Ford 1.0 EcoBoost (Fox)Thermostat and cooling systemIntercooler and turbo hoses
Coolant leaks and overheating from the turbo hose on the 1.0 EcoBoost
Why this rating?
Critical severity: It can destroy the engine or gearbox, or affects safety.
Frequency occasional: The best-documented case we have been able to verify is a 2013 Ford C-MAX in Spain whose turbo hose burst without prior warning and ended up seizing the engine; the reliability press describes coolant leaks and cylinder head gasket failures in early units of the 1.0 EcoBoost, but we have not found data to support saying it is as widespread a problem as the belts running in oil.[1][2]
Symptoms
- The coolant reservoir level drops without obvious stains under the car.[1]Coolant level drops: other faults that cause it · Garage soon
- The engine temperature can rise sharply when the circuit runs out of coolant.[2]Overheating: other faults that cause it · As soon as possible
- In the case documented in Spain, the car gave no prior warning: only the Start-Stop button locked just before the engine seized.[1]
Why it happens
The hose connecting the cooling circuit to the turbo withstands high temperatures and pressures, and can crack or break over the years.[1]
The British reliability press describes leaks from the water pump or the hoses themselves as a common source of overheating in the first units of this engine.[2]
If it is not repaired: Without coolant, the engine can overheat and damage the cylinder head gasket or seize completely; in the documented Spanish case, the official dealer quoted around €7,000 to replace the whole engine, although this is a single case, not a market average.[1]
Affected cars and years
The cases we have been able to document are early units of the Fox (2012-2018); we have no data confirming whether the problem continues in the cylinder-deactivation generation or in the mild-hybrid version.[1][2]
| Version | Years | Codes |
|---|---|---|
| 1.0 EcoBoost 100/125 (Fox, 2012-2017) | 2012–2017 | SFJASFJBSFJCSFJD |
Models fitted with the affected versions
Ford
- Ford Fiesta VII2013–2017
- Ford Focus III2012–2018
- Ford C-Max II2013–2019
- Ford B-Max2012–2017
- Ford EcoSport2014–2022
- Ford Mondeo V2015–2018
- Ford Transit Couriersince 2014
- Ford Tourneo Couriersince 2014
- Ford Transit Connect2013–2019
How much it costs to repair
Includes: Complete engine replacement when overheating from lack of coolant has damaged it beyond partial repair.[1]
There is no reliable market quote for this repair in Spain. As an isolated reference, in the case documented on opinautos.com the official dealer quoted around €7,000 to replace the whole engine, but it is a single case and not a representative average. If the leak is detected in time, replacing just the hose is much cheaper, although we have not found a published price for that minor repair.
Prices in Spain, including VAT. A workshop hour costs on average €38–66 at independent garages and €77–134 at dealerships in Spain, depending on the region and the brand. How we calculate costs
How to check for it before buying a used car
- Start the engine from cold and check the coolant level in the expansion tank; repeat the check after a long test drive.
- Visually inspect the accessible turbo hoses for cracks, bulges or crystallised coolant residue.[1]
- Ask whether the car has ever had a temperature warning or a hose replacement, and ask for the invoice.
Parts needed
The part or kit that fixes this fault, according to the sources.
Turbo coolant hose[1]
It connects the cooling circuit to the turbo; if it breaks, the system empties and the engine can overheat.
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How to prevent it
- Check the coolant level when cold on a regular basis, especially before long trips.
- At any temperature rise, however brief, stop the engine and check the level before driving on.[2]
Recalls, campaigns and claims
As of 26 September 2026, we have no record of recalls, campaigns or extended manufacturer warranties for this fault. Check with an official dealer using the chassis (VIN) number: they will tell you whether the car has any outstanding campaign.
What owners say
Frequently asked questions
Has the 1.0 EcoBoost had a recall for fire risk?
Ford's best-known recall for fire risk due to overheating and cylinder head cracks, covering more than 200,000 vehicles, concerns the 1.6 EcoBoost engine, which is larger and mechanically different, not the 1.0 EcoBoost covered on this page.[3]
Why is my 1.0 EcoBoost losing coolant with no stains under the car?
