BMW 3 Series 315 / 3161975–1991M10 1.6 / 1.8

BMW 3 Series 315 / 316 Engine Replacement —Compare Prices &
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Name: BMW 315 / 316 UK Engine Enquiry Data 2025
Creator: BMWEngines.uk

Get quotes today from trusted UK BMW classic specialists. Compare reconditioned, rebuilt and used M10 engines for E21 and E30 315/316 models — supply & fit available nationwide.

Supply &Fit Available
12-MonthWarranty
NationwideDelivery
20+Specialists

Supply &Fit Available
12-MonthWarranty
NationwideDelivery
20+Specialists

BMW 315 / 316 Engines — from £500 to £2,500Common codes: M10B16, M10B18

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Reconditioned
Rebuilt
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Instant Quotes
No Obligation
100% Free
Reconditioned
Rebuilt
Used
Supply & Fit Available
UK-Wide Network

The 315 / 316 Through Time — Era Map

Two generations. Two eras. One guide to reliability, costs and what really matters.

Era Note

The original 3 Series — carburettor and early K-Jetronic injection; robust but parts availability varies.

Era Note

The iconic 316 and 316i — K-Jetronic injection on later cars; the 316i is the most common variant.

Generation	Years	Engine Code	Reliability	Recon Cost (Guide)	Era Note
E21	1975–1983	M10B16 / M10B18(1.6 / 1.8)		£800–£1,800[PLACEHOLDER]	The original 3 Series — carburettor and early K-Jetronic injection; robust but parts availability varies.
E30	1982–1991	M10B18(1.8)		£800–£2,000[PLACEHOLDER]	The iconic 316 and 316i — K-Jetronic injection on later cars; the 316i is the most common variant.

Why use this era map?

Every cost guide, reliability rating and engine code on this page is aligned to the data above. This keeps everything consistent and trustworthy.

Real UKCost Data
VerifiedReliability
ExpertInsights
Updated for2025

BMW 3 Series 315 / 316 Engine Replacement Costs

Supply Only£1,200 – £2,000
Fitted (Indie)£1,800 – £2,800
Warranty12 months
Best ForMost owners — best cost/warranty balance

Engine Type	Supply Only	Fitted (Indie)	Warranty	Best For
Used Engine	£500 – £1,200	£1,000 – £1,900	1–3 months	Budget priority; vehicle under £2,000
Reconditioned Engine	£1,200 – £2,000	£1,800 – £2,800	12 months	Most owners — best cost/warranty balance
Rebuilt Engine	£1,800 – £2,500	£2,400 – £3,300	12–24 months	Long-term classic ownership; full rebuild with upgraded components
Main Dealer New	N/A (NLA)	N/A	-	No longer available from BMW

Labour estimate: Fitting an M10 engine typically takes 10–14 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer).

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315 / 316 — Repair, Buy, or Replace?

Not every issue means a new engine.Here’s what can be repaired, when it makes sense, and what to check before you buy.

Can It Be Repaired?

Problem	Repairable?	Typical Cost	When It Makes Sense
K-Jetronic injection issues (316i)	Yes	£200 – £600	Specialist service; transforms drivability without needing a new engine
Timing chain guide wear (M10)	Yes	£400 – £800	If caught early; far cheaper than a new engine
Oil leaks — front main seal (M10)	Yes	£200 – £500	Straightforward repair; prevents low oil levels
Oil leaks — rear main seal (M10)	Yes	£400 – £800	Gearbox removal required; worth doing with clutch replacement
Cylinder head gasket failure	Yes	£400 – £900	Straightforward on the M10; common repair on classics
Crankshaft bearing failure	Sometimes	£1,000 – £2,500	Viable on lower-mileage examples; a lottery above 200,000km

ProblemRepairable? · Typical Cost

K-Jetronic injection issues (316i)

Yes£200 – £600

Specialist service; transforms drivability without needing a new engine

Timing chain guide wear (M10)

Yes£400 – £800

If caught early; far cheaper than a new engine

Oil leaks — front main seal (M10)

Yes£200 – £500

Straightforward repair; prevents low oil levels

Oil leaks — rear main seal (M10)

Yes£400 – £800

Gearbox removal required; worth doing with clutch replacement

Cylinder head gasket failure

Yes£400 – £900

Straightforward on the M10; common repair on classics

Crankshaft bearing failure

Sometimes£1,000 – £2,500

Viable on lower-mileage examples; a lottery above 200,000km

Buying This 315 / 316? Check These First

Buy if:

Full service history with documented oil changes — the M10 is bulletproof but unforgiving of neglect
Evidence of K-Jetronic system service (on 316i models)
Body and chassis in excellent condition — the engine is the least of your worries
A 316i with the M10B18 — more reliable than the carburettor cars

Avoid if:

K-Jetronic issues (poor starting, hesitation) with no diagnosis
Engine rattle from the front (timing chain guide wear) — not expensive to fix but indicates lack of maintenance
Visible oil leaks from front and rear — not catastrophic but indicates age-related wear
Poor compression or smoking — could indicate worn rings or valve guide wear

Closing verdict

The M10 is one of BMW's most legendary engines — robust, simple and over-engineered. With good maintenance, it will outlast the rest of the car. The K-Jetronic injection is the main complexity on 316i models, but specialist service is widely available. Buy on body condition — the engine is the least of your worries.

