Recently i changed my radiator because it had a leak. I drained and filled new coolant and bled the air by burping it as much as I can. I pressure tested the coolant system and it held good pressure for over an hour. I filled the coolant in the overflow tank to about half way mark then after about 500 miles of driving over a span of couple of weeks, i checked the coolant level in the overflow bottle and it had dropped by few centimeters maybe about 2 or 3cm but not right at the low point. So I then topped up to the top again and have since done over 1500 miles (not km) and the coolant level seems to have mainted well. probably dropped about under 1 cm but still at the top end of the full mark. Is this normal? also when cars running for a long time after a long journey, ocassionally i can smell hot coolant kind of smell but no visible leaks mainly that smell is noticable if i'm idling the car and engine is hot after a long drive as the fan kicks in it blows a whiff of that smell.

 

Sounds like normal, you are good.

 

If you're still smelling coolant. There could be some residue sitting around. On a cooled down engine hose down the area with water. Also you can scrub the bottom engine under cover. It has some padding that can absorb some spilt coolant. Remember to avoid hosing down on the electrical connectors, and let it air dry to some degree.

 

It should not be difficult to get air out of the system on these engines, and get the system full of coolant. I hope that everyone understands that after "dumping" all or most of the coolant due to a full coolant drain and refill or a rad replacement for example that you HAVE TO fill the cooling system through the rad fill port (where the rad pressure cap resides) right to the top allowing time for the coolant to "backflow" through the "hot" hose into the engine heads and block. The coolant will not get past the closed thermostat via the "cold" hose into the engine block/heads. Keep slowly filling the rad to the top with the bleed screw open until coolant comes out the bleed screw and then close the bleed screw. Install the rad cap. You CANNOT fill the system through the overflow tank! It's only used to top off the system and that's with a "tight" system only. After the basic fill run the engine at idle only watching the coolant temp gauge for an increase in temp.There should be an increase in coolant temp fairly quickly. If not check the level in the rad fill port and top up as required (whenever you remove the cap do it slowly if the coolant may be hot). If the rad level is still at the top (and I mean right at the top) and there are no leaks then fill up the expansion tank to the "min" level. Go drive the car and recheck the expansion tank level afterwards (engine shutdown).