2018 — 2023
3.0L I6 Turbo + EQ Boost (CLS 450) - AWD
Hybrid/Petrol
Observe the gear shifts while cruising in Comfort mode. | Note: While smooth in most cases, the 9G-TRONIC transmission can sometimes exhibit minor hesitation in this specific chassis; ensure gear transitions feel seamless rather than jerky during your test.
Test the MBUX infotainment system thoroughly. | Note: Check that the screen responds promptly to voice commands and touch inputs, as software glitches can occasionally arise in early C257 models.
Turn the wheel to full lock in both directions while at a slow crawl. | Note: Listen carefully for any clicks or groans from the suspension; it is worth noting that the multi-link setup is sophisticated and may require attention if previous owners drove over harsh road surfaces frequently.
Check the EQ Boost transition during stop-start traffic. | Note: Pay attention to how the car restarts at traffic lights; the 48V mild-hybrid system should provide a near-instantaneous transition. If it feels sluggish, it may be worth getting a diagnostic scan.
Time to consider a transmission fluid and filter service to keep the 9G-TRONIC shifting smoothly.
A prudent time to inspect the auxiliary battery system and the cooling system components.
Consider having the spark plugs and ignition coils checked for optimal EQ Boost integration performance.
Stick to the Mercedes-Benz specified service intervals to ensure the sophisticated inline-six engine remains in peak condition.
Keep an eye on the tyre tread depth, as the CLS is known to be quite demanding on high-performance tyres.
Ensure the panoramic roof drains are kept clear during your regular cleaning to prevent water ingress.
Verify that the battery health is checked annually, given the reliance on the 48V EQ Boost architecture.
Use only MB-approved engine oils, as the turbocharger cooling system is sensitive to oil specifications.
Estimated repair costs if issues arise
If your chosen model is equipped with air suspension, it is common to consider that air struts can eventually wear over time. If a strut requires replacement in the future, it is a significant job, so keeping a small buffer is wise.
The mild-hybrid battery is a complex component. While usually reliable, you might eventually need to budget for its replacement if it loses its charge capacity as the vehicle ages.
In cars of this age, cooling system seals can begin to show their age. If you notice any low coolant warnings, it is common to look at replacing these components to maintain engine health.
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Disclaimer: This report is generated with the assistance of AI analysis based on verified automotive data. While we strive for 100% accuracy, enthusiasts should always conduct physical inspections and consult service records. View Full Disclaimer