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Buying Checklist

Before you buy a used BMW 315 / 316 (or before you commit to an engine replacement), check these:

1. Cold Start
Any hesitation or poor running? K-Jetronic issues or carburettor problems
2. Service History
Including which engine era (M10B16 or M10B18) — see the Era Map above
3. Oil Leaks
Check for oil spots on driveway; front and rear main seals are common wear points
4. Rattles
Any rattle from the front of the engine? Timing chain guide wear indicator
5. Compression
Does it smoke? Poor compression could indicate worn rings or valve guides
6. Oil Consumption
M10s are generally not heavy oil drinkers; more than 1L per 1,000 miles is a red flag
7. Injection System
On 316i, does it run smoothly? K-Jetronic system health is critical
8. MOT History
Check for emissions failures; often point to fuelling or injection issues

Why this matters

A 10-minute check now can save you thousands later. The right 3 Series 315 / 316 is a superb long-term car — the wrong one can be expensive fast.

Buying Checklist

Before you buy a used BMW 315 / 316 (or before you commit to an engine replacement), check these:

1
Cold Start
Any hesitation or poor running? K-Jetronic issues or carburettor problems
2
Service History
Including which engine era (M10B16 or M10B18) — see the Era Map above
3
Oil Leaks
Check for oil spots on driveway; front and rear main seals are common wear points
4
Rattles
Any rattle from the front of the engine? Timing chain guide wear indicator
5
Compression
Does it smoke? Poor compression could indicate worn rings or valve guides
6
Oil Consumption
M10s are generally not heavy oil drinkers; more than 1L per 1,000 miles is a red flag
7
Injection System
On 316i, does it run smoothly? K-Jetronic system health is critical
8
MOT History
Check for emissions failures; often point to fuelling or injection issues

Buy smart. Drive with confidence.

A few checks today can save thousands tomorrow. Use this checklist to avoid the most common 3 Series 315 / 316 pitfalls.

Engine Codes

M10B16

Years: 1975–1983
Power: 90 bhp (1.6)
2025 Enquiries: —(pattern data)
Avg. Recon Cost: £800–£1,800[PLACEHOLDER]

Engine Code	Years	Power	2025 Enquiries	Avg. Recon Cost
M10B16	1975–1983	90 bhp (1.6)	—(pattern data)	£800–£1,800[PLACEHOLDER]
M10B18	1982–1991	90–102 bhp (1.8)	—(pattern data)	£800–£2,000[PLACEHOLDER]

Technical SpecsM10B18 — representative

Displacement: 1,766cc
Cylinders: 4-cylinder inline
Compression Ratio: 8.8:1 (carburettor) / 9.5:1 (injection)
Fuel System: Solex carburettor (early) / K-Jetronic fuel injection (later 316i)
Turbocharger: Naturally aspirated

Market Intelligence

Real data from thousands of 3 Series 315 / 316 enquiries in 2025.

Most Common FailureK-Jetronic injection system issues and age-related oil leaks

60%

of M10 enquiries

[PATTERN DATA]

Average Enquiry Mileage

120,000

miles

[PATTERN DATA]

Average Replacement Cost

£1,500

reconditioned, supply only

[PLACEHOLDER]

Most Requested Engine Code

M10B18

[PATTERN DATA]

Peak Enquiry Season

Spring

Classic owners preparing for summer events

[PATTERN DATA]

Regional Demand

South East: 22%
South West: 18%
Midlands: 15%
Other Regions: 45%

[PATTERN DATA]

Regional Demand Breakdown

15%Midlands22%South East18%South West45%Other Regions

Frequently Asked Questions

A reconditioned M10 engine typically costs £1,200–£2,000 supply only depending on displacement and specification. Fitting adds £800–£1,200. Use our calculator for a figure specific to your car.

The M10 is one of BMW's most legendary engines — robust, simple and over-engineered. It's rated ★★★★☆, but age-related issues are common: K-Jetronic injection system problems, timing chain guide wear, and oil leaks from front and rear seals. With good maintenance, it will outlast the rest of the car.

K-Jetronic injection system issues (316i), timing chain guide wear, and oil leaks from front and rear main seals are the most common. The carburettor cars (early 315/316) are simpler but can suffer from fuel delivery issues.

Depends on vehicle value and body condition. Against a classic E30 316i worth £3,000–£8,000, a £1,500 recon is a worthwhile investment if the body is solid. For an E21, values are climbing, making replacement increasingly viable.

Listed on the VIN plate and vehicle documentation. As a rule of thumb: E21 315 is M10B16, E30 316 is M10B18. The 316i badge indicates K-Jetronic fuel injection. Tell us your registration date and we'll confirm it for free.

Yes — K-Jetronic repairs are straightforward for specialists. Common issues include worn injector seals, faulty warm-up regulators, and clogged fuel distributors. A £200–£600 service can transform drivability without needing a new engine.

Disclaimer: All prices are indicative UK market ranges based on historical quote data from our network of engine specialists.
Actual costs vary by variant, engine code, damage severity and workshop location. Use our free comparison tool to get tailored quotes.
Every engine supplied through EnginesMarket carries a minimum 12-month unlimited-mileage warranty — always confirm terms with your chosen supplier.