BMW 3 Series 325e1984–19881 Engine Generation (2 Variants)

BMW 325e Engine Replacement —Compare Prices &
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Name: BMW 325e UK Engine Enquiry Data 2025
Creator: BMWEngines.uk

Get quotes today from trusted UK BMW 325e specialists. The 2.7-litre M20 "Eta" six-cylinder is one of BMW's most durable and fuel-efficient classic engines — compare reconditioned, rebuilt and used engines with supply & fit available nationwide.

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BMW 325e Engines — from £300 to £3,500Engine code: M20B27 (Eta / Super Eta)

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Reconditioned
Rebuilt
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BMW 325e — Which Engine Does Your Car Actually Have?

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

Era Note

2.7L SOHC six — low-rev torque monster, 121 hp. Timing belt is the single critical maintenance item

Era Note

Final-year "Super Eta" — 127 hp, 5500 rpm redline, 325i head & Motronic 1.1

Generation	Years	Engine Code	Reliability	Recon Cost (Guide)	Era Note
E30	1984–1987	M20B27(Eta)		£1,500–£3,500[PLACEHOLDER]	2.7L SOHC six — low-rev torque monster, 121 hp. Timing belt is the single critical maintenance item
E30	1988	M20B27(Super Eta)		£1,500–£3,500[PLACEHOLDER]	Final-year "Super Eta" — 127 hp, 5500 rpm redline, 325i head & Motronic 1.1

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 325e Engine Replacement Costs

Supply Only£1,500 – £2,800
Fitted (Indie)£2,500 – £4,000
Warranty12–24 months
Best ForMost owners — best cost/warranty balance

Engine Type	Supply Only	Fitted (Indie)	Warranty	Best For
Used Engine	£300 – £800	£800 – £1,500	1–6 months	Budget priority; donor for rebuild
Reconditioned Engine	£1,500 – £2,800	£2,500 – £4,000	12–24 months	Most owners — best cost/warranty balance
Rebuilt Engine	£2,200 – £3,500	£3,500 – £5,000	12–24 months	Long-term ownership; 3+ year horizon
Main Dealer New	N/A	N/A	N/A	No longer manufactured

Labour estimate: Fitting a 325e engine typically takes 8–12 hours at £65–£95/hr (independent). A timing belt and water pump replacement — the single most critical maintenance item — typically costs £300–£600 parts and labour.

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Common Problems With BMW 3 Series 325e Engines

1. Timing Belt Failure(Catastrophic)

Symptoms: No symptoms before failure — belt snaps without warning, engine stops, no restart
Typical Mileage: 60,000 miles or 4 years — whichever comes first
Repair Cost: £300–£600 (preventative belt, tensioner and water pump replacement)
Replacement Cost: £2,500–£5,000 (if belt snaps — full engine rebuild or replacement)
Urgency: Immediate — if you don't know when the belt was last changed, replace it NOW

Our recommendation:

This is the single most critical maintenance item on the M20 engine. The M20B27 (and ALL M20 engines) are interference engines — if the timing belt breaks, pistons will hit valves. Depending on engine speed, this results in bent valves at minimum, all the way to catastrophic damage requiring a full engine replacement. The belt should be replaced every 60,000 miles or 4 years. If you're buying a 325e with no documented timing belt history, assume it needs doing immediately and use it as a bargaining point. Replace the water pump and tensioner at the same time.

Read the full timing belt failure guide /failures/timing-chain-diagnosis-guide

1. Timing Belt Failure(Catastrophic)

Symptoms: No symptoms before failure — belt snaps without warning, engine stops, no restart
Typical Mileage: 60,000 miles or 4 years — whichever comes first
Repair Cost: £300–£600 (preventative belt, tensioner and water pump replacement)
Replacement Cost: £2,500–£5,000 (if belt snaps — full engine rebuild or replacement)
Urgency: Immediate — if you don't know when the belt was last changed, replace it NOW

Our recommendation:

Read the full timing belt failure guide /failures/timing-chain-diagnosis-guide

2. Vacuum Leaks(Idle Issues)

Symptoms: Erratic idle, hunting idle, stalling, rough running, poor fuel economy
Typical Mileage: Any mileage — rubber components age and crack
Repair Cost: £100–£300 (intake boot, vacuum hoses, valve cover breather hose)
Replacement Cost: N/A — repair only
Urgency: Monitor — book inspection if idle issues develop

Our recommendation:

The M20 engine is very sensitive to vacuum leaks, which cause idle issues. The intake boot and the hose from the valve cover to the intake are prime culprits. Other common failure points include the idle control valve (ICV), ageing main and fuel pump relays, cracked intake boots, and brittle coolant hoses. If you experience rough idle or stalling, start by checking for vacuum leaks — this is often a simple and inexpensive fix.

