I have a 2000 CLK 430 convertible purchased new 6 months ago. I drive about 7500 miles/year. The "Flexible Service System" says I'll go 10,000 miles before an oil change. This hasn't changed over the last 6 months and 3500 miles. Is it safe to go more than a year between oil changes? Does the FSS actually monitor oil quality or just tell everybody to change at 10K? Also, will my included free scheduled maintenance cover an oil change prior to the FSS indicating it?

John,

The FSS interval starts out at 10,000 and will adjust according to all the variables it monitors. In your case it will come on at the one year mark after you got the car.

Your dealer will change oil and filter at no cost during the warranty period at the FSS interval. There was a post by a pro tech a few weeks ago that indicated they had seen some sludge in some engines that had oil changes at FSS intervals. He said he was not supposed to talk about it, but it was easy to read between the lines.

John, oil is the cheapest insurance you can dream of for long engine life. I am using Mobil One in my new M112 motor and changing it between dealer recommended intervals.

If you pay for it, they will change it for you between FSS intervals. If you still want to go the full distance, I recommend using Mobil One to give the engine a fighting chance. I use Mobil One in my new engine anyway, and still change it at about 5,000 miles.

Also, if you only drive 7,500 miles a year, you should change it on a time basis not mileage. The FSS will let you go one year before telling you to change it regardless of mileage. Don't go one year, change it every six months.

If you were to change oil every six months with Mobil One, it would be about $30 worth of oil and a $7 filter. Is your car worth spending less than fifty bucks every six months? With such low annual mileage, changing your oil every six months and using Mobil One, I would be willing to make a very serious wager that you will get rid of the car because you're tired of it, or you decide to give it to your great grandson, before the engine would die.

Best of luck, and enjoy,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

I am not a big fan of synthetic oil or very frequent oil changes but for a car in that price range one could certainly make a case for synthetics. It would probably even help the resale a little.

As Larry said, there are other factors involved with the deterioration of your engine oil besides mileage. All engine oils contain detergents and additives. These additives allow the oil to withstand fluctuations in temperature and also to suspend the byproducts of internal combustion. These aditives will wear out more quickly if they are exposed to extreme operating conditions (such as towing a trailer across country) etc. They will also simply wear out over time. As Larry said, if you are using Mobil 1, given your stated use, you should change it every 6 months at least. It is cheap insurance. If you are using regular oil change it every 3 months. There is something else to consider. That is your driving style. 7,500 miles a year works out to about 37.5 miles per day if you only drive your car on week days. Assuming you take one or two long trips a year this leads me to believe that most of your driving is short trips (15 miles or so). Short trips do not allow your engine oil to heat up fully. Even if your engine temp indicator has reached its operating level by the end of your trip your oil may not have heated enough. This is significant for several reasons. As I mentioned before, when you drive there are byproducts of the internal combustion process. Most of these contaminents are very acidic. These contaminents are suspended in your engine oil and will burn off if the oil gets hot enough. If your oil does not get hot enough they will remain suspended in your your engine oil and can do damage over the long term. Condenstaion can be another problem. When the weather gets colder your engine starts off cold and heats as you drive. This causes condensation. This is not a problem if you drive long enough to burn the condensation off. If your engine doesn't get hot enough it will not burn off the condensation and that will remain in the oil. This can also cause problems over the long term. Condensation can leave a white film over some of the hoses that oil passes through when the engine is running. When the engine stops this forms into a goo, and it can seriously prevent proper oil flow. It happened to me once so bad that when I started the car I was getting no oil pressure. The Breather hoses had been full ove condensation which had frozen over night on a trip to Quebec. The oil couldn't pass through the breather hoses and was blowing right out of the dipstick. Fortunately I always try to keep an eye on the guages and shut the car off immediately when I noticed no pressure. I lost about 4 quarts through the dip stick. I had to remove the breather hoses and clean them thouroughly as well as the valve covers. They were full of white gunk. Fortunately no damage was done. Needless to say I now change my oil every two months or 2000 miles, which ever comes first. At alittle over a buck a quart for Castrol GTX it is indeed cheap insurance. Change your oil more than once a year. If you follow the FFS and change every 10,000, at the rate you drive than is one oil change every 1 year and 4 months. That really should be almost three changes if you use Mobil 1 and at least 5 if you use regular oil.



