Recently bought a secondhand Fiat 500 that makes ‘sloshing’ sound behind the dashboard on cold start and hard acceleration. I noticed radiator coolant was a little low (right on the min mark) so topped up to the max line. Later after driving, the coolant had dropped to the min mark again. Thinking maybe the fluid may have driven out some air in the rad, I topped up again to the max mark. After driving the level was back to the min line again and stays there. If it’s a leak why does it not drop below the min line? Really hard to tell if the rad is leaking visually since the roads are so wet recently that the car is permanently dripping wet under the engine anyway. Any ideas? Thanks

Bagofwasps said:

Thinking maybe the fluid may have driven out some air in the rad, I topped up again to the max mark.

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Please tell us you topped it up with coolant, not plain water. Running with less than the recommended concentration of a properly inhibited antifreeze will lead to internal corrosion in both engine and radiator. Apologies if you've done this, but I've seen quite a few wrecked engines as a result of folks doing this.

Bagofwasps said:

Any ideas?

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Get it fixed properly before driving the car again. If you are in any doubt about the quality of the coolant, change it now - who knows what the previous owner may have used to top it up. The 1.2 in particular is prone to localised overheating, with accompanying HG failure, if run low on coolant. It's essential to check the coolant level regularly on these cars. Neither the temperature gauge nor the overheat warning light give you sufficient warning of an impending problem; by the time you notice anything is amiss, the damage is often done.

If you ever notice gurgling noises from the dash area, and/or loss of heat from the heater, stop immediately and check the coolant level. If in an emegency you do have to top up with plain water, add an equal amount of concentrate (or, better, change the coolant) as soon as possible, and in any case within 48 hrs.

This thread is a good example of the kind of thing which can happen if the cooling system is not maintained in good order.

No it's OK I'm using the recommended Paraflu UP. The coolant that was already in there looked an orangey colour so I'm guessing (hoping) it was the original. The gurgling sound has been there for a few months and the coolant has stayed at the same level constantly during this time. It's only now when I topped up the coolant that the level suddenly dropped back to the min mark again.

You often get that when filling a system from empty. It’s the air in it. Take off the cap and remove the bleed screw. Top up until coolant comes out of the bleed screw hole. Put the cap and bleed screw back in and sit in the car and give it some revs with the heater on, this will push the air round and into the filler tank on the rad. Remove the cap slowly every couple of minutes to release the air. Look into the tank and you will see it bubbling where more air is coming out. Keep repeating this until you get regular hot air and the gurgling stops.

Is the bleed screw the little black one at the top left of the rad just next to the rad filler tank?

No this is the bleed screw be careful I snapped the head off on ours and I'm not rough handed

OK so I tried the suggestions - topped up more (Paraflu 50:50 with water) revved engine with heater on (actually took it for a low gear drive around to get it really warmed up) opened the bleed screws and rad tank and then topped up again. Level has stayed up this time and can't hear sloshy noise. Will wait till the engine is cold later and try again but so far, so good! Thanks for everyone's input!

Bagofwasps said:

OK so I tried the suggestions - topped up more (Paraflu 50:50 with water) revved engine with heater on (actually took it for a low gear drive around to get it really warmed up) opened the bleed screws and rad tank and then topped up again. Level has stayed up this time and can't hear sloshy noise. Will wait till the engine is cold later and try again but so far, so good! Thanks for everyone's input!

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You're doing all the right things .


Basically the 500 cooling system is a pig to fill; airlocks are almost inevitable. The bleed in the heater hose is marginally useful, the other one is frankly useless. On a first fill, remove the heater hose bleed completely (but replace before starting the engine or you'll have coolant everywhere). Take care with this as it is rather fragile.

The upside is that the system will self bleed over a few cycles if you keep the reservoir topped up to the MAX mark. Do this each morning; the level should have settled after 3-4 days. If it persists in dropping after this time, you have a problem which will need further investigation.

jrkitching said:

You're doing all the right things .


Basically the 500 cooling system is a pig to fill; airlocks are almost inevitable. The bleed in the heater hose is marginally useful, the other one is frankly useless. On a first fill, remove the heater hose bleed completely (but replace before starting the engine or you'll have coolant everywhere). Take care with this as it is rather fragile.

The upside is that the system will self bleed over a few cycles if you keep the reservoir topped up to the MAX mark. Do this each morning; the level should have settled after 3-4 days. If it persists in dropping after this time, you have a problem which will need further investigation.

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If you follow the way I suggested it will bleed and be ready to go in about 20 minutes.

Looks like its all sorted now. Coolant has stayed level for two days and no more gurgling noise. Thanks everyone for your help!