EXPERT IN AUTO PARTS
17 September 2025 (updated) Table of Contents
The timing chain in the 1.6 THP engines of the Peugeot 508 shows frequent faults and can show the first signs of wear after 80,000 km. The 156 hp variants are particularly affected, with the timing chain causing rattling noises on cold starts and the engine running unevenly. The reliability of this engine component is limited, as the chain wears prematurely due to high loads and insufficient lubrication. Symptoms such as metallic noises from the engine compartment, especially in the first few minutes after starting, indicate an elongated or damaged timing chain. The service life of the original timing chain is often less than 150,000 km, which is considered below average for modern engines.
Regular maintenance is crucial for the early detection of timing chain problems. The sensitive Peugeot 508 timing chain tensioners require regular checks every 20,000 km and the use of high-quality engine oils with the correct viscosity. For diagnosis, the engine should be checked for unusual noises at operating temperature, with a stethoscope on the timing chain box providing useful information. At the first sign of wear, the entire timing chain, including tensioners and guide rails, must be replaced immediately to avoid serious engine damage.
The automatic transmission of the Peugeot 508 shows typical weak points, which manifest themselves in jerky gear changes or complete failure to change gear. Models from 2011 onwards are particularly affected by these complaints, with the problems usually occurring between 60,000 and 100,000 km. The most common symptoms include delayed gear changes, jerking when starting off and remaining in one gear with no further shift options. The automatic transmission no longer shifts properly, which can lead to significant breakdowns and safety risks. The faults often manifest themselves through error codes in the control unit, which indicate defective sensors, worn clutches or problems with the transmission control unit.
A systematic check is essential for the timely detection of transmission problems. The complex Peugeot 508 automatic transmission control units require regular software updates and transmission fluid flushes every 60,000 km. Diagnosis is carried out using special diagnostic equipment that reads fault codes and displays live data from the transmission sensors. Preventive measures include changing the gearbox oil regularly, checking the electrical connections and avoiding aggressive driving to prolong the life of the gearbox.
Article number: 837522
£ 383,15
price incl. 20% VAT, free delivery
-52%
ELRING Gasket, cylinder head
1,4 mm, Ø: 76,3 mm, Multilayer Steel (MLS), Notches/Holes Number: 4
Article number: 718.341
compared to
RRP
£ 45,60
£ 21,82
price incl. 20% VAT, excl. delivery costs
-19%
FEBI BILSTEIN Rocker cover
with gasket/seal
Article number: 102602
compared to
RRP
£ 176,99
£ 142,41
price incl. 20% VAT, free delivery
BOSCH Fuel filter
Filter Insert
Article number: F 026 402 359
£ 17,15
price incl. 20% VAT, excl. delivery costs
Article number: VE18320
More
£ 25,60
£ 25,60 for 1 litre
price incl. 20% VAT, excl. delivery costs
The Start-Stop system of the Peugeot 508 does not work reliably and shows frequent failures, especially in older vehicles. The technology does not start or deactivates spontaneously, which is mainly caused by a weak battery after 40,000-80,000 km. Typical symptoms are a permanently illuminated Start-Stop indicator light in the dashboard and the inability of the system to switch off the engine automatically. The reliability of the system is highly dependent on battery capacity, engine temperature and various vehicle parameters. Other causes may be defective sensors, dirty battery terminals or problems with the air conditioning system, as the system is only activated under optimum conditions.
Professional maintenance is required to ensure that the Start-Stop system functions properly. The demanding Peugeot 508 Start-Stop batteries require special AGM technology and regular capacity checks every 30,000 km. Diagnosis begins with checking the battery voltage and capacity, followed by checking all relevant sensors such as engine temperature, air conditioning and steering wheel position. Preventive treatment includes regular cleaning of the battery terminals, timely battery replacement and updating the control unit software.
The head-up display of the Peugeot 508, especially in GT variants, frequently shows defects and does not extend from the dashboard panel. These faults typically occur after 50,000-90,000 km and are manifested by mechanical blockages or electronic faults. The most common symptoms include a display that remains in the folded position, flickering or distorted displays and complete system failures. The head-up display does not function properly, which can affect safety as important driving information is no longer displayed in the driver's field of vision. The service life of the mechanical components is often limited, as the delicate motors and guide rails are subject to dust and temperature fluctuations.
