E320 / S212 - Diesel Engine - Tickover Speed

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New Member
Sep 9, 2008
Hi chaps. I'm new around here and posted a couple of threads on the Elecronics Forum last night so tonight I thought I'd pester the Engine forum.
I bought my 2001 E320 CDI Estate last week (94k miles on the clock) and am working my way through the inevitable niggles. Its the first time that I've had anything to do with a diesel engined car so these questions may seem dumb but I'd appreciate some advice :

1. What is the recommended tickover speed/rpms for this model? It seems/sounds a little fast but the rev counter shows tickover to be about 700/800 rpm. As I've said Diesel technology is new to me so maybe that's how they are :confused:

2. If the revs (idle speed) need to be adjusted, where and how on the engine is it done or is it one of those 'has to be done by a highly trained Merc technician etc etc jobs?

3. When first starting up there is a noticeable pong of exhaust fumes (no smoke) outside the car. For example I was sitting in it on my drive with the door open and the engine ticking over. The smell of 'fumes' became quite noticeable and I had to shut the door. No smell in the car though. After its been run and warmed up it seems all is well. I can't detect any leaks in the exhaust pipe which I think is new but I haven't crawled around underneath the beast yet. (However, I have a Merc Garage bill from July to the previous owner showing 'Exhaust pipe (£276.00) so hopefully it all ok).

Any helpful comments will be appreciated. Many thanks
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Perhaps I should have asked 'What is the recommended idle setting for an E320 CDI engine' ? Sorry if its a silly question chaps but I have not been able to find a reference elsewhere.
The idle speed cannot be adjusted.
Thanks, so is the rpm I quoted about right 7/800 rpm at idle and can they be a bit niffy when first started?
the idle is about right - is it smooth and steady not going up and down - thats the usual sign of trouble. And yes they can be a bit wiffy; if you think that is bad try my old w124!
Smiley, many thanks, that's great news. The revs are perfectly smooth and steady. As for the wiffiness I suppose after 40 years of using petrol engined cars I've gotten used their particular 'aromas' and sounds so the diesel experience is all rather new. I must stay I am stunned by the car's performance - its great.

Thanks again

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