The 2.0-litre XU10J4RS engine used in the 306 GTI-6 and Rallye is unchanged between the two models and the three phases of the car's life. It's a robust unit, but with one major caveat: the timing belt.
Peugeot originally specified a 70,000-mile interval before dropping this to 40,000 miles or five years. Even then, plenty of belts snapped before the car reached the 40,000-mile mark and left owners with an expensive fix. It's now reckoned a new belt every 30,000 or three years is the safe limit. With any GTI-6 or Rallye you're thinking of buying, check the service records very closely for receipts to prove when the timing belt was last changed, and look for evidence the water pump was swapped at the same time. Even with cars where this work has been carried out, you should still reckon on replacing the belt and pump as routine service items to be on the safe side for around £300 at a specialist.
Any car with a ticking noise that rises as the engine is revved has probably had a snapped timing belt and poor repairs. Some noise from the fuel injectors when the engine is cold is common, but this will stop when the engine warms through.
If the XU10J4RS engine doesn't idle smoothly from cold, a new idle control valve and stepper motor should solve it. Make sure you use a correct and original spec Magnetti Marelli unit so it lasts a long time - aftermarket items are known to fail quickly.
As well as the water pump, the cooling system in the GTI-6 should be inspected carefully. Keep an ear out for the thermostatic cooling fans switching on when the engine begins to get hot. The cooling system is fragile and radiators corrode. Replacement radiators are easy to fit and many owners upgrade to an aftermarket aluminium item for improved efficiency.
With your head still under the bonnet, check the area where the top engine mount fixes to the bodyshell as it can crack and let the engine start to move unnecessarily.
Air-con pipes corrode and are also prone to damage from underneath as they sit low to the ground. Few cars will have functioning air con as a result as many owners don't bother to spend the £300 to replace pipes that will almost inevitably be damaged again.
A heavy clutch was common when new and it gets heavier with age as the routing of the hydraulic pipes passes close to the exhaust and the cable's grease dries out on right-hand drive cars. Replacing the cable will cost £35 plus fitting or you could do it yourself in around three hours for the competent home mechanic.
With the engine in good health, you can expect around 30mpg in typical daily driving, which will drop to as low as 18mpg when driving the car hard on the road or track.
For more power, aftermarket exhausts add to the sound but little to the overall horsepower. Freeflow induction kits should be fitted with caution as some mount the inlet very low in the engine bay, which risks scooping up water from deeper puddles and potentially causing the engine to hydraulic. Some cars have had supercharger kits fitted, which can provide up to 300hp.
PHer's view:
"I had my 306 GTI-6 for two years, I was totally sold. However my ownership wasn't without its problems as I had quite issues with a cambelt going 5K before it was due its change - causing a lot of engine damage and an ECU issue that went on for some time and cost quite a bit."
Chris Jones