Mercedes-Benz SL (R231)

60 sales analyzed · 18 topics from real Bring a Trailer & Cars & Bids comments.

“These MB’s are the greatest bargains in the auto world in my opinion! They are built like bank vaults, very reliable, while expensive the parts are the utmost quality”touchyu2 · Apr 11, 2022 at 7:53 PM

• M278 4.6L twin-turbo V8 character and the 'typewriter' tickmechanical
  The SL550's M278 twin-turbo V8 is rated at 429 hp and 516 lb-ft and is praised for smooth, abundant torque. A recurring point of confusion is a sharp ticking noise on these gasoline-direct-injection engines; knowledgeable commenters explain it as normal high-pressure injector and valvetrain noise rather than a fault. …
• M278 maintenance: Euro-spec synthetic oil and premium fuelownership
  The community consensus is that the M278 is durable if maintained conscientiously, with owners advocating more frequent oil changes than the on-board Assyst Plus reminder calls for, using Euro-spec full synthetic and Top Tier premium fuel. Several attentive owners change oil at 5k intervals despite the 10k factory schedule. …
• Cold-start rattle and the oil check-valve TSBmechanical
  A knowledgeable bidder flagged a technical service bulletin for an oil check valve near the top of the motor intended to prevent cold-start rattling, asking sellers whether it had been performed. Others note a brief clicking on cold startup of the direct-injection engine that clears as it warms. …
• Active Body Control (ABC) suspension: avoid on older carsbuying
  ABC was an option on the R231; the standard car uses Adaptive Damping (code 485) with selectable comfort and sport modes. The overwhelming community advice is that buyers of high-mileage cars should prefer the non-ABC/standard suspension because ABC becomes very expensive when it fails, while the standard setup still rides and handles well. …
• Depreciation and the 'most car for the money' value casemarket
  Original MSRPs of roughly $118k-$125k against auction results in the $20k-$48k range drive a near-universal 'incredible bargain' narrative. Owners frame the R231 as overlooked and undervalued, built like a tank, and offering most of the SLS experience at a fraction of the cost. …
• Dashboard leather delamination and bubblingcosmetic
  The upper dashboard leather is prone to bubbling and pulling away at the seams. Commenters report Mercedes offers an improved/revised dash part (list around $5,940) and quotes running $7,400-$8,600 installed at 10 hours labor; several note Mercedes would not cover it under warranty, though at least one dash bubble was replaced under warranty on a newer car. …
• Magic Sky Control electrochromic glass roofcosmetic
  All R231 SLs came with a glass roof panel; the optional Magic Sky Control uses an electrically switched particle field to go from opaque to transparent. It is prized as one of the best and rarest options by some, while at least one owner considers it a gadget he almost never uses. …
• Retractable hardtop and glass-roof replacement costownership
  The power-retractable hardtop is a signature feature, but replacing damaged roof glass is costly because the glass is built into the frame and not sold as a separate pane; a full top section is much more expensive. Commenters strongly favor factory-correct MB glass over generic aftermarket replacement. …
• Wheels crack or bend on low-profile tiresmechanical
  A well-known issue: the low-profile tires transmit pothole impacts to the wheels, which crack or bend easily. Cracks can appear on the inner rim face; sellers quote new OEM rims near $1,880 each, making repairs and replacements a notable ownership cost. …
• Tire life, run-flats and curb rashownership
  Owners report the low-profile (often run-flat) tires wear quickly, with roughly 13k miles a typical service life, so high-mile cars are on their fifth or sixth set. Curb rash on the wheels is common and repairable, and buyers routinely ask for tire date codes. …
• Auxiliary/secondary battery faults from sittingmechanical
  These cars carry a main battery in the trunk plus an auxiliary battery; an 'Auxiliary Battery Malfunction' alert commonly appears when the car sits unused and often clears with regular driving. The auxiliary battery is inexpensive (roughly $70-$100), though location descriptions vary between behind the passenger seat and under the hood. …
• AMG badging on non-AMG SL550sbuying
  Many SL550s wear AMG badges on the deck lid and AMG wheels from the factory Sport Package, which regularly prompts confusion. Experienced commenters stress these are not AMG cars; a true AMG would be an SL63 or SL65, and the badge/wheels alone do not change that. …
• ECU tuning: Renntech, Brabus and Revtech gainsdriving
  The M278 responds strongly to ECU tuning, with owners citing Renntech adding around 100 hp and 150+ lb-ft while feeling stock in normal driving, and a Revtech handheld tune claiming 500 hp / 650 lb-ft on California 91 octane. Multiple owners call the engine essentially bulletproof with these tunes. …
• SL63 and SL65 AMG variants: power, rarity and valuesmarket
  The AMG models sit above the SL550: the SL63's window sticker shows 577 hp and owners call it 'bonkers,' while the twin-turbo V12 SL65 is rare and valued far higher, with low-mile examples selling from roughly $86k to $140k. AMG owners prize the SL65 motor as something the current SL no longer offers, and note these AMGs rarely appear at low mileage. …
• SL400 / SL450 V6 variants: underrated and reliabledriving
  The six-cylinder SL400 and later SL450 are described by their owners as quick enough, quiet, comfortable, reliable and 'slept on,' with the all-aluminum construction cited as making them the pick of the SL litter. At least one owner claims a mild modification made his SL400 quicker than a friend's SL550. …
• Interior quality, comfort and GT characterdriving
  Owners consistently rate the R231 as an exceptionally comfortable, luxurious grand tourer with one of the best interiors of its era. It is praised as tame when relaxed and ferociously quick when pushed, but described as a cruiser rather than a sharp sports car, less incisive than a 911 while more comfortable and torque-rich. …
• Preventive maintenance items: cam sensor oil, timing cover leaks, console doorsmechanical
  Beyond major systems, owners flag several cheaper preventive items to inspect: oil migrating into the cam sensor/magnet wiring harness (a cheap fix if caught early), timing chain covers that eventually seep because Mercedes used no gaskets, and the armrest storage-console doors that are known to break. Engine mounts are also called out as pricey wear items. …
• Wind deflector / screen separationcosmetic
  The rear wind deflector screen is noted as prone to separating from its frame, and commenters warn there is no cheap fix because the whole assembly must be replaced. Buyers are advised to request clear photos of the deflector's condition. …