Mercedes-Benz AMG GT R Engine Replacement Compare Prices & Get Quotes

A replacement M178 LS2 engine for a GT R typically costs between £5,500 and £19,000 depending on condition. Used units start from £5,500-£9,000, reconditioned from £11,000-£15,000, and fully rebuilt from £11,000-£19,000. Labour for supply & fit adds £800-£1,500 for AMG-specialist work. A typical GT R is worth £100,000-£195,000 , making engine replacement a viable investment for well-maintained cars.

• Used M178 LS2: £5,500-£9,000
• Reconditioned M178 LS2: £11,000-£15,000
• Rebuilt M178 LS2: £11,000-£19,000

The GT R uses the M178 LS2 engine, which has a timing chain, not a belt. However, the M178 is known for timing chain stretch - a rattling noise on cold start is the classic warning sign. An NHTSA Technical Service Bulletin (LI05.10-P-049909) identifies timing chain stretch as a known issue, noting that vehicles with less than 50,000 kilometres require individual assessment .

• M178 LS2: timing chain - durable but stretch is a known issue
• Chain stretch common at 50k-80k miles
• Regular oil changes are critical for chain longevity

Common signs of engine problems in the GT R include: a rattling noise on cold start (timing chain stretch) , loss of power or limp mode (turbo actuator failure) , white steam from the engine bay or low coolant warnings (crossover pipe leak), and blue smoke on startup or after overrun (valve stem seal failure). Owners also report stuck injectors, oil leaks from the transmission case, and faulty exhaust flaps as known issues .

• Rattling on cold start - timing chain stretch
• Loss of power - turbo actuator or boost leak
• Coolant loss - hot-vee crossover pipe crack

It depends on the car's condition and mileage. A GT R is typically worth £100,000-£195,000 - a rebuilt M178 LS2 engine (£11,000-£19,000) 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 (timing chain, turbo actuator, crossover pipe) may be more economical than a full replacement. GT R Pro and low-mileage cars command significant premiums , making engine replacement a sound investment.

• Vehicle worth £100,000-£150,000: rebuilt engine viable for good condition cars
• Vehicle worth £150,000+: rebuilt engine usually justifies cost
• Preventative repairs: often more economical than full replacement

The M178 LS2 in the GT R produces 577-585 hp - significantly more than the base GT (462 hp) and GT S (510 hp). It features upgraded turbos with larger compressor wheels capable of shifting 1,100 kg of air per hour (up from 900 kg in the GT R) , increased boost pressure (1.35 bar vs 1.2 bar) , revised camshafts and exhaust manifolds, and larger intercoolers . The GT R also uses a dry-sump oiling system (shared with other M178 variants) and is hand-built under AMG's "One Man, One Engine" philosophy .

• GT R (M178 LS2): 577-585 hp, 1.35 bar boost, larger turbos
• Base GT (M178): 462 hp, 1.2 bar boost
• GT S (M178 LS1): 510-522 hp

Power loss in the GT R is most commonly caused by turbo actuator failure, which sends the car into limp mode . An NHTSA document identifies intermittent reduced power (no boost reading) as a known issue, recommending checks of wastegate linkage, pressure transducer, and vacuum supply . Other causes include boost leaks from the hot-vee intercooler system, timing chain stretch causing cam timing drift, and carbon buildup on intake valves. A diagnostic check with Mercedes STAR/XENTRY or compatible equipment is essential to identify the exact cause.

• Turbo actuator failure - most common cause of limp mode
• Timing chain stretch - power loss + rattling
• Boost leaks - from intercooler or charge air pipes