Parts for your 2009 Suzuki Splash-Thermostat housing

2009 Suzuki Splash thermostat housing — what it does and how to look after it

Yes, the 2009 Suzuki Splash definitely uses a thermostat housing. Suzuki’s Electronic Parts Catalogue for the Splash (RB, 2008–2014) lists a dedicated thermostat case/water outlet across the K10B 1.0‑litre, K12B 1.2‑litre, and 1.3 DDiS diesel engines. The factory workshop manual’s Cooling System section also details removal and refit of the thermostat at the water outlet on the cylinder head, and major aftermarket catalogues (Gates, Motorad, Vernet) supply complete housings for these engines. So it’s a fitted, serviceable part on this model.

The thermostat housing on a 2009 Splash does a few important jobs. It physically holds the thermostat that regulates coolant flow, helps the engine warm up quickly, and keeps operating temps steady once it’s on the move. It’s also the junction for the upper radiator hose, often carries the coolant temperature sensor, and provides a sealing face to keep pressure and coolant in. When it’s healthy, owners get fast warm‑ups, stable heater performance, and no dramas with overheating or fuel use.

Because most Splash housings are moulded plastic, age and heat cycles can make them brittle. Common signs it’s time to sort it include a coolant weep at the housing seam, crusty white staining, a slow warm‑up (stuck‑open thermostat), or creeping temps in traffic (stuck‑closed thermostat). If any of that pops up, it’s worth inspecting the housing and thermostat together.

Good servicing practice on a Splash is straightforward:

• When changing the thermostat, check the housing for warping, hairline cracks, and sensor port condition. If it’s tired, replace the complete assembly rather than just the stat.
• Always fit a new O‑ring/gasket. Lightly wet the seal with coolant, don’t slather sealant unless the service manual specifically calls for it.
• Refill with Suzuki‑spec long‑life coolant (or equivalent), bleed air at the highest point/bleed screw if fitted, run the heater, and verify fan cut‑in.
• Recheck the coolant level and for leaks after a short drive. A quick look at hose clamps and the temp sensor seal is cheap insurance.

Owners in Australia and New Zealand will often be fine replacing just the thermostat if the housing plastics are still in good nick. But once there’s any distortion or UV/heat ageing, swapping the complete housing saves future grief. Stick to the owner’s schedule for coolant changes, keep an eye out for discolouration around the housing, and the Splash’s cooling system will stay sweet as for many more kilometres.

Where is the thermostat housing on a 2009 Splash?

It’s bolted to the cylinder head at the end of the upper radiator hose. On K‑series petrol engines it’s right where that top hose meets the engine, and usually carries the coolant temp sensor.

Can the thermostat be replaced without changing the housing?

Yes—if the housing isn’t cracked or warped. Given the plastic ages with heat, many techs replace the housing and thermostat together once the original shows any brittleness or leakage.

What coolant should be used after housing or thermostat work?

Use Suzuki‑approved long‑life coolant (ethylene glycol OAT) or an equivalent that meets the same spec. Mix and top up as directed in the owner’s manual and bleed the system properly to avoid air locks.