Keeping W202 in tip top condition

[KLee]

I have to admit, the last time I was here at the forums the car was giving probs but it has been 1.5 yrs of smooth sailing (touch wood) with the C220. I don't want to push my luck so I've read once about getting the car serviced more frequently when they reach these ages ... what does everyone think.

Can I get some advise if it makes sense to service the car every 6 months instead of annually? What are the specific items/issues I should be directing/mentioning from this knowledgeable forum to the mechanic (my own independent fellow, not MB) to check to ensure continual smooth sailing?

The car has clicked 111K miles. In the last 2 yrs, new radiator, full a/c componentry service, rear diff work, slight engine leak.

 

[Martin]

Same here my 1993 C220 had a new throttle body and radiator 2 years ago, no problems since now on 145K and just returned from a 2000 mile round trip from UK to Italy and back via the Alps. I change the oil and filter once a year, changed all the top and bottom hoses, drive belt, etc before any failures occured. Not sure whether to keep it or replace with my brothers 2000 C200K W203 on 80K..........more complex, less well built? What does anyone think?

 

[KLee]

Hmmm, I don't know what to think, just after posting, just the one time, I heard a high pitch cranking sound from the engine whilst inside the car and turning the key full right to start the engine. I may have kept it at full right maybe a split second longer than usual. I don't want to try reproducing it again before I'd check with you guys - if one kept the key full right AFTER the engine starts, does this produce such a loud alarming sound?? Sounded like metal hitting a high velocity spinning gears or something - come to think of it I remember hearing the same as a kid when relatives had the huge E classes during the 80s - they all had this same squelch when starting! What is it?

 

[Rob77]

Sounds like you're just trying to make the starter motor start an already running motor. That would make it squeal

 

[KLee]

Thanks Rob, I'm gonna try reproducing just for peace of mind. Btw, I've installed in a huge full length battery in the boot (prev battery was only taking up half the space and when it died ... I went for the big one!).

I have a question that may or may not be related to battery: when starting and then the 15 seconds immediately after when it is idling, IF the a/c is ON 40% of the time the engine struggles to keep up, it shudders, it revs high to keep alive then slowly calms down. But IF after I set ignition to ON only, then toggle the a/c OFF and only then start the engine, all is nice and well, smopth idle, beautiful calm.

The a/c is placing extra demands at engine start - what is this telling you? Advise what to look into please.

 

[NW_Merc]

I'd say alternator or spark plugs

 

[grober]

In terms of long term maintenance what folks tend to overlook are regular brake fluid changes ( water absorbtion) particularly in a high humidity environment and engine coolant renewal ( depletion of anti corrosion additives) . Since you had the coolant renewed recently with your radiator work should be OK for now. Some folks also advocate changing the power steering fluid and filter too. Frequency of servicing is not so important as regularity IMHO. Its missing out service items that does the damage. If you stick to the manufacturers recommendations you should be fine. HOWEVER Don't ignore manufacturer recommendations that advocate more frequent engine oil and filter changes if the car is used on short journeys or very hot dusty environments for example where you would want to change the air filter more often. likewise the fuel filter if your petrol was likely to be dirty. You raelly have to judge these things for yourself depending on the environment and way the car is used. You should also keep an eye on disc brake wear and check the condition of your flexible brake lines if you wish to maintain -- ex-production braking performance. You understand the brakes will still be OK but not as good as new performance. There is also the chance you have one of the generation of cars with the "biodegradeable" wiring which tends to go brittle with age --particularly in the engine compartment due to heat. signs of this is flaking plastic insulation and mysterious electrical problems. My advice would be to minimise handling the wiring loom as much as possible and exercise care when servicing the car. lots of posts on this on the forum.

 

[KLee]

Grober thanks for your invaluable input. I will ensure to list all the items mentioned in the next service. The car is used mainly on weekends - short 10km round trips on Sat in traffic and on Sun a long trip on motorway at 110km/h 1 hour roundtrip. Yep definitely disc brakes - I remember the mech saying the front ones - could be on its last leg.

Touch wood mine doesnt have the bio cables - it all looks good in the engine bay. TOuch wood again I didn't need to replace the throttle body (gulp) - it was a suspect at one time until it turned out to be the MAS, phew (which btw was the sweetest DIY swap with the biggest result you know what I mean).

The thing with the a/c is bothering me cos to work around the engine shuddering is to always :
- start with the a/c off
- having moved off turn it on whilst the accelerator is depressed
- not too sure about this one - having moved off, if I were to stop at a light, only turn it on if in Neutral, if I did it in Drive, most likely will shudder

Maan, its so temperamental. What is the culprit based on these clues/symptoms?

 

[grober]

There should be signals going to the engine to let the engine idle control know that theres an extra load on the engine with the aircon on to compensate. I have a vague memory about a clutch on the air conditioning compressor which should disengage if the load is too great on the engine---maybe thats at fault or the compressor is getting harder to turn in its old age?

there are 2 alternatives really either
(a) the aircon compressor/clutch/controls are faulty increasing the load on the engine to where it cant compensate.
OR
(b) the engine idle control is not getting the right signals to compensate for the increased load of the aircon compressor

I would tend to explore (a) first

 

[Dieselman]

ARe you sure the shudder isn't just the aircon compressor clutch kicking in so gives a shudder. It can feel like a misfire but isn't.

 

[mchips]

Your air-co issue sounds normal. The compressor doesn't usually kick in until a few seconds after the start even when in the on position and I think this is by design to make it less complicated for the engine to start. Once the AC kicks in, there is a relay or something that tells the engine to speed up to compensate for the extra load from the compressor.

 

[KLee]

The shudder when it happens can't be ignored, to the point the engine is almost cutting out and then it revs high to keep alive. THat kindav shudder. mchips I think I know the situation you are alerting to - I have noticed this too - a second or two after ignition the rev meter dips a little and then an increase in the revs. Then in this situation all seems ok - although I'd prefer not to be having the dip in revs if I had a choice. ANyway as you said this is normal op (none of the jap cars do this though ). THe shudder when it happens though is not normal - I suppose it starts off normal but that dip really dips! to the point of cutting out.