01
BMW M5
Generation/Chassis
F90 LCI
Badge(s)
M5 Competition (625 hp)
Years
2020-2023
BMW S63B44T4 Engine - Replacement Cost, Problems & CompatibilityProblems & Compatibility
The BMW S63B44T4 is the 4.4-litre twin-turbo V8 M engine powering the F90 M5 Competition, F92/F93 M8 Competition, F95 X5M Competition and F96 X6M Competition from 2018 onwards - reconditioned units from approximately £10,000, with demand in line with the broader S63 family.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
Used from
£6,000
Reconditioned from
£10,000
Rebuilt from
£14,000
GB
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Quotes only from vetted UK engine specialists.
Key Specs
BMW S63B44T4 - Specifications at a Glance
Engine Code
S63B44T4
Fuel
Petrol
Configuration
4.4L V8, twin-twin-scroll turbochargers, DOHC 32-valve, Double VANOS, Valvetronic
Power Output
625 hp (460 kW); 553 lb-ft (750 Nm)
Years Produced
2018-present
UK Models Fitted
4 BMW M models - full list in Compatibility below
2025 UK Replacement Requests
Replaced
S63B44T3 - the earlier 600 hp variant
Replaced By
S68B44 - the new V8 with hybrid assistance
Most Common Failure
Timing chain tensioner (improved but still monitored)
Reconditioned Price Range
£10,000-£14,000 supply-only
Vetted UK specialists for S63B44T4 replacements
Minimum 12-month warranty on reconditioned and rebuilt options
Fitted To
Which BMW Models Use the S63B44T4-
**TAG:** Fitted To
| Model | Generation/Chassis | Badge(s) | Years | Link |
|---|---|---|---|---|
 BMW M5 | F90 LCI | M5 Competition (625 hp) | 2020-2023 | |
| BMW M5 | F90 (pre-LCI) | M5 Competition (617 hp) | 2018-2020 | |
| BMW M8 Coupé | F92 | M8 Competition (625 hp) | 2019-present | |
| BMW M8 Gran Coupé | F93 | M8 Competition (625 hp) | 2019-present | |
| BMW M8 Convertible | F91 | M8 Competition (625 hp) | 2019-present | |
| BMW X5M | F95 | X5M Competition (625 hp) | 2020-present | |
| BMW X6M | F96 | X6M Competition (625 hp) | 2020-present |
02
BMW M5
03
BMW M8 Coupé
04
BMW M8 Gran Coupé
05
BMW M8 Convertible
06
BMW X5M
07
BMW X6M
CROSS-BRAND
S63B44T4 is documented across 7 BMW applications spanning BMW M5, BMW M8 Coupé, BMW M8 Gran Coupé, BMW M8 Convertible, BMW X5M, BMW X6M. Registration lookup confirms the exact suffix before quotes are sent.
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Not sure which engine your car has- Enter your registration above - we'll confirm your exact S63B44T4 fitment before any quotes are sent.
Prices
BMW S63B44T4 Engine Replacement Cost (UK)
Condition | Supply Only | Fitted (Independent Specialist) | Typical Warranty |
|---|---|---|---|
Used | £6,000-£10,000 | £7,560-£11,560 | 3-6 months |
Reconditioned | £10,000-£14,000 | £11,560-£15,560 | 12-24 months |
Rebuilt | £14,000-£18,000 | £15,560-£19,560 | 12-24 months |
All figures . Fitted = supply price + labour band below.
Labour Guide
Fitting an S63B44T4 typically takes 18-24 hours at £65-£91/hr (independent M specialist) - confirm exact labour when comparing quotes.
Price Factors
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Common Problems
BMW S63B44T4 Engine Problems - What Actually Fails
Every engine has its weak points. Here are the known issues with the S63B44T4, based on real-world data and verified failure patterns.
Verified issue focus: Timing chain tensioner (improved but still monitored).
1. Timing Chain Tensioner Wear - Improved but Still a Monitoring Point
1. Timing Chain Tensioner Wear - Improved but Still a Monitoring Point
Typical onset:
60,000-100,000 miles (less common than early S63 but still reported)
What happens:
The S63B44T4 uses a revised timing chain tensioner compared to earlier S63 variants, but the design still relies on oil pressure and a spring mechanism that can weaken over time. Cold-start rattle is a warning sign; if ignored, chain slack can lead to timing drift and, in extreme cases, valve-to-piston interference. The T4 variant is more durable than the early S63B44, but tensioner wear is still the most documented mechanical failure.
Repair vs replace:
If caught early (rattle only), tensioner and guide replacement is a manageable repair (£1,500-£2,500). If the chain has jumped, the engine is typically beyond economical repair - a full replacement is the only safe option. Read our full timing chain failure guide
Read more about this issue
2. Hot-Vee Heat Stress - Valve Stem Seals & Plastic Coolant Lines
2. Hot-Vee Heat Stress - Valve Stem Seals & Plastic Coolant Lines
Typical onset:
50,000-90,000 miles
What happens:
The hot-vee layout places the turbos inside the V of the engine, generating extreme heat. Over time, this degrades valve stem seals (leading to oil consumption and blue smoke on start-up) and makes plastic coolant lines around the turbos brittle and prone to cracking. The T4 uses improved materials over earlier S63 engines, but these issues still occur on higher-mileage examples.
