Hi everyone!
I’m experiencing a strange issue with my 2018 SEAT Leon 5F 1.8 TSI (180 HP, CJSA engine, Xcellence trim), and I’m hoping someone here has experienced something similar.
The symptoms:
Previous repairs:
In May 2026, the water pump and related components in that area were replaced.
I’ve also noticed that the front heat exchanger, visible through the lower bumper grille, has quite a lot of bent fins from stone impacts. However, I’m not sure whether this is related to the problem.
What I’ve found so far:
I’ve read several forum threads describing very similar symptoms. Some owners reported steam without any coolant loss, while others experienced both steam and coolant loss.
Some mentioned leaking hose connections, clamps, valves or the thermostat housing.
I’m planning to inspect the underside of the car and perform a cooling system pressure test to try to locate the leak.
My questions:
I’m experiencing a strange issue with my 2018 SEAT Leon 5F 1.8 TSI (180 HP, CJSA engine, Xcellence trim), and I’m hoping someone here has experienced something similar.
The symptoms:
- After switching off the engine, steam starts rising from the lower area of the radiator/cooling fan assembly.
- The steam usually lasts around 1–2 minutes before disappearing.
- There is a noticeable sweet smell, similar to coolant.
- I’m losing approximately 100 ml of coolant per month.
- The engine has never overheated, and the temperature gauge stays at a steady 90°C.
- It happens in both dry and rainy weather, although the steam seems more noticeable when it’s raining.
- I drive approximately 20 km on the motorway every day.
Previous repairs:
In May 2026, the water pump and related components in that area were replaced.
I’ve also noticed that the front heat exchanger, visible through the lower bumper grille, has quite a lot of bent fins from stone impacts. However, I’m not sure whether this is related to the problem.
What I’ve found so far:
I’ve read several forum threads describing very similar symptoms. Some owners reported steam without any coolant loss, while others experienced both steam and coolant loss.
Some mentioned leaking hose connections, clamps, valves or the thermostat housing.
I’m planning to inspect the underside of the car and perform a cooling system pressure test to try to locate the leak.
My questions:
- Has anyone experienced steam coming specifically from the lower radiator/fan area after shutting off the engine?
- Could a small radiator leak cause these symptoms even if the engine temperature remains normal?
- Are there any common coolant connections, hoses or seals in this area that I should pay particular attention to?
- Could the steam and coolant loss be two separate issues?