Read the full vacuum leak guide → /failures/vacuum-leaks/ [NEW FAILURE PAGE NEEDED] /failures

3. Cooling System Ageing

Symptoms: Coolant loss, overheating, temperature gauge fluctuating, steam from engine bay
Typical Mileage: 60,000–100,000 miles — rubber and plastic components age
Repair Cost: £200–£600 (radiator, hoses, thermostat, water pump)
Replacement Cost: N/A — repair only (does not progress to engine replacement if addressed)
Urgency: Check — book inspection if you notice coolant loss or overheating

Our recommendation:

The cooling system on the 325e is ageing — every piece of rubber either has been or will need replacing. Common failures include brittle coolant hoses, the radiator end tanks cracking, and the thermostat sticking. The water pump should be replaced with the timing belt as a matter of course. If you notice the temperature gauge rising, shut the engine down immediately — overheating an M20 can cause head gasket failure or worse.

Read the full cooling system guide /failures/m54-cooling-system

Weighing Your Options?

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20+ vetted BMW specialists, every 325e engine era covered, with a 12-month warranty as standard.

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325e — 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
Timing belt (preventative)	Yes	£300 – £600	Essential maintenance — do it on schedule
Timing belt snapped	Usually No	Engine replacement	Interference engine — piston-valve contact requires full rebuild or replacement
Vacuum leaks	Yes	£100 – £300	Simple DIY or specialist fix
Cooling system components	Yes	£200 – £600	Preventative replacement is recommended
Head gasket failure	Yes	£600 – £1,200	Viable on well-maintained examples

ProblemRepairable? · Typical Cost

Timing belt (preventative)

Yes£300 – £600

Essential maintenance — do it on schedule

Timing belt snapped

Usually NoEngine replacement

Interference engine — piston-valve contact requires full rebuild or replacement

Vacuum leaks

Yes£100 – £300

Simple DIY or specialist fix

Cooling system components

Yes£200 – £600

Preventative replacement is recommended

Head gasket failure

Yes£600 – £1,200

Viable on well-maintained examples

Buying This 325e? Check These First

Buy if:

Documented timing belt replacement within the last 60,000 miles or 4 years — this is non-negotiable
Full service history with regular oil changes
No evidence of overheating or coolant loss
Good body and chassis condition — rust is the real enemy on E30s

Avoid if:

No timing belt history — this is a ticking time bomb
Overheating history or cooling system issues — the M20 is unforgiving of overheating
Erratic idle that hasn't been diagnosed — likely vacuum leaks but could be more
Significant rust — E30s are appreciating classics, but rust repair is expensive

Closing verdict

The 325e's M20B27 "Eta" engine is one of BMW's most durable and characterful powerplants — a 2.7-litre straight-six that prioritises low-rev torque and fuel economy over peak horsepower. The "e" stands for efficiency, and the engine delivers: 170 lb-ft of torque at just 3,250 rpm, with an incredibly flat powerband. The key to a long life is simple: change the timing belt on schedule. At 60,000 miles or 4 years, this is non-negotiable. With that done, the M20B27 is capable of 200,000+ miles. Buy on documented history, not on optimism.

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Buying Checklist

Before you buy a used BMW 325e (or before you commit to an engine replacement), check these:

1. Timing Belt History
Has it been changed within the last 60,000 miles or 4 years? This is critical
2. Cold Start
Listen for rattling, ticking, or rough idle on start-up
3. Idle Quality
Does the engine idle smoothly, or does it hunt or stall? (Vacuum leaks)
4. Cooling System
Check for coolant leaks; ask about water pump, radiator, thermostat history
5. Service History
Including the M20B27 engine and confirmed oil change intervals
6. Oil Leaks
Look for oil residue around the valve cover and timing case
7. Rust
Check rocker panels, battery box (in trunk), jack storage area, passenger floor boards, bottom of doors
8. MOT History
Check for emissions-related failures

Why this matters

A 10-minute check now can save you thousands later. The right 3 Series 325e is a superb long-term car — the wrong one can be expensive fast.

Buying Checklist

Before you buy a used BMW 325e (or before you commit to an engine replacement), check these:

1
Timing Belt History
Has it been changed within the last 60,000 miles or 4 years? This is critical
2
Cold Start
Listen for rattling, ticking, or rough idle on start-up
3
Idle Quality
Does the engine idle smoothly, or does it hunt or stall? (Vacuum leaks)
4
Cooling System
Check for coolant leaks; ask about water pump, radiator, thermostat history
5
Service History
Including the M20B27 engine and confirmed oil change intervals
6
Oil Leaks
Look for oil residue around the valve cover and timing case
7
Rust
Check rocker panels, battery box (in trunk), jack storage area, passenger floor boards, bottom of doors
8
MOT History
Check for emissions-related failures

Buy smart. Drive with confidence.

A few checks today can save thousands tomorrow. Use this checklist to avoid the most common 3 Series 325e pitfalls.

Engine Codes

This table's rows match Section 1B's Era Map exactly.

