E46Forum.co.uk

Think you're saving money by cutting corners? Think again. Here's how seemingly innocent maintenance myths can lead to catastrophic (and expensive) failures in your E46.

1. "Filters are just filters, right?"
Potential Cost of Negligence: £1,500+

The Myth:

• Cheap air, oil, and fuel filters are just as good
• Filter quality doesn't really matter
• Extending filter change intervals is fine
• Aftermarket filters are always equivalent to OEM

What Actually Happens:
1. Using cheap £5 filters instead of proper £20 ones leads to:

• MAF sensor contamination
• Airflow meter malfunction
• Fuel injector clogging
• Accelerated engine wear

Prevention:

• Use only OEM or high-quality equivalent filters
• Stick to recommended change intervals
• Inspect filters regularly for unusual debris
• Consider upgrading to performance filters for better protection

True Cost if Ignored:

• MAF sensor replacement: £300
• Fuel injector set: £600
• Engine wear: £500+
• Diagnostics and labour: £200+

2. "Why change spark plugs early?"
Potential Cost of Negligence: £2,000+

The Myth:

• Spark plugs and coils last forever
• You can wait until they fail completely
• Cheap plugs work just as well
• Misfires aren't a big deal

What Actually Happens:
1. Neglecting a £100 spark plug and coil refresh leads to:

• Catalytic converter damage
• O2 sensor failure
• Poor fuel economy
• Starting and idle issues

Prevention:

• Change spark plugs every 60,000 miles or 4 years
• Inspect coils regularly
• Use only OEM or equivalent quality parts
• Address any misfire immediately

True Cost if Ignored:

• Catalytic converter: £800
• O2 sensors: £400
• Fuel waste: £300+
• Diagnostics and labour: £500+

3. "CCV? That's just a minor thing."
Potential Cost of Negligence: £2,500+

The Myth:

• Crankcase ventilation isn't important
• Oil smoke from the exhaust is normal
• CCV issues don't affect performance
• It's too complicated to maintain

What Actually Happens:
1. Ignoring a £200 CCV system service leads to:

• Oil seal failures
• Turbocharger damage (in diesels)
• Increased oil consumption
• Vacuum leaks affecting performance

Prevention:

• Regular inspection of CCV components
• Replace CCV system at recommended intervals
• Address any oil leaks or smoke promptly
• Use quality oil to reduce sludge build-up

True Cost if Ignored:

• Turbocharger replacement: £1,500
• Multiple oil seal replacements: £600
• Excessive oil consumption: £300+
• Diagnostics and labour: £400+

4. "Cold engine? No worries, let's go!"
Potential Cost of Negligence: £3,000+

The Myth:

• Modern engines don't need warm-up
• Revving a cold engine helps it warm faster
• Short trips are fine for the engine
• Oil viscosity doesn't matter in cold weather

What Actually Happens:
1. Consistently driving on a cold engine leads to:

• Accelerated piston ring wear
• Cylinder wall scoring
• Increased fuel injector wear
• Oil sludge build-up

Prevention:

• Allow 30-60 seconds idle time before driving
• Drive gently until engine reaches operating temperature
• Use the correct oil viscosity for your climate
• Avoid short trips where possible

True Cost if Ignored:

• Engine rebuild: £2,500+
• Fuel injector replacement: £600
• Oil-related issues: £400+
• Diagnostics and labour: £500+

5. "Pressure washing the engine bay? Why not!"
Potential Cost of Negligence: £2,000+

The Myth:

• Pressure washing is the best way to clean an engine
• Water can't harm modern electronics
• It's fine to spray directly at components
• A clean engine bay prevents all issues

What Actually Happens:
1. Improper engine bay cleaning leads to:

• Electrical connector corrosion
• ECU water damage
• Sensor failures
• Accelerated rust in hidden areas

Prevention:

• Use gentle cleaning methods (damp cloth, detailing brushes)
• Cover sensitive electronics if using water
• Avoid direct spray on connectors and control units
• Use a water displacing spray after cleaning

True Cost if Ignored:

• ECU replacement: £1,000+
• Multiple sensor replacements: £600
• Wiring harness repairs: £400+
• Diagnostics and labour: £300+

6. "ABS/DSC lights on? No big deal."
Potential Cost of Negligence: £1,500+

The Myth:

