Noisy S320 CDI

[kheath74]

As part of my list of issues with my W220 CDI 2003 I have already posted on the glow plugs light being lit constantly, I have noticed the noise from the engine now when I accelerate is quite high, it is a deep noise and not as smooth as I thought a S Class should sound.

I know its a diesel and the noise they make having moved from 2.5 Turbo Diesel Nissan Navara, but this is a bit too loud I feel for the S class cabin. With the glow plugs looking like they are shot, would this explain the noisy engine, I am thinking that I may take the car in for a mechanic to look over and let me know their opinion. The ASSYST states I dont need a A Service for 12k but I am beginning to think I should have it looked over now just to be sure.

 

[BlackC55]

Couls this be engine mount wear?

 

[kheath74]

Is there a way I can check this or do I need a engineer for this? I do notice the noise reduces once its been driven for 15 minutes or so, but on a cold start its pretty noisy.

 

[Xtractorfan]

When starting from cold they can be noisy, if the glow plug light is still on after starting then your glow plug relay may have blown one or two of the fuse links..could need glow plugs replacing as well...The glow plugs do help to warm up a cold engine, I have found that using low sulphur city diesel..supermarket fuel makes my car noisier,
There is a thread on here about using 2stroke oil in the diesel, it may be worth a try.. ..
And I agree an S class should be seen and not heard..

 

[kheath74]

Thanks Xtractorfan, I drove into work this morning, a 40 mile motorway drive from Stoke and by the time I arrived in Birmingham the engine was running much smoother and quieter, a move from 20-50 was a quiet surge as you would expect from an S320 as opposed to a chugging noise when I left home. This all seems to suggest a cold engine is noisy and once warmed up the engine performs as it should, this coupled with the constant glow plug light makes me think the plugs need changing!

Right now I have to search out a good local garage in the West Midlands!

 

[brandwooddixon]

It's been a while since I owned a diesel vehicle - my last was a 1971 LWB Land Rover.

The glow plugs were dead when I bought it and until the compression cycle had sufficiently warmed up it would chug along a lot more than normal. There was also lots of unburned diesel exiting the exhaust pipe as well.

You will probably find that once the glow plugs arw working properly the engine will run smoother sooner, as you will be burning the diesel more efficiently.

 

[rpe2]

My 320CDI sounds like a tractor in the cabin at the mo. Coupled with my feet being colder than usual led me to a split boot where the steering column goes through the floor.

On this subject, where do I have to disconnect the steering linkage, is on the engine or cabin side of the bulkhead?

Thanks

 

[jberks]

It's been a while since I owned a diesel vehicle - my last was a 1971 LWB Land Rover.

The glow plugs were dead when I bought it and until the compression cycle had sufficiently warmed up it would chug along a lot more than normal. There was also lots of unburned diesel exiting the exhaust pipe as well.

You will probably find that once the glow plugs arw working properly the engine will run smoother sooner, as you will be burning the diesel more efficiently.

Modern cdis don't really need the glowplugs and will start and run fairly happily without them, unless its really cold that is. But, until they warm up they do sound like an old massey fergusson. Warm up takes maybe 1-2mins but if the engine pre-heater isn't working it will take a lot longer as teh cdis don't kick out enough heat on their own.
So, on this S Class, is the pre-heater working ok?

 

[kheath74]

I suspect the pre heater isnt working as the glow plug light in on the dash constantly and I suspect the engine only gets warm after an hour of motorway driving at 6am, once I get to work there is little noise and acceleration is smooth again. At 6am I have a tractor engine!

I am looking for a good garage to go to, although I did my best on purchase there are always issues you notice later and no doubt the dealer ran the car for a while before I tested it both times, so I think I will let a engineer look it over and make their recommendations and I will look at what I can afford to have done then.

 

[jberks]

I suspect the pre heater isnt working as the glow plug light in on the dash constantly and I suspect the engine only gets warm after an hour of motorway driving at 6am, once I get to work there is little noise and acceleration is smooth again. At 6am I have a tractor engine!

I don't think the pre-heater is monitored by anything so the coil light will be a different issue. Neither too serious though. From your description I'd agree that it strongly sounds like your pre heater isn't working. My 270 is warm enough to hear yourself think within a minute and quiet and smooth within 5. My the time I hit the motorway (10 mins) shes done all the warming up she's going to do. So if you're an hour in and not up to temp, it needs attention, especially as the lubrication won't be working properly at lower temps - not good with motorway use.

 

[kheath74]

I am sure now of an intermittent fault, I drove home again from work and started up with engine temp guage at 40C, noisy start and noise when accelerating, then after 10 mins I am up to 70C and it stays there for 40 mins. However I got near home and the plugs light goes off and the engine becomes smooth again, I got home let the car rest for 10 mins and started again, plug lights and goes out. Engine smooth and little noise, engine temp at 85C.

I went the gym for an hour and on start, plug light on then off, engine temp straight up to 85C and smooth pull and little noise.

So I am relived at least that the engine runs great when the plug lights heats up right, so Im hoping it keeps working until I can get to a garage for a service.