Repair vs replace:
Valve stem seal replacement is a labour-intensive job (£3,000-£5,000) and often done alongside other work. Coolant line replacement is cheaper but usually done at the same time. If oil consumption is excessive or the engine has overheated, a reconditioned unit may be more cost-effective. Read our full oil consumption guide
Read more about this issue
3. Turbocharger Wear - Wastegate Rattle & Bearing Play
3. Turbocharger Wear - Wastegate Rattle & Bearing Play
Typical onset:
70,000-120,000 miles
What happens:
The S63's twin-twin-scroll turbos are under constant high-temperature stress. Wastegate bushings wear, causing rattle on deceleration, and turbo bearings can develop play, leading to reduced boost and oil consumption. This is more common on high-mileage examples or cars that have been aggressively tuned.
Repair vs replace:
Turbo refurbishment or replacement is a specialist job (£1,500-£3,000 per turbo). If both turbos are failing and the engine is out for other work, many owners opt for a full reconditioned unit with refreshed turbos already included.
Read more about this issue
Compare rebuilt S63B44T4 prices with the failures already addressed
Engine Variants
How to Confirm You Have the S63B44T4
The S63B44T4 is the final iteration of the S63TU engine family, distinguished from earlier variants by its 625 hp output, specific turbocharger hardware, and updated engine management. It is the engine found in the F90 M5 Competition (post-2020), M8 Competition, and competition-spec X5M/X6M. Where the code appears: - Stamped on a metal plate on the engine block (left-hand side, near the timing cover) - On the V5C logbook under "Engine number" (the first 8 characters will read S63B44T4) - Via BMW VIN decoder - the 7th character of the VIN indicates engine type Commonly confused with: - S63B44T0 - earlier Competition variant with 575 hp (F10 M5 Competition) - S63B44T2 - 600 hp variant (F90 M5 standard, pre-LCI) - S63B44T3 - 600-617 hp variant (F90 M5 pre-Competition, some M8) - S68B44 - new hybrid V8 (X5M/X6M, M5 hybrid)
Not sure which S63 variant you have- Enter your registration above and we'll confirm your exact engine code before sending any quotes.
Easily Confused
S63B44T3
- the earlier 600-617 hp variant found in pre-LCI F90 M5 Competition models. The T4 increased output to 625 hp with revised turbo control and engine mapping, while retaining the same long-block hardware.
Alternative / Next-Gen Code
S68B44
- the new 4.4-litre V8 with mild-hybrid assistance, introduced in the latest X5M/X6M and the next-generation M5. It uses a 48-volt system and produces up to 635 hp - the T4 is the last pure ICE V8 in the high-output M line.
Confirm the exact S63B44T4 fitment
Not sure which S63 variant you have- Enter your registration above and we'll confirm your exact engine code before sending any quotes.
Buying Guide
Buying a Replacement S63B44T4 - What to Choose
Choosing the right replacement route depends on your budget, risk tolerance, and ownership goals. Here's a breakdown of your options.
Used:
A used S63B44T4 can be viable if it comes from a low-mileage, well-maintained car with full documented history. However, these engines are often driven hard; without proof that the timing chain tensioner has been addressed and the turbos are in good health, a used unit is a gamble. Many used S63 engines are sold with known issues. Factor in £2,000-£4,000 for preventative work (tensioner, valve stem seals) if the history is unclear. Link once: /services/used-engines
Reconditioned:
A proper S63B44T4 recon is the gold standard for M5/M8/X5M/X6M owners. A quality recon should include: full strip and inspection, new timing chain tensioner and guides, refreshed valve stem seals, replacement of all plastic coolant lines, turbo refurbishment, new gaskets and seals, and a full test. With a 12-24 month warranty, this gives you a fresh engine with all known weaknesses engineered out - well worth the £10,000-£14,000 supply cost for a high-value M-car. Link once: /services/reconditioned-engines
Rebuilt:
A full rebuild is justified when the original engine has suffered catastrophic failure (chain jump, seized turbos, overheating) and the car is a low-mileage collector or cherished daily driver. An upgraded rebuild should include forged pistons, upgraded rod bearings, a reinforced timing chain guide, and a full cylinder head overhaul. This is specialist work and typically only makes sense for cars with strong residual value (£30,000+). Link once: /services/rebuilt-engines
Supply & Fit Line:
All engines can be supplied and fitted through our network of vetted BMW M specialists nationwide, with 12-month warranty on reconditioned and rebuilt units. Link once: /services/supply-and-fit
Vehicle Value Note:
The S63B44T4 typically sits in F90 M5 Competition, M8, X5M and X6M - cars worth £35,000-£100,000+ depending on age and condition. With a reconditioned supply cost of £10,000-£14,000, replacement is financially viable on most examples. Even a used unit at £6,000-£10,000 is a significant spend, but the high residual values of these M-cars make replacement a sensible investment for owners looking to keep their cars on the road.
