Ford Fiesta Saloon 1.2 zeetec petrol reg 2000 - Will a small exhaust hole affect fuel consumption

Honest John Back Room » Technical matters
View Threaded
Mon 23 Mar 2015 11:32
Ford Fiesta Saloon 1.2 zeetec petrol reg 2000 - Will a small exhaust hole affect fuel consumption - KenC

I am seeking opinions please,

a relative has a Ford Fiesta reg 2000, 1.25 zeetec petrol engine, over several months the fuel consumption has crept up or increased. I know short journeys and cold weather ruin fuel consumption but over the last few tankfulls it has been as low as 24 mpg average,previous winters were 28/30 mpg.

I have checked the obvious eg binding brakes, all the wheels turn fairly easily when jacked up, the tyre pressures are as per the handbook, the airfilter is not clogged or dirty.

I have noticed that the rear exhaust silencer box is fairly rusty where the pipe from the centre box joins the rear box. There is no obvious noise and the MOT tester has passed the vehicle BUT every time the car is parked on a slope with the rear lower most I notice an amount of moisture dripping from the body of the rear silencer box, so there must be some sort of leak for water to escape

My question is

" Could a small leak like this cause an increase in fuel consumption "

thank you all

Reply | Report as offensive | Link
Mon 23 Mar 2015 12:45
Ford Fiesta Saloon 1.2 zeetec petrol reg 2000 - Will a small exhaust hole affect fuel consumption - RobJP

In short, yes. It is possible for a damaged exhaust to make fuel economy worse. Exhaust lengths are carefully designed, the length of an exhaust makes a huge difference to back-pressure, and whether the exhaust 'breathes' fully. A hole in the exhaust messes with all that.

Having said that, I'd be surprised if it made as much difference as you're describing. I'd suggest checking spark plugs, whether the oil and oil filter have been changed (a well lubricated engine will run more efficiently), and possibly taking it out for a drive yourself (if insured) to make sure everything feels right.

Reply | Report as offensive | Link

Looking for a garage you can trust? Honest John's Good Garage Guide has thousands of reader recommended garages, plus how-to guides and tips on servicing.

The Good Garage Guide

Real MPG enables you to register the fuel economy you are actually getting against your make and model of car, its engine and type of transmission.

Every time you enter an average consumption figure against your car, the overall average automatically adjusts to reflect it.

Real MPG