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Jason Priest
1986 420SEL

For a car that's leased and will be returned before the warranty expires, I would go by the FSS intervals. Otherwise, "change it hot and change it often". It's a small invsetment that is likely to prolong your engine's life and increase resale value.
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AK
87 260E
75 FIAT 124 Spider

Well Like Larry says, Oil is cheap. there is really no harm in spending the $30 or less and change it more often. What if you decide to buy it after the lease? Any damage done will then be with you.

If I had a new car, I'd change the oil every 2-3k...

In my car now, just got it about 6 weeks ago, I have already changed the oil once, and will do it again after 3k miles. and again and again and again.

I'll be changing it hot, and often as larry puts it, and with a filter each time. So all in all my oil changes will cost me about $20 every 2-3 months. Thats not a bad cost. Roughly $80 to $120 a year to protect your engine.

Oil is the only way you can clean your internal parts of your engine as Larry puts it. I find this to be good advise for anyone. Oil is Cheap.

Alon

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'92 300CE
Metallic Black (Blue Flaked) on Parchment
Clear Corners
94-95 Tail-Lights
Black Grille Insert
78.5k Miles

Future Upgrades:
Sportline Suspension
17" AMG Monoblocks or EVO II's
Euro Headlights
Performance Chip
AMG Exhaust

Click here to Go To My 300CE Page

[This message has been edited by Ashman (edited 11-01-2000).]

well...if i were to throw my 2 cents into the pot I would have to agree with Ashman.
There's been ALOT of discussion about synthetic vs. non-synthetic oil. From what iI have been told and from what I have read in other sources, the quality of the oil is not as important as the frequency and the regularity of the oil changes. If you change your oil religiously every 3000 km, you don't need to pay the extra for synthetic oil.

If you're onre of those people that leaves the oil change for about 5,000km or more, then you may want to consider it. Although I don't know what good it will do at THAT interval *L*

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Cheers!

Yen-Hsen Liem
'93 500E black pearl/black leather; 89,000km; 245/45-ZR17 Michelin Pilot SX; 17x8.25 factory EvoII
'93 500E bornit(blackberry)/black leather; 69,000km; european delivery; 245/45-ZR17 Michelin Pilot SX; 17x8.25 factory EvoII
'88 560SL desert taupe/dark brown leather; 89,000km; Euro headlights
'87 190E 2.3-16 black pearl/black leather; 55,000mi; Euro headlights
'70 280SL white/red; 135,000mi (original); factory alloys; Euro headlights

I'd change regular every 5,000 miles and synthetic at 7,500 miles. Anything less than that is too early IMHO. Synthetic could go up to 10,000 miles if you only do highway driving.

Either way, I'd stick with Mobil 1 15W-50 Synthetic for summer and Mobil 1 10W-30 Synthetic for winter (up north).

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1988 Mercedes-Benz 260E (W124)
Arctic White/Grey
Debadged
Euro Headlights
Clear Turn Signals and 1994/1995 Taillights
16" x 7J 8-hole
Michelin Pilot HX MXM 205/55WR16

1997 Mercedes-Benz E420 (W210)
Pearl Black/Ash
Debadged
Michelin Pilot XGT Z4 P225/55ZR16

1997 Mercedes-Benz C280 (W202)
Polar White/Parchment
Michelin Pilot SX-GT 205/60VR15

[This message has been edited by DSinger (edited 11-02-2000).]

I do lot's of highway driving. Most of my trips are 90 miles. This gives thorough engine warmup and very few cold starts per oil change. Warmup is where most damage occurs anyway.

But, this said, I still can't buy in on 10,000 mile oil changes. I don't care what kind of oil, what kind of service, what kind of oil filter, or what kind of engine. If you have leased a car for a few years, of course, change it every 10K, or even less frequent if the factory recommendation allows it. If you buy a car to drive for many years, you need to wear out the oil drain plug threads before anything else.

I will restate my unscientific study here; 3,000 mile interval, oil drain hot and overnight, oil filter every time, got 380,000 miles from engine.

My $0.02,
Change oil hot and change oil often,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles