Car Mechanics (UK)

Coolant loss

- Bar­tosz Boy­a­zont Fiesta · Ford Motor Company · Iceland · Belgium · Belarus · Austria · Fiesta 1

My friend’s 2003 Ford Fi­esta 1.4, petrol man­ual has gone through one litre of coolant over a pe­riod of about two months. I had a good look underneath the car and around the en­gine and I can­not see any ob­vi­ous leaks and the en­gine is sur­pris­ingly dry for its age and 110,000 miles. Since get­ting the car, it has been trou­ble-free apart from a broken win­dow reg­u­la­tor. The air­con blows hot and cold air and doesn’t over­heat.

What should be my next step in try­ing to iden­tify the cause of coolant loss? I won­dered if it might have some­thing to do with the head gas­ket and, if so, how could I check that? I know there are some tester kits avail­able on ebay, but are they re­li­able?

I am also plan­ning to ser­vice the Fi­esta and have al­ready started soak­ing the spark plugs in pen­e­trat­ing fluid as they ap­pear to have not been touched for a long time and look rusted to the en­gine. None of them would move when I tried to undo them to see how they look. Have you ad­vice on how to re­move them safely?

Fi­nally, does this man­ual Fi­esta have level and drain plugs in the gear­box, so the trans­mis­sion fluid can be changed? I could not see any ob­vi­ous ones while un­der the car.

Start­ing with the coolant loss, check­ing in­side the ve­hi­cle for any leaks from the heater ma­trix would be the next step. You may not nec­es­sar­ily have pud­dles form­ing in the footwell, as the coolant might evap­o­rate as it leaks, but there should be signs of the leak in the form of stains around the ma­trix or the lower vents. It would also be worth check­ing the ther­mo­stat hous­ing for any stain­ing, which might in­di­cate a slow release of coolant from the base of the ra­di­a­tor. If one litre is es­cap­ing in two months, it could well be evap­o­rat­ing as quickly as it leaks out, which would explain why no drips are present un­der the ve­hi­cle. An­other po­ten­tial point of the leak is from the water pump. This might be hid­den from view as it is tucked back be­hind the cam­belt cover, and again the coolant may be evap­o­rat­ing be­fore it pools on the floor.

I haven’t per­son­ally used any of the kits avail­able on ebay, but the prin­ci­ple is very sim­ple and they should work ef­fec­tively. Most of them work by using the liq­uid in a ves­sel in the coolant filler neck. The ves­sel seals off the sys­tem, en­sur­ing that any es­cap­ing gas is vented through the ves­sel. By plac­ing a chem­i­cal in the ves­sel, which is sen­si­tive to ex­haust gases, the liq­uid will change colour if gases are in the sys­tem. This will be an in­di­ca­tion of ei­ther a leak­ing head gas­ket or a crack in the cylin­der­head. In the work­shop, we use an ex­haust gas anal­yser placed just above the coolant header tank to de­tect the pres­ence of any gases. Be­fore do­ing this test, though, we use a pres­sure tester to put the cool­ing sys­tem un­der pres­sure, pos­si­bly ex­pos­ing any leaks.

The spark plugs can be very trou­ble­some to re­move and pre-soak­ing them is the best step. I usu­ally try to re­move them after the en­gine has been warmed up and is just start­ing to cool. This means that a small amount of ex­pan­sion and con­trac­tion has taken place, giv­ing the best pos­si­ble chance of suc­cess.

The filler and level plug is at the front of the gear­box, just above the gearchange mech­a­nism, hid­den be­hind a plas­tic shield protecting the mech­a­nism. The gear­box does not have a drain plug be­cause Ford claims it’s filled for life.

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