chain is on its way out...a luxury the belt does not afford.

However, if you ignore those warning signs (as I know one Accord owner did), it still does the same amount of damage.

 

[milker1mbc]

I had a chain go on me when I was doing 70+mph on the M25, rev counter just started dropping and lost all power, just managed to get over to the hard shoulder and wait for the RAC. There was no big bang and bits flying everywhere, it just expired.

When the RAC guy started pulling a chain (I think it was a duplex) up through the oil filler cap I remember thinking "I'm fairly sure he shouldn't be able to to do that!"

There was actually only minor damage to the valves and pistons but enough for me to call Crewe Engines for a replacement.

£1500 (at the time) and a week later I had a nice refurbed engine that went better than the original did (before it died). That was a 230TE and it had done about 140k miles.

The next 230TE I had, I had the chain changed before it had done that many miles.

 

[recycled]

I had a chain go on me when I was doing 70+mph on the M25, rev counter just started dropping and lost all power, just managed to get over to the hard shoulder and wait for the RAC. There was no big bang and bits flying everywhere, it just expired.

When the RAC guy started pulling a chain (I think it was a duplex) up through the oil filler cap I remember thinking "I'm fairly sure he shouldn't be able to to do that!"

There was actually only minor damage to the valves and pistons but enough for me to call Crewe Engines for a replacement.

£1500 (at the time) and a week later I had a nice refurbed engine that went better than the original did (before it died). That was a 230TE and it had done about 140k miles.

The next 230TE I had, I had the chain changed before it had done that many miles.

Good. Where did you get that done?

 

[Dieselman]

Good. Where did you get that done?

Doing it is actually pretty easy apart from peening over the new chain pins. Dealers have a special link extractor that can press the pins just so.
A couple of hammers is supposed to work but is more risky.

Once the old chain is parted the new chain can be attached and wound in as long as the chain is kept tight onto teh camshaft and the free end pulled out and kept tight.

Brave souls use the starter motor to wind the engine over..

 

[Dieselman]

Double post..

 

[MBManInKen]

I had a chain go on me when I was doing 70+mph on the M25, rev counter just started dropping and lost all power, just managed to get over to the hard shoulder and wait for the RAC. There was no big bang and bits flying everywhere, it just expired.

A broken chain was what made my V140 S500 expire on me last Autumn. It happened just after setting off, no bangs or anything, but engine cut off almost straight away and all lights came on. Whole engine locked up almost instantly.

Had it towed away. Diagnosis: chain broken, cam broken, cylinders crashing into valves, damaging both. Verdict: new engine needed, cost about 20K .

Got a second opinion somewhere else, essentially same verdict. Wrote the car off as a result.

It had 99K miles on the counter. No indication whatsoever that the bloody chain was going to go. Had been in for maintenance 2 months earlier - no mention by the dealer that anything would be wrong either.

Car always well maintained regardless of costs, never driven like a lunatic either.

Spoke to DCUK - some bloke told me that it happened more often than I would think. Wasn't willing to put that on the record though!!

Almost put me off buying Merc again

 

[Dieselman]

Was it definately the chain that broke. V8 MB engines have a nasty habit of the chain tensioner guides going south which then releases the chain.

 

[MBManInKen]

Was it definately the chain that broke. V8 MB engines have a nasty habit of the chain tensioner guides going south which then releases the chain.

Well, I did some asking round at the time and someone else suggested exactly the same thing. So, I asked the dealer that did the diagnosis and he basically said that a lot of the inside had been damaged and he could not be sure about the exact sequence of events but that the chain definitely was broken.


Do you know if there are any tell tale signs that the tensioner guides are on their way out? Wouldn't you hear it? Is there anything that can be done to prevent this from happening?

 

[recycled]

Ian walker said earlier his went at 115k others have said bout 180k. i think its pretty much guess work here. Nothng definite. maybe the bigger the engine the earlier the change.

 

[MBManInKen]

i think its pretty much guess work here. Nothng definite. maybe the bigger the engine the earlier the change.

Cheers - I wish I could get a proper answer from MB on this. When I spoke to them at the time, first they didn't even want to recommend anything. When I asked if they consider it normal that the engine on one of their top end saloon went **** up, they said they could not comment. When asked if the chain needed replacement at some point they said yes, suggested about 150K but could not answer my question why (a) there was not a word about it in the maintenance schedule and (b) why mine had gone at less than 100K.

And then they wonder why people look at other brands!

 

[recycled]

Cheers - I wish I could get a proper answer from MB on this. When I spoke to them at the time, first they didn't even want to recommend anything. When I asked if they consider it normal that the engine on one of their top end saloon went **** up, they said they could not comment. When asked if the chain needed replacement at some point they said yes, suggested about 150K but could not answer my question why (a) there was not a word about it in the maintenance schedule and (b) why mine had gone at less than 100K.

And then they wonder why people look at other brands!

You are dead right. i went to mine to look at a cl500 i saw on the website
(road range liverpool) while i was there i asked the service department about the c180 chain. They said "we do not recommend changing it at all"
I said chains do not last forever you know. All i got was no comment. Its like they want it to fail so they can charge you loads for a replacement.
I have emailed crewe emgines though to see what they recommend andif they do as well. Shall keep you posted

 

[MBManInKen]

I have emailed crewe emgines though to see what they recommend andif they do as well. Shall keep you posted

Cheers - I got a quote from them for a reconditioned engine which was reasonable (can't remember the exact amount), but the amount of work to do the swap was a killer in terms of costs - couldn't really justify spending that much on a '96 s-class, so (reluctantly) wrote it off and started looking for a new car

 

[MBManInKen]

They said "we do not recommend changing it at all"

At the time (and now still actually) I was appalled that MB did not seem to have a proper strategy wrt the chains and the guides.

Surely, the proper thing would be to have a specific point in the maintenance schedule for replacement of guides and chains well on time to avert disaster, especially if their failure is catastrophic for these interference engines...