• ABS isn't really necessary
• DSC warnings can be ignored
• Sensor issues don't affect braking
• These systems are too complex to maintain

What Actually Happens:
1. Ignoring ABS/DSC warnings leads to:

• Compromised vehicle stability
• Increased stopping distances
• Uneven brake wear
• Potential for loss of control in emergencies

Prevention:

• Address warning lights immediately
• Regular brake system inspections
• Clean ABS sensors when servicing brakes
• Use quality parts for ABS components

True Cost if Ignored:

• ABS module replacement: £800
• Multiple sensor replacements: £400
• Premature brake wear: £300+
• Diagnostics and labour: £200+

7. "AC not cooling well? There's always the sunroof!"
Potential Cost of Negligence: £1,200+

The Myth:
[*]AC doesn't need to be used in winter
[*]Weak cooling is normal in older cars
[*]AC maintenance is a luxury, not a necessity
[*]Recharge kits from auto stores are just as good
[/list]

What Actually Happens:
1. Neglecting AC maintenance leads to:

• Compressor failure
• Evaporator corrosion
• Mould growth in the system
• Increased fuel consumption

Prevention:

• Use AC at least weekly, even in winter
• Annual system check and re-gas
• Address any performance issues promptly
• Regular cabin filter replacement

True Cost if Ignored:

• Compressor replacement: £600
• Evaporator replacement: £400
• System flush and recharge: £200
• Diagnostics and labour: £200+

8. "Transmission oil? It's an automatic, it's fine!"
Potential Cost of Negligence: £3,500+

The Myth:

• Automatic transmissions are maintenance-free
• Transmission fluid lasts the life of the car
• Slight jerking or slipping is normal
• Transmission temperature doesn't matter

What Actually Happens:
1. Neglecting transmission maintenance leads to:

• Internal clutch pack failure
• Valve body wear
• Torque converter damage
• Complete transmission failure

Prevention:

• Change transmission fluid every 50,000-60,000 miles
• Use only the specified fluid type
• Address any shifting issues promptly
• Consider adding a transmission cooler for heavy use

True Cost if Ignored:

• Transmission rebuild: £2,500+
• Torque converter replacement: £600
• Valve body replacement: £400
• Diagnostics and labour: £300+

9. "Washer jets work? No need to clean them."
Potential Cost of Negligence: £800+

The Myth:

• Washer system doesn't need maintenance
• Any washer fluid is fine to use
• Clogged nozzles will clear themselves
• Headlight washers aren't important

What Actually Happens:
1. Neglecting the washer system leads to:

• Pump failure from debris
• Frozen lines in winter
• Damaged windscreen from poor cleaning
• Reduced headlight effectiveness (for xenon systems)

Prevention:

• Use quality washer fluid appropriate for the season
• Clean nozzles and check alignment regularly
• Flush the system annually
• Ensure headlight washers are functional (if equipped)

True Cost if Ignored:

• Washer pump replacement: £150
• Windscreen replacement: £400
• Headlight washer system repair: £250
• Labour and parts: £100+

10. "E46 isn't a museum piece, rust is normal."
Potential Cost of Negligence: £2,500+

The Myth:

• Some rust is normal on older cars
• Undercoating isn't necessary
• Door and boot seals don't need maintenance
• Winter salt wash-offs are overkill

What Actually Happens:
1. Neglecting rust prevention leads to:

• Structural weakness in key areas
• Water ingress causing electrical issues
• Accelerated corrosion of suspension components
• Decreased resale value

Prevention:

• Annual inspection for rust, especially in hidden areas
• Regular underbody cleaning and protection
• Maintain door and boot seals
• Prompt repair of paint chips and scratches

True Cost if Ignored:

• Major body work: £1,500+
• Suspension component replacement: £600
• Electrical repairs due to water damage: £400
• Value depreciation: £500+

Key Takeaways:

• Regular maintenance is always cheaper than repairs
• Use quality parts and fluids
• Address small issues before they become big problems
• Understand your E46's specific needs
• When in doubt, consult a specialist

Recommended Maintenance Schedule:

• Weekly: Visual checks, fluid levels
• Monthly: Detailed underhood inspection
• Every 3 months: Thorough systems check
• Annually: Professional inspection and preventive maintenance