Percival504

I am aware that there are a number of other similar threads on the question(s) I am about to pose, but either the questions have been unclear or not entirely the same as my own, or the responses have quickly degenerated into questions concerning performance and handling rather than the more basic questions I have.

I have a 1990 500SL which was in somewhat poor condition when I purchased it. Its condition has only gotten worse as I have neglected repairs (not for lack of resources, but because I was unpersuaded that a complete restoration of a 1990 500SL with more than 100K miles would be economically practicable).

I do understand that these cars are quite reliable. But it also appears that there are common problems which necessitate costly repairs. I am not adverse to the costs of maintaining an R129, but I would be disinclined to spend $5,000.00 to repair what would be a $15k to $20k SL600. I have found a 1998 SL600 SL1 (sport package) which appears to be in very good condition and am strongly considering buying. I wonder, though, whether the reliability of the SL600 is less than that of the SL500. If possible, I would also like to determine what average annual maintenance costs are for SL500s and 600s. Finally, I would guess that the cost of maintaining the SL600 exceeds the cost of maintaining the SL500 by a fair margin, but I wonder whether the margin is 15% or 30%.

Any advice would be greatly appreciated. TIA.

HLG600

The M120 V12 is essentially grenade proof. Issues/maintenance costs I've encountered include:

1. Starter Module Failure - $700 + $150 for flatbed tow.
2. Clogged Primary Cats - $1500
3. Fouled 02 Sensors - $360 (4 Sensors)
4. ESP Module Glitches - $400 in diagnostics. Thankfully it cleared up, because a new module would have been $3000.
5. New Plugs - $400
6. Hydraulic Soft Top Leak - Traded the car in at this point.

Overall, a very enjoyable and relatively fast car. But alas, as with any out-of-warranty German car, costs can become quite high. Your best bet would be to find a clean, well-kept example, and put aside $5K cash for repairs. Prices above reflect parts + labor, through an independent mechanic. Feel free to message me if you have any specific questions.

Cheers!

Percival504

The seller just advised me that he is replaces on of the rear shocks (due to a leak). Am I wrong in suspecting that the failure of shock may be a harbinger of the failure of the remaining 3?

HLG600

The ADS system is the primary crux of the 600 model, as it is costly to repair and more prone to failure than a standard suspension setup. ADS usually is fine up to 100K miles...but it is always safer to assume the worst with such a car.

Jimmy Chen Shib

I think you are choosing the correct decision to move to SL600, instead of the SL500 as said. Based on my own experiences, MB models span around ten years before model changes. Early models tend to have problems, which get resolved over time. Thus, acquiring late model (as in your case) is the prudent and wise choice. Based on my own experiences, I have owned mine since 1999 and glad to say that I am happy with the car. The last expense few months ago involved the two rear suspensions. Now, the car runs beautiful again. Do let us know of your decisions. Good luck. w/ smiles Jimmy

Percival504

NM