Parts for your 2010 Suzuki Splash-Thermostat

2010 Suzuki Splash Thermostat: what it does and when to replace it

Yes, the 2010 Suzuki Splash is fitted with a conventional engine coolant thermostat. This is confirmed by Suzuki’s factory Workshop Manual for the Splash/Ritz (Cooling System section) and the Suzuki Electronic Parts Catalogue, both of which list a wax‑pellet thermostat assembly in the water inlet housing for the K10B 1.0‑litre, K12B 1.2‑litre and D13A 1.3 diesel engines. The Opel/Vauxhall Agila B (platform twin) shows the same arrangement in its service literature.

The thermostat’s job is simple but vital: it regulates coolant flow so the engine warms up quickly and then stays at its designed operating temperature. Cold starts get a faster warm‑up for smoother running and lower emissions, and once warm, the thermostat meters flow to the radiator to stop temperature wandering on the open road or in summer traffic.

For a 2010 Splash, the thermostat isn’t typically a scheduled replacement item, but after a decade or more it’s common preventative maintenance—especially if there are temperature irregularities. When servicing, owners often pair a thermostat change with a coolant flush so the system starts fresh with a new seal/O‑ring.

• Common clues it’s due: cabin heater stays tepid, gauge sits lower than normal on the motorway, takes ages to warm up (stuck open), or conversely, overheating and hard upper hoses (stuck closed). A P0128 code on OBD scan is another giveaway.
• Good practice at replacement: always fit a new gasket/O‑ring, note the jiggle valve orientation (usually up), and bleed air thoroughly after refilling.

On the Splash’s K‑series petrol engines the thermostat lives in the water inlet housing where the lower radiator hose meets the engine. Access varies, but a cool engine, drained coolant, and clean mating surfaces are the basics. After refilling, run the engine with the heater on hot to purge air, top up the reservoir to the mark, and check for leaks once it’s cooled again.

Coolant choice matters. Use a quality ethylene‑glycol, long‑life coolant that meets Suzuki specifications for the Splash in Australia and New Zealand. Mixing types is a no‑go, if uncertain, fully flush before switching. With the right thermostat and fresh coolant, the Splash holds temperature nicely, protects the alloy head, and keeps fuel economy and drivability on song.

• Where is the thermostat on a 2010 Suzuki Splash?
  It’s housed in the water inlet where the lower radiator hose connects to the engine. On the K10B/K12B petrols it’s at the front of the engine bay, secured by a small alloy housing with 2–3 bolts. Always work on a cold engine and expect some coolant loss when opening the housing.
• What are the signs the thermostat needs replacing on a Splash?
  Slow warm‑up, a temperature gauge that runs cool at highway speeds, weak cabin heat, or a P0128 fault suggest a thermostat stuck open. Overheating or pressure spikes can indicate it’s stuck closed. Visual leaks around the housing or a perished O‑ring are also prompts to renew it.
• What coolant should be used after changing the thermostat?
  A quality, long‑life ethylene‑glycol coolant that meets Suzuki’s spec for the Splash. Many models use blue long‑life coolant, the key is matching the required chemistry and not mixing types. If switching brands or colours, do a complete flush first.