Hi,
I changed the coolant in my Renault Megane the other day. I ran the engine at 2000 RPM for 5 mins with the expansion tank cap off then ran it for about 30 with the cap on. During both periods it made a sloshing sound which appeared to come from the passenger side as the revs increases. The problem decreases after the engine has been running for a while and occurs only at progressively higher revs as the engine has been on for longer.
Having idled the engine the coolant level went down so I topped it up. I'm guessing the sound is that of air bubbles in the system.
It appears to have got a little better by the next day when I drove the car (topping off the coolant a little before driving). Is this a problem that is likely to get better with time or is there anything I need to do? (e.g. idle it for 20 mins with the expansion tank cap removed)?
Cheers,
Rob