It may be due to an internal leak or a hose that drips when hot and dries when cold, especially around the turbo. A pressure test of the circuit at a garage is advisable.[2]
Can I keep driving if the temperature rises for a moment and then drops?
It is not advisable. Even if the warning light goes out, each overheating episode can damage the cylinder head gasket; stop the engine as soon as it is safe and check the coolant level.[2]
What can you do now?
We will put you in touch with a partner only if you authorise it in the form.
Other 1.0 EcoBoost faults
- Critical severityFrequency: CommonTimingDegradation of the timing belt running in oilYes: the 1.0 EcoBoost's timing belt runs in oil and can degrade over the years, shedding bits of rubber that block the oil pump and seize the engine without warning. The NHTSA is investigating the case in the United States and Ford has shortened the recommended replacement interval.Repair (garage): €800–€1,200
- Critical severityFrequency: CommonLubricationOil pump belt and tensioner failureYes. In addition to the timing belt, the 1.0 EcoBoost has a second belt, also running in oil, that drives the oil pump. If the tensioner breaks, the belt loses teeth and can cut off oil pressure; in the US Ford has recalled more than 100,000 Ford Focus and EcoSport vehicles for this reason.
- Medium severityFrequency: OccasionalIgnitionMisfires and engine warning light caused by the wiring harnessFord documented in a technical service bulletin that the engine wiring harness can rub against the exhaust heat shield on the 2018-2019 automatic EcoSport, which turns on the engine warning light with misfire fault codes. Spark plugs and coils are also common wear items on this turbocharged three-cylinder.
More faults with the thermostat and cooling system on other engines and cars
- High severityFrequency: CommonM50 and M52Cooling system failure (expansion tank, thermostat, pump and radiator)The most cited weak point of the M52: the expansion tank, the thermostat housing, the pump impeller and the radiator tanks are plastic and crack with age. If coolant is lost and the engine overheats, the cylinder head can be damaged.Appears at around 97,000 km
- High severityFrequency: CommonBMW M54Thermostat and water pump failureThe M54's thermostat, housing and water pump contain plastics that become brittle and fail. If left unattended, overheating can warp the aluminium cylinder head. It is advisable to replace them together.Appears at around 129,000 km
- High severityFrequency: CommonBMW M54Cracked expansion tank and coolant leakThe plastic expansion tank degrades over the years and eventually cracks. It is cheap compared with the cost of overheating an M52/M54, and age matters more than mileage.
- High severityFrequency: CommonPorsche V8 and V6 (Cayenne and Panamera)Cracked plastic coolant pipes on the Cayenne V8The first Cayenne V8s (the 4.5) have plastic coolant pipes under the intake manifold that crack with age and cause coolant loss; Porsche switched to aluminium around 2006-2007. A Canadian workshop says it also affects the later 4.8.
- High severityFrequency: Common1.4/1.6 VTiFragile water pump (and expansion tank or heat exchanger, depending on displacement)Yes: fiches-auto.fr describes a fragile water pump in both the 1.4 VTi (with an expansion tank prone to leaks) and the 1.6 VTi (with the heat exchanger), a cooling problem that the turbocharged 1.6 THP inherits from this naturally aspirated version.
- High severityFrequency: Common1.6 THPFragile water pump and heat exchangerYes: both the naturally aspirated 1.6 VTi and the turbo 1.6 THP share, according to fiches-auto.fr, a water pump and a heat exchanger described as fragile; in the most serious cases, the resulting overheating has gone as far as damaging the cylinder head.
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Sources
Every fact on this page links to its source. If you find an error, let us know.
- Gripa el motor por problema en el manguito se queda sin refrigeranteOpinautos · Owners' forum · consulted 26 September 2026 · in Spanish
- Ford EcoBoost engines: reliability, problems and should you buy one?Carbuyer · Motoring press · consulted 26 September 2026
- The Largest Ford EcoBoost Recalls In 15 Years Of ProductionCarBuzz · Motoring press · consulted 26 September 2026