I did the conv. last night on my wifes '06 Mazda5.I noticed about a gallon of anti-freeze was lost from the part that bolts to the oil filter housing.I filled the tank back up with anti-freeze thinking that would replace the lost fluid,it didn't.My wife told me today that she had no heat this morning.

How do I replace the lost coolant?

 

It sounds like you have an air bubble in the system, some cars have an air bleed on the highest point in the cooling system but most dont, you just have to keep running it till the bubble clears out or unhook a heater hose until you get coolant out of it. Running it can take some time to clear the bubble, you can try parking the car on a steep hill with the nose facing up, that might help to move the bubble. Keep an eye on the expansion tank for low coolant, if it drops all of a sudden that was your bubble leaving.

 

Pull the cap turn the heater on full blast on hot and run it with a raised rpm in park till u feel the hot air from the vents. When it gets hot let off the accelerator pedal and let it idle it will probable go cold again so do it again then top it off and do a hot lap around the block making sure u get the car high in the rpms. (Install cap before driving)

 

It must have been a bubble cause the heat is working now.

The wife was freaking out.

Thanks.