What is causing a coolant leak in my Ford Focus?
I have Ford Focus 1.0 Ecoboost 2015 which has a coolant leak. I took it to a garage 2 months ago where they suspected a leak through the heater matrix and said to change it will be a lot of work removing the dashboard etc which they can't do and I have to take the car to showroom and the cost of doing it can be around £2000.
They advised me to keep an eye on the coolant and top it up accordingly. My observation is the coolant only leaks if I keep the AC on during driving and see a puddle on my driveway after the car is parked in an hour or so. However this doesn't happen if I drive the car with only the heater on but AC off.
I am not sure if I should take the car to other garage for second opinion and considering the value of the car now if its worth fixing the issue.
Can you please advise how much will it roughly cost to fix such kind of issue and why does it leak only when A/C is on but doesn't leak with heater on?
They advised me to keep an eye on the coolant and top it up accordingly. My observation is the coolant only leaks if I keep the AC on during driving and see a puddle on my driveway after the car is parked in an hour or so. However this doesn't happen if I drive the car with only the heater on but AC off.
I am not sure if I should take the car to other garage for second opinion and considering the value of the car now if its worth fixing the issue.
Can you please advise how much will it roughly cost to fix such kind of issue and why does it leak only when A/C is on but doesn't leak with heater on?
Asked on 9 January 2026 by Santosh Gawde
Answered by
David Ross
Given the circumstances you describe a fault with the heater matrix seems like the most likely cause of the leak, although it could also be down to a failing water pump which would explain why the fault only occurs when the air conditioning is being used. Changing a heater matrix can be a time consuming job due to its location behind the dashboard, so we would advise getting a second opinion from an independent Ford specialist who will be experienced in dealing with these issues and should be able to provide you with an accurate diagnosis and a competitive quote for the work. The replacement part could be less than £100, but the labour could be as much as three or four hours. There is also the possibility that it is just the seals on the heater matrix that have failed, which would be a cheaper repair.
Tags:
faults
coolant leak
Similar questions
I own a 2015 Ford C-Max 1.0-litre EcoBoost. The clutch burnt out on the M25 in horrendous traffic, I was lucky I found a stretch of the hard shoulder without an accident happening. Ford refused to pay...
You have recently given a number of answers on timing belts, e.g. on length of time before fitting a new belt and failures on the Ford Fiesta. I have a Ford Focus with a 1.0-litre turbocharged engine (125PS),...
I have a 2016 Ford Focus and its MoT is due end March. Its only done 3000 miles since its last MoT and service. Should I get it serviced or could I get away with just an MoT this time?
Related models
.jpg?width=115&height=75&rmode=crop)
Relaxed but still enjoyable to drive, well-equipped for the money, a huge choice on the used market.
Elsewhere on 
