What are the signs of a failing thermostat valve in an older Suzuki Bolan?

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What are the signs of a failing thermostat valve in an older Suzuki Bolan?

My Suzuki Bolan is a 2011 model, and it’s been having inconsistent temperature readings—sometimes it stays too cold, and other times the needle shoots up. I suspect the thermostat valve is failing. What are the most common symptoms of a bad thermostat in an older Bolan, and how urgently should it be replaced?

Gari Specialist asked on 10 Apr 2025 12:03:19 pm

1 Answer

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Gari Master - on 10 Apr 2025 12:17:54 pm

In older Suzuki Bolan vans especially 2010–2015 models, thermostat valves can wear out due to corrosion, scaling from tap water, o r just age.

Common symptoms of a bad o r failing thermostat:

Fluctuating temperature gauge goes hot then s suddenly.

Heater doesn’t work well.

Engine stays cold for too long o r overheats suddenly.

Poor mileage and sluggish performance in winter.

Coolant leaks o r pressure build-up in radiator.

When to replace it:
As soon as you notice inconsistent engine temperature o r poor heater performance, get the thermostat checked. It’s a small and affordable part but can save your engine from major damage.

Pro Tip Pakistan-specific:

Always use coolant instead of plain water to avoid rust and scale.

Replace thermostat every 3–4 years as part of preventive maintenance.