Fuel economy and exhausts

 The Clio is quite simply very thrifty. Being small and lightweight clearly helps. A full tank shall get 400+ miles which is about 50 to the gallon. It does however pay to have perfectly serviced spark plugs (mind the gap!) and leak-less exhaust. The original exhaust provides a very acceptable level of cabin noise and in fifth gear you can get up hills despite the 1.2 L engine capacity.

A recent MOT failure was the exhaust and the emissions:

Repair immediately (major defects):

• Exhaust Lambda reading after 2nd fast idle outside specified limits

A replacement centre section pipe solved this. It is worth appreciating how the momentum of exhaust gases in a long tube helps suck residual fumes out of the engine at bottom-dead-centre so that the next burn is that little bit cleaner, and with luck, a slight vacuum awaits the next charge.  Changing the engine oil does not guarantee an improvement of emissions but healthy spark plugs help plus you get extra power. Every little helps with a small engine! Timing is of course automatic on fuel injection engines and is also vital. Miss-fires for any reason result in unburnt petrol entering the catalytic converter, which can damage it. Fortunately these are about £40 because the old design of car does not require ludicrously priced components!

My last word on the exhaust system is disappointment there are few suspending points. The pipe is constantly in torsion about the L-section and a bit of corrosion will cause it to twist itself apart, but not much can be done, save adding a extra suspension point.

Any engine with a fabric cam shaft drive belt is liable to destroy its self when the belt wears out through lack of servicing. A loud popping in the exhaust may be the first warning sign you get if the teeth have jumped and you are not a aggressive driver. I believe I heard this happen yesterday. An old gentleman was driving his Fiat which had a loud ticking noise from the pipe shortly before stalling on a roundabout. Happily we are in The Midlands and people are friendly. 5 bystanders got there before me to push his car, and luckily a repair garage was just 150 yards away!