Temperature fluctuation

[MQ2596]

Hey everyone. I have a 2012 C250 1.8 Petrol with around 55k miles on the clock. I’ve had the car for around 2 months now and the temperature gauge has consistently indicated around 90 degrees once warmed up. On two occasions I’ve noticed that the reading drops to around 80-85, before rising back up to 90 and staying there. Is it likely the thermostat is about to go kaput? I’ve checked coolant levels and there’s no issues there. The car is booked in with a Merc specialist for them to investigate possible trapped air in the system (bubbling noise heard through dash), could air in the system be causing these fluctuations or is the thermostat on its way out? Thanks in advance!

 

[markjay]

That's normal. The thermostatic switch kicks-in activating the radiator fan that cools the engine down.

If the car gets to 80⁰ quickly from cold (~5 minutes), and then stays at 80⁰+ throughout the journey, then the thermostat is fine.

 

[MQ2596]

That's normal. The thermostatic switch kicks-in activating the radiator fan that cools the engine down.

If the car gets to 80⁰ quickly from cold (~5 minutes), and then stays at 80⁰+ throughout the journey, then the thermostat is fine.

Ah I see, it’s the first time I’ve seen it happening so thought something might be wrong. Thanks for the info! I’ll keep an eye it on over the next few days