Mercedes-Benz C-Class C43 AMG Engine Replacement Compare Prices & Get Quotes

A replacement M276 engine for a C43 AMG typically costs between £1,200 and £6,500 depending on condition. Used units start from £1,200-£2,500, reconditioned from £2,800-£4,500, and fully rebuilt from £3,200-£6,500. Labour for supply & fit adds £800-£1,500 for AMG-specialist work.

• Used M276.823: £1,200-£2,500
• Reconditioned M276.823: £2,800-£4,500
• Rebuilt M276.823: £3,200-£6,500

The C43 AMG uses the M276 engine, which has a timing chain, not a belt. However, the M276 is known for camshaft adjuster rattle and timing chain tensioner wear - a rattling noise on cold start (2-3 seconds) is the classic warning sign. Mercedes has a service bulletin (LI05.10-P-056435) on this for M276/M278 engines.

• M276: timing chain - tensioner and camshaft adjuster wear are known issues
• Cold-start rattle (2-3 seconds) is the warning sign
• Regular oil changes are critical for chain longevity

Common signs of engine problems in the C43 AMG include: a rattling noise on cold start (camshaft adjuster or timing chain tensioner), reduced power or intermittent limp mode (turbo/wastegate issues), a rattle from the turbocharger area (wastegate linkage wear), rough idle (PCV/oil separator issues), and grey smoke under hard acceleration. If you experience any of these, have the car inspected immediately.

• Rattling on cold start - camshaft adjuster/tensioner
• Reduced power - turbo/wastegate issues
• Rough idle - PCV/oil separator issues

It depends on the car's condition and mileage. A W205 C43 AMG is typically worth £12,000-£30,000 - a rebuilt M276 engine (£3,200-£6,500) is usually well within the car's value and can be a worthwhile investment if the car is in good condition. For lower-value examples or those with multiple issues, a specialist repair (camshaft adjuster, wastegate, PCV) may be more economical than a full replacement. The C43 AMG's strong retained values mean replacement is usually justified for well-maintained cars.

• Vehicle worth £12,000-£18,000: rebuilt engine viable for good condition cars
• Vehicle worth £18,000+: rebuilt engine usually justifies cost
• Preventative repairs: often more economical than full replacement

The M276 is a 3.0-litre V6 biturbo engine used in the C43 AMG, producing 367-390 hp. The M177 is a 4.0-litre V8 biturbo engine used in the C63 AMG, producing 476-510 hp. The M276 features a 60° V-angle and compact twin-turbo layout, while the M177 is a 90° V8 with "hot-vee" turbo placement. Both are hand-built under AMG's "One Man, One Engine" philosophy, but the M177 offers significantly more power and a distinct V8 character.

• M276 (C43): 3.0L V6 biturbo, 367-390 hp, 60° V-angle
• M177 (C63): 4.0L V8 biturbo, 476-510 hp, 90° V-angle, "hot-vee"

Power loss in the C43 AMG is most commonly caused by turbocharger and wastegate issues. The M276 biturbo can suffer from wastegate rattle, linkage wear and underboost complaints. A low-boost code does not automatically mean the turbocharger has failed - a vacuum leak, weak vacuum supply, leaking pneumatic actuator, sticking wastegate, worn linkage, faulty pressure transducer, boost leak or sensor issue can all produce a similar complaint. Other causes include camshaft adjuster failure affecting valve timing and HPFP issues affecting fuel delivery. A diagnostic check with Mercedes STAR/XENTRY or compatible equipment is essential to identify the exact cause.

• Turbo/wastegate issues - most common cause of power loss
• Camshaft adjuster failure - timing drift and power loss
• HPFP issues - fuel delivery problems under load