BMW M50B25 engine report
BMW M50B25 · 325i (E36)
2.5 LPetrolInline-61990–1995
86/100
[excellent]
Only worth it at the right price
Worth buying, but only on the right car.
ExcellentGoodSolidRiskyAvoid
- Known issues
- 5
- Critical
- 1
- Sources
- 27
Verdict
These burn oil, and it comes up very often.
Ask how much gets topped up between services and check whether anyone has been tracking it. The VANOS solenoid is the other common trouble spot, usually not a disaster, but worth listening for on a test drive along with anything that feels rough. Oil leaks and the water pump are rarer and not cheap. Ringland failure is the one to actually fear, so unless the car is genuinely cheap and has been checked over properly, walk.
Specs
- Displacement
- 2.5 L
- Layout
- Inline-6
- Fuel
- Petrol
- Production
- 1990 – 1995
- Chassis
- E36
- Fitted
- 1990–1995
Known issues
5 confirmed · sorted by severity
CriticalPiston ringland failure
Piston ringland cracking under high cylinder pressure/heat, common on tuned forced-induction engines.
Symptoms
- Power Loss
- Smoke (White/Blue/Black)
- Misfire
How often
Occasional · Design weakness. Does not normally destroy the engine. Not safely drivable.
Evidence
2 owner reports back this, confidence 40/100.
ModerateExcessive oil consumption
Worn valve stem seals, piston rings, or a clogged PCV/oil separator system causing oil consumption above manufacturer spec.
Symptoms
- Oil Consumption
- Smoke (White/Blue/Black)
How often
Very common · Age-related wear. Does not normally destroy the engine. Still drivable.
Evidence
6 owner reports back this, confidence 45/100.
ModerateWater pump failure
Water pump seal or bearing failure (mechanical or electric pump), causing coolant loss.
Symptoms
- Coolant Loss
- Warning Light
How often
Rare · Age-related wear. Does not normally destroy the engine. Still drivable.
Evidence
1 owner report backs this, confidence 50/100.
LowVariable valve timing solenoid/actuator failure
VANOS/VTEC/VVT-style variable valve timing solenoids or actuators fail or clog, causing rough idle, rattle on start, or reduced power.
Symptoms
- Rough Idle
- Reduced Power Mode
- Warning Light
How often
Common · Age-related wear. Can destroy the engine if ignored. Still drivable.
Evidence
3 owner reports back this, confidence 45/100.
LowOil leak from seals or gaskets
Valve cover gasket, rear main seal, or front main seal degradation causing external oil leaks.
Symptoms
- Oil Consumption
How often
Rare · Age-related wear. Does not normally destroy the engine. Still drivable.
Evidence
1 owner report backs this, confidence 50/100.
- Critical
- High
- Moderate
- Low
Piston ringland failurefrom 173k km
Excessive oil consumptionfrom 97k km
Water pump failurefrom 79k km
Oil leak from seals or gasketsfrom 79k km
Buying checklist
0 of 5 checked
Sources
Updated 15 Sept 2026 · scoring v2.7
This report combines 27 owner posts, forum threads and official records. An issue only makes the list once the evidence is strong enough, an official recall on its own or several independent owner reports, and the score weighs how often each problem happens against how bad it is when it does.