Hi
A panda that I purchased about 3 weeks ago hadnt been bled properly after a water pump replacement. It took 1.5 litres of coolant to top it up. Before the last one(0.5l) it warmed up nice and quickly Straight to operating temp and it stayed there. After the last top-up it is taking much longer to climb the last section on the guage and the temp fluctuates based on speed( holds just about at town speeds and loosing when cruising at 40 or above or going down a hill. I'm thinking thermostat is opening too early and would like to know if other pandas fluctuate much(one section of the guage). Also is there a reason that it only occurred after the last fill?
The car never showed temp as above the middle of the guage even when low.
Car is a 1.2 59plate
Thanks for your help.

Thermostat needs changing.
With the coolant low it probably just didn't allow the coolant to flow round the system correctly so heat transfer wouldn't be as good.

When the temperature gauge fluctuates regardless of speed, stop quickly and check the coolant content as it is probably low.

When the temperature gauge fluctuates according to speed, its a sign the thermostat is allowing the better airflow at speed to over-cool the engine. You need a new thermostat. If you are careful, you will not need to add much coolant after dong the repair.

DaveMcT said:

You need a new thermostat. If you are careful, you will not need to add much coolant after dong the repair.

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Hi. Is that you suggesting i don't drain the coolant before hand?
thanks for your help.

If the coolant is old you might as well drain it down, fill with clean water and run the engine to flush the system, drain again and fill with new coolant.

If the coolant is new, you will not lose much by carefully taking off the thermostat housing. Top up afterwards, always bleed the system and recheck the level after running the engine.

nikonman said:

the temp fluctuates based on speed( holds just about at town speeds and loosing when cruising at 40 or above or going down a hill.

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https://www.fiatforum.com/panda/465356-common-problem-thermostate.html

The fact you have to keep filling it up also needs looking at ASAP

koalar said:

https://www.fiatforum.com/panda/465356-common-problem-thermostate.html

The fact you have to keep filling it up also needs looking at ASAP

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If the car is using coolant you run a very high risk the head gasket is getting over stressed. You need to find the leak and fix it. If there are no visible leaks it may already be too late. Get coolant checked for hydrocarbons. Even better get cylinder compressions tested.

When the job is done you will probably need new O2 sensor(s) as well. They do not tolerate coolant in the exhaust gas.

Car only needed topping up because it hadn't been bled properly before I brought it. 1.5 litres of bubbles. Coolant level is fine now, and a new thermostat has fixed all issues.

Keep checking coolant levels. 1.5 litres is a heck of a lot to lose to bubbles.