Engine coolant is what I'm assuming you are talking about. Engine coolant is a mix of water and etholyn glycol (antifreeze). It pulls heat away from your engine block that builds up from the friction of moving parts. The coolant mix allows the coolant to get cold to a point and not freeze because of the etholyn glycol. It is also not good to put straight antifreeze into your engine because antifreeze does not have as much cooling potential as water antifreeze mix. Also if you have just antifreeze in your engine the antifreeze will boil at a much lower temperature than a mix of aproxamalty 50/50.
Any brand coolant will work.
when the engine is running and coolant will become hot to its operating temperature,the cooling system is under pressure,coolant will overflow and goes to coolant reservoir.when the engine goes cold coolant will go back to the rediator.
Yes. The coolant carries the engine heat to the heater core. Without coolant the heater core does not get warm.
I would check the coolant level first. When the coolant drops below a certain point,Warm coolant that makes the heater work is no longer present and all you get is cold air. If this doesn't work, I'd try a "hotter" thermostat.
If a coolant leak were caused by brake work, I'd never have that person work on my brakes - ever. Just the brakes, I would think it highly unlikely that it would result in a coolant leak. If they were replacing the master cylinder, then I could see a possibility of someone inadvertently causing a coolant leak, but that would still even be a stretch.
The heater is dependent on the coolant flowing through the heater core. If the coolant is low then there will not be any heat.
Regular bike coolant will work just fine. That is what I use.
Standard green Ethelyn Glycol, or any type of Global coolant will work. always be sure your coolant mixture is 50/50, 50% water and 50% coolant
If it is green then any ethylene glycol or universal coolant will work if it is red/pink/orange then use a universal coolant, the mopar HOAT coolant or Zerex G-05 coolant.
water pump
Check the level in the coolant reservoir. There is a line "wall" in the jug. The coolant level should be just above that line. If it is then check if your reverse lights work. They are on the same fuse. If they work, you probabaly need a reservoir as the level switch is faulty
The coolant fan may have a blown fuse. The electric motor, on the coolant fan may be not working. The ground wire on the cooling fan may be corroded or loose.