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'91 300SL(sold) 2000 SL320 Edition '94 E220 T auto
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Discussion Starter #1
I thought i'd just make a quick post. I'm looking for an estate/wagon and saw my second this afternoon. Last night's 1998 E240 Auto azurite blue one turned out to have a VERY noisy gearbox, so walked away...


....Today's was a very promising sounding one owner 55,000 mile 1998 silver Avantgarde 300TD.

It clap, clap, clapped away momentarily on start-up which made me walk too. However I just did a little reading and it seems like it might just be a glowplug causing this. The glowplug light seemed to remain on, but I walked away moments later....

....I bet it will still sell quickly and I feel 50/50 about pursuing it again just now. It was a bit rusty but otherwise seemed good. It had had a lot of panels replaced under warranty 5/6 years ago. But not the shell!!

Does my diagnosis sound quite good? Are glow's expensive?

I'm am only looking for this car as I am renovating a property and of course the 210 is a cavernous estate! I therefor would have probably preferred a petrol without the diesels pump,turbo and glowplugs. I think the car did have a genuine 55000 miles believe it or not!
 

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1999 E300 TD
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2,045 Posts
W210 MB diesels have a mechanical injection pump and the noise you hear is normally music to the ears of MB diesel owners---very unique sound made by the pressure relief valve opening and closing, that may be louder at start up because the upper part of the pump is lubricated my the diesel fuel. The lower part is connected to the engine oil lubrication system. You just get use to sound

The MB diesels have a pre, during and post compression glow plug system. As you know when you turn the key to the second position the glow plug light comes on and when it goes off you move the key to position three and the car starts.

Are you saying the glow plug light never went out or that the glow plug light came back on when the engine started. There are different reasons for those occurrence one is glow plug the other is the preglow module is faulty and staying on.

What is it?? and good luck they are great cars!!
 

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'91 300SL(sold) 2000 SL320 Edition '94 E220 T auto
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692 Posts
Discussion Starter #3
Many thanks for reply.

I don't actually know if the glowplug light may have momentarily gone off and then came back on again, as the owner of the car started it up. He did sit and wait for a moment or two before cranking the engine perhaps waiting on the glow light going out or maybe he was just waiting even if he knew the light wasn't going to go out afterwards. Perhaps this is 100% normal. On my 4 year old BMW 3.0D you don't have to wait, but I know this merc is somewhat older. Certainly the light was still on after a couple of minutes.

It was a pretty loud clap, clap, clap noise which did just vanish after probably only 10secs, but you can imagine when viewing an unknown car that it was a bit alarming. That is interesting about the pressure relief valve. Having read a bad glow plug can cause diesel knock in a cylinder I did feel it sounded like that. More like that of a diesel tractor engine or something when stone cold, you know, kind of bang, bang, bang into life. But it stopped and then sounded like the refined diesel I expected. It's tough to diagnose noises over the internet!
 

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1999 E300 TD
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2,045 Posts
That's a new one for me---glow plug knock, smoke, uneven start up and hard starting, but never read about MB knocks. The gassers get knocked up all the time!!

There is another Scot in/on this forum who has an odd ball friend in California who purports to have and continuously refers to very old Russian diesel technology. I am surprised he has not chimed in.
 

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E320/E250 Bluetec Ford F350 6.7l
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You know -in Florida you don't need glow plugs at all. :D
As said -those engines do make clapping noise when they run. Maybe what you heard for 10 second was elevated noise from 1 or 2 cylinders misfiring.
The W210 diesel seems to take longer to warm up the plugs than other models. The W124 diesel we have goes off in about 2 seconds, while W210 takes about 6. On cdi engine I started right away.
Being DIY I love to buy cars with small defects. That can make the purchase price very low, while parts are relatively cheap comparing to US labor rates.
If that is single plug that is a problem -this would be $20-30 expense for DIY. Still you want to make sure there are no other problems. The best test for the engine is compression test, but it is difficult on this engine. Other test is acceleration. I remember those cars should make 0-60 mph in about 9 seconds?
 

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'91 300SL(sold) 2000 SL320 Edition '94 E220 T auto
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692 Posts
Discussion Starter #6
Again, thanks for replies, It wasn't any sort of difficult starting or uneven knoks. It was more that I read a faulty or inop glow could cause loud diesel knock on one cylinder.

The car had been running for a couple of minutes with the light still on. I may well have passed up a great low mileage car, but there's nothing I hate more than unexplained engine noises, unless of a sure fire easy fix. As you can imagine although quite cheap the car was still not dirt cheap and had fairly rusty rear arches. As I said above MB did thier duty on it 5/6 yrs ago with major panel replacement under warranty, so most of it looked quite good I suppose. Shame they didn't replace the shell too! They probably should have done!
 
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