Reliability Guide

Common Problems with the
2023 Morgan Plus Four / Plus Six (CX-Generation)

A significant update brought electronic stability control (ESC) as standard, along with driver and passenger airbags, a new AP Racing brake system, revised dampers, and Sennheiser audio. These changes transformed the Plus Four and Plus Six into genuinely modern sports cars without losing their analogue character.

What changed for 2023

  • ESC (electronic stability control) now standard
  • Driver and passenger airbags fitted
  • New AP Racing braking system
  • Revised dampers and bushings for improved comfort
  • Sennheiser audio system available

Common MOT watch-outs

  • !Water ingress remains an inherent trait
  • !Check for updated revision parts on early 2023 builds
4
Known Issues
1
Serious
2
Moderate
1
Minor

All Known Issues

Brake Master Cylinder Recall

SeriousBrakes

A critical safety recall was issued for the brake master cylinder which could lead to a loss of braking pressure.

Est. Repair Cost: £0 (Recall)
Warning Signs:

Long brake pedal travel, Soft pedal

What to Inspect:
  • Verify the brake recall has been signed off by a Morgan dealer.
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BMW B58 Oil Filter Housing & Coolant Leaks

ModerateEngine

The B48/B58 engines can suffer from cracked oil filter housing gaskets and coolant return line leaks. The filter housing sits under the intake manifold, making access difficult and labour-intensive.

Est. Repair Cost: £500–£1,200
Warning Signs:

Oil drips under the car, Coolant loss, Sweet smell from engine bay

What to Inspect:
  • Check under the intake manifold for oil or coolant residue.
  • Inspect coolant return hoses and jubilee clips.
Verified by IsItAGoodCar Research Team

BMW B58 Oil Filter Housing & Coolant Leaks

ModerateEngine

The B48/B58 engines can suffer from cracked oil filter housing gaskets and coolant return line leaks. The filter housing sits under the intake manifold, making access difficult and labour-intensive.

Est. Repair Cost: £500–£1,200
Warning Signs:

Oil drips under the car, Coolant loss, Sweet smell from engine bay

What to Inspect:
  • Check under the intake manifold for oil or coolant residue.
  • Inspect coolant return hoses and jubilee clips.
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Water Ingress & Weatherproofing

MinorBodywork & Rust

Even modern Morgans are not fully watertight. Doors, windscreen seals and hood fitment can allow water into the cabin, particularly at speed in rain. Owners often fit foam strips to door edges.

Est. Repair Cost: £50–£200 (DIY sealing)
Warning Signs:

Wet carpets or seats after rain, Wind noise at motorway speeds, Water dripping from door edges

What to Inspect:
  • Inspect door seals and windscreen perimeter.
  • Check for water stains on interior wood or leather.
  • Test hood fitment in wet conditions.
Verified by IsItAGoodCar Research Team

Buying Tips for 2023 Morgan Plus Four / Plus Six (CX-Generation)

  • Post-2023 cars are significantly safer with ESC and airbags—prioritise these if possible
  • Ask whether the Sennheiser audio system is fitted
  • Verify the brake system has been updated to the AP Racing specification