Re: Plz Help! Changed Coolant, now its hotter than before :(
Coolant actually makes a motor run hotter if the cooling system is sub-standard or has another problem. All to do with the surface contact area of pure water being better than coolant because of molecular heat exchange efficiency, ie the wetness of the stuff. Lots of race cars run a wetting agent instead of coolant for that reason.
So going to new coolant and it runs hotter highlights another problem, perhaps thermostat and/or radiator core.
For a quick fix, drain the coolant into a container for later on and exchange it for pure RO water if you can or tap water and take it for a drive. Guaranteed you will get a big drop in temp, enough to get by, but you will need to track down what the underlying problem is. Doubt it is an airlock.