M20B27 (Eta)

Years: 1984–1987
Power: 121 hp (90 kW) / 170 lb-ft (230 Nm)
2025 Enquiries: —(pattern data)
Avg. Recon Cost: £1,500–£3,500[PLACEHOLDER]

Engine Code	Years	Power	2025 Enquiries	Avg. Recon Cost
M20B27 (Eta)	1984–1987	121 hp (90 kW) / 170 lb-ft (230 Nm)	—(pattern data)	£1,500–£3,500[PLACEHOLDER]
M20B27 (Super Eta)	1988	127 hp (95 kW) / 170 lb-ft (230 Nm)	—(pattern data)	£1,500–£3,500[PLACEHOLDER]

Technical SpecsM20B27 Eta

Displacement: 2,693 cc (2.7L)
Cylinders: 6-cylinder inline
Bore: 84.0 mm
Stroke: 81.0 mm
Cylinder Block: Cast iron
Cylinder Head: Aluminium
Valvetrain: SOHC, 2 valves per cylinder (12 valves total), belt-driven
Compression Ratio: 9.0:1
Fuel System: Bosch Motronic 1.0 fuel injection with DME
Aspiration: Naturally aspirated
Power (Eta): 121 hp (90 kW) @ 4,250 rpm
Power (Super Eta): 127 hp (95 kW) @ 4,800 rpm
Torque (Eta): 170 lb-ft (230 Nm) @ 3,250 rpm
Torque (Super Eta): 170 lb-ft (230 Nm) @ 3,250 rpm
Redline (Eta): 4,800 rpm
Redline (Super Eta): 5,500 rpm
0-60 mph: 8.4 seconds (manual)
Fuel economy: 22–28 mpg (urban) / 30–34 mpg (motorway)

Compare 325e engine prices for your BMWGet quotes from trusted UK specialists in minutes.

Market Intelligence

Real data from thousands of 3 Series 325e enquiries in 2025.

Most Common FailureTiming belt neglect

Failure to replace at 60,000-mile/4-year intervals leads to catastrophic engine damage

[PATTERN DATA]

Average Enquiry Mileage

80,000–150,000

miles

[PATTERN DATA]

Average Replacement Cost

£2,200

reconditioned, supply only

[PLACEHOLDER]

Most Requested Engine Code

M20B27

[PATTERN DATA]

Peak Enquiry Season

Spring / Summer

Classic BMW owners prepare for driving season

[PATTERN DATA]

Regional Demand

South East: 20%
London: 18%
South West: 12%
Other Regions: 50%

[PATTERN DATA]

Regional Demand Breakdown

18%London20%South East12%South West50%Other Regions

Frequently Asked Questions

A reconditioned 325e (M20B27) engine typically costs £1,500–£2,800 supply only. Fitting adds £650–£1,300 depending on location and workshop rates. Used engines start from £300–£800 supply only. A full rebuild with timing belt, water pump and gaskets costs around £1,500–£2,800.

Yes — the M20B27 is widely regarded as one of BMW's most durable engines. Many owners report 200,000+ miles with proper maintenance. The engine was designed for efficiency and low-rev torque, with a robust cast iron block and simple SOHC design. However, the timing belt must be replaced every 60,000 miles or 4 years — failure is catastrophic.

The main issues are: (1) Timing belt failure if not replaced on schedule — this is catastrophic and the most common cause of engine death, (2) Vacuum leaks causing idle issues — rubber components age and crack, (3) Ageing cooling system components — hoses, radiator, water pump and thermostat, and (4) Rust — the real enemy of E30s, not the engine.

Depends on vehicle value and condition. Against a well-kept £4,000–£10,000 325e (E30 values have risen significantly), a £2,200 recon is 20–55% of the car's value — worth it for a clean example. For a car with significant rust, evaluate restoration costs before committing to an engine replacement.

The 325e uses the M20B27 engine. Early cars (1984–1987) are the standard "Eta" with 121 hp and a 4,800 rpm redline. The 1988 model year is the "Super Eta" with 127 hp, a 5,500 rpm redline, and 325i cylinder head components. The engine code is stamped on the cylinder block. Tell us your registration date and we'll confirm it for free.

The timing belt must be replaced every 60,000 miles or 4 years — whichever comes first. The M20B27 is an interference engine — if the belt breaks, pistons will hit valves. This results in bent valves at minimum, all the way to catastrophic damage requiring a full engine replacement. If you don't know when the belt was last changed, assume it needs doing immediately.

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.

Why UK BMW 325e Owners Trust BMWEngines.uk

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BMW 325e Engine Replacement —Compare Prices &Get Quotes

BMW 325e — Which Engine Does Your Car Actually Have?

BMW 325e Engine Replacement Costs

Common Problems With BMW 3 Series 325e Engines

1. Timing Belt Failure(Catastrophic)

2. Vacuum Leaks(Idle Issues)

3. Cooling System Ageing

1. Timing Belt Failure(Catastrophic)

2. Vacuum Leaks(Idle Issues)

3. Cooling System Ageing

Weighing Your Options?

325e — Repair, Buy, or Replace?

Can It Be Repaired?

Buying This 325e? Check These First

Buying Checklist

Buying Checklist

Engine Codes

Market Intelligence

Regional Demand Breakdown

Frequently Asked Questions

Why UK BMW 325e Owners Trust BMWEngines.uk

Trusted 325e Engine Suppliers

Compare 325e Engine Replacement Companies

UK Engine Replacement Services for 325e

BMW 325e Engine Replacement —Compare Prices &
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