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Related Engines
Engines Related to the BMW S63B44T4
Explore engines that are closely related to the BMW S63B44T4, including its predecessor, successor, and key family variants.
Predecessor
S63B44T3
- the earlier 600-617 hp variant found in pre-LCI F90 M5 Competition models. The T4 increased output to 625 hp with revised turbo control and engine mapping, while retaining the same long-block hardware.
Successor
S68B44
- the new 4.4-litre V8 with mild-hybrid assistance, introduced in the latest X5M/X6M and the next-generation M5. It uses a 48-volt system and produces up to 635 hp - the T4 is the last pure ICE V8 in the high-output M line.
FAQ
BMW S63B44T4Frequently Asked Questions
Question 1How much does a BMW S63B44T4 engine replacement cost-
A reconditioned S63B44T4 supply-only costs approximately £10,000-£14,000, with fitted prices ranging from £11,560 to £15,560 depending on labour rates. Used units start at £6,000-£10,000, and full rebuilds run from £14,000-£18,000. Prices are supply-only; fitting adds 18-24 hours at independent M specialist rates. Warranty varies: 3-6 months on used, 12-24 months on reconditioned and rebuilt.
- Prices are supply-only; fitting adds 18-24 hours at independent M specialist rates.
- Warranty varies: 3-6 months on used, 12-24 months on reconditioned and rebuilt.
Question 2What are the most common failures on the S63B44T4-
The most documented issues are timing chain tensioner wear (improved over earlier S63 but still a monitoring point), hot-vee heat-related failures (valve stem seals leading to oil consumption, and cracked plastic coolant lines), and turbocharger wear (wastegate rattle, bearing play). Tensioner replacement is advised at 60k-100k miles as preventative. Valve stem seal replacement can cost £3k-£5k - often done alongside other work. Turbo refurbishment is common on high-mileage examples.
- Tensioner replacement is advised at 60k-100k miles as preventative.
- Valve stem seal replacement can cost £3k-£5k - often done alongside other work.
- Turbo refurbishment is common on high-mileage examples.
Question 3Which BMW models use the S63B44T4 engine-
The S63B44T4 is fitted to F90 M5 Competition (2020-2023), F92/F93 M8 Competition (2019-present), F95 X5M Competition (2020-present), and F96 X6M Competition (2020-present). It produces 625 hp in all applications. Not to be confused with the S63B44T3 (600-617 hp) or the earlier S63B44. The S68 hybrid V8 is the successor engine.
- Not to be confused with the S63B44T3 (600-617 hp) or the earlier S63B44.
- The S68 hybrid V8 is the successor engine.
Question 4Should I buy a used or reconditioned S63B44T4 engine-
A used S63B44T4 can be viable if it has full documented history and proof of tensioner and turbo condition. However, these engines are often driven hard; without evidence of preventative work, a used unit carries significant risk. A reconditioned engine is the safer choice - it typically includes new tensioner, refreshed valve stem seals, replaced coolant lines, and turbo refurbishment, with a 12-24 month warranty. Used is cheaper (£6k-£10k) but factor in £2k-£4k for preventative work. Reconditioned addresses all known weak points and gives peace of mind.
- Used: cheaper (£6k-£10k) but factor in £2k-£4k for preventative work.
- Reconditioned: addresses all known weak points and gives peace of mind.
Question 5How do I confirm my car has the S63B44T4 and not another S63 variant-
Check the engine code stamped on the block (left-hand side near the timing cover) - it will read S63B44T4. The V5C logbook also lists the full engine number, with the first 8 characters identifying the code. Common confusions: S63B44T3 (600-617 hp), S63B44T2 (600 hp), and S63B44 (first generation). Fitting a different TU variant requires ECU and potentially hardware changes.
- Common confusions: S63B44T3 (600-617 hp), S63B44T2 (600 hp), and S63B44 (first generation).
- Fitting a different TU variant requires ECU and potentially hardware changes.
Question 6How long does an S63B44T4 engine typically last-
With meticulous maintenance and early preventative work, these engines can exceed 120,000 miles. The forged internals are robust, and the T4 benefits from the most refined TU iteration. The limiting factors are the timing chain tensioner and hot-vee heat stress. Tensioner and guide replacement recommended at 60k-80k miles. Strict adherence to 5,000-mile oil changes with BMW M-spec oil is critical. Regular inspection of coolant lines and valve stem seals extends lifespan.
- Tensioner and guide replacement recommended at 60k-80k miles.
- Strict adherence to 5,000-mile oil changes with BMW M-spec oil is critical.
- Regular inspection of coolant lines and valve stem seals extends lifespan.
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