A professional inspection is necessary to correctly diagnose head-up display problems. The precise Peugeot 508 Head-Up Display mechanisms require regular calibration and careful cleaning of the optical components. Diagnostics include checking the electrical connections, calibrating the display position and checking the mechanical movements. Solutions range from updating the software and cleaning the guide rails to complete replacement of the display unit in the event of serious mechanical defects.
The air conditioning system of the Peugeot 508 does not cool sufficiently and frequently malfunctions, especially in the diesel versions such as the 2.0 HDI and 1.5 BlueHDI. These problems manifest themselves in poor cooling performance, unusual noises or complete failure of the cooling function. Typical causes are leaking refrigerant lines, defective compressors or dirty condensers, which occur particularly after 60,000-100,000 km. The air conditioning system no longer cools effectively, which significantly impairs driving comfort and is particularly problematic in the SW models due to the larger interior space. Symptoms such as warm air from the air vents, misted-up windows or oily stains under the vehicle indicate various defects in the air conditioning system.
Regular maintenance is essential for the air conditioning system to function optimally. The sensitive Peugeot 508 air conditioning compressors require annual checks and regular refrigerant charges every 2-3 years. Diagnosis is carried out by measuring the pressure in the refrigerant circuit, visually checking for leaks and testing the function of all components. Preventive measures include regular operation of the air conditioning system even in winter, changing the cabin filter every 15,000 km and professional disinfection of the evaporator to prevent the build-up of bacteria.
Article number: EK720
£ 125,70
price incl. 20% VAT, free delivery
FANFARO Transmission fluid
75W-80, Capacity: 1l
Article number: FF8710-1
More
£ 12,16
£ 12,16 for 1 litre
price incl. 20% VAT, excl. delivery costs
BOSCH Fuel filter
In-Line Filter, 8mm, 8mm
Article number: 0 450 902 161
£ 7,43
price incl. 20% VAT, excl. delivery costs
-5%
Article number: MN7703-4
More
compared to
RRP
£ 22,86
£ 21,56
£ 5,39 for 1 litre
price incl. 20% VAT, excl. delivery costs
-63%
Article number: KP15656XS
compared to
RRP
£ 254,23
£ 92,51
price incl. 20% VAT, excl. delivery costs
Based on the experiences of Peugeot 508 drivers, the following additional problems occur:
| Strengths | Weak points |
|---|---|
| Comfortable chassis | Timing chain on 1.6 THP engines |
| Spacious interior | Automatic transmission problems |
| Modern assistance systems | Start-Stop system failures |
| Attractive design | Head-up display defects |
| Good engine selection | Air conditioning malfunctions |
| High-quality workmanship | Bluetooth connectivity issues |
| Economical diesel engines | Electronics vulnerability |
| Extensive safety package | High repair costs |
The Peugeot 508 presents itself as a technologically advanced vehicle with an appealing design and good driving comfort. Nevertheless, there are typical weak points, particularly in the electronic systems and specific engine components. Most problems can be avoided or at least their effects minimized by regular maintenance and preventive measures. The timing chain in THP engines and the complex electronic systems, which require professional diagnosis and maintenance, require particular attention.
BOSCH Tyre pressure sensor (TPMS)
VALEO Clutch kit
with dual-mass flywheel, with central slave cylinder, with screw set, with lock screw set, without sensor, 235mm
FEBI BILSTEIN Thermostat
Opening Temperature: 105°C, with gasket/seal, with housing
MOBIL Engine oil
5W-40, 5l
PIERBURG Oil Pump
with electrical oil pressure valve
BOSCH Xenon bulb
D1S, 85V, 35W, 4300K
INA Alternator Freewheel Clutch
Requires special tools for mounting
BERU Spark plug
12 ZR-6 SPP2-1, M12x1,25, Spanner Size: 14 mm Bi-Hex
