Why is my coolant reservoir full and the radiator appears to be low on coolant?
That happens when the cooling system is not able to build a vacuum to slurp the coolant from the reservoir when it cools. The usual causes are a bad radiator cap (the outer seal is bad) or a small leak in the cooling system. The drill is to replace the radiator cap first (with one from the dealer - aftermarket caps are not to be trusted) and then to look for a small leak if the problem persists. Because the level in the radiator was so low I suspect there is a leak, but rule out the cap first.
Why is my coolant overflow at the cap after driving?
Any such Leaks is an Indication of a problem. There are two caps Cooling system not sure which one you are talking about 1. Reservoir Fill cap or 2 Radiator Cap.Liquid expands when heated . So the coolant takes up more space when Heated. If the cooling System in a car was total closed the pressure from the expanding coolant would likely break something. Keep the Coolant under Some pressure however Increases its boiling point allowing an engine to operate at more efficient higher temperature and still not have coolant boil off. This is the purpose of the radiator cap that operates as pressure regulating valve. The valve in the cap opens allow Coolant to Flow through the Hose just under the cap back into the Coolant reservoir. When the engine shuts of The coolant Cools creating a vacuum sucking the coolant back out of the reservoir and into the radiator. There are marks indicating Full Cold and Full Hot on the reservoir. If the coolant is cold and the reservoir filled to the hot full mark when the coolant expands it could come out the top of the reservoir coating all the electrical component of the engine in water/coolant, Which is not good, so all reservoirs have a molded in over full pipe that directs excess coolant out of the reservoir to below the engine bay .If coolant is coming out of the Reservoir fill cap then the Overflow piping is plugged. If coolant is coming from the radiator cap then the cap is either defective or not put on properly . One caveat a leak/crack or missing hose from radiator to reservoir /expansion tank can make it seem like the radiator cap is leaking when it is not.
Coolant light on but coolant level is fine.?
Hi guys, I currently drive a 92 Mercedes Benz 400E model and I currently have an issue with my vehicle. When I go back home while driving from somewhere, my low coolant light is on. The first time when I saw it, my coolant light was low and I filled it up with some coolant that is suitable for my car. Later on, in the future, it did not fix the issue at all for the coolant light and I believe there is something wrong with the sensor. Even though my light is on, I believe it does not really affect my performance of the car; it seems to run fine without any problems. Most of the time, I do not know why my coolant light is not very bright, it is very low dimmed. I believe that the sensor would be the problem of why my coolant light keeps going on and off. If the sensor is the problem, how much would it cost for the part and labor (how long would it take to fix)? Do I need to fix it ASAP? Even though my light turns on occasionally and my coolant level is fine. It would not affect my performance of my car right like it will not break down right?
Do you have to wait until your car cools down before you put coolant in your car?
If you havw a coolant overflow tank / bottle, go ahead and pour the coolant (properly diluted) into it. Never try to put coolant into a radiator while the engine is still hot / warm. The coolant becomes pressurized to raise its boiling point; Loosening the radiator cap can expose you to a burst of scalding water. Wait till everything is cool, and then loosen the cap half way to release any remaining pressure, and, only then, open it all the way.
What is the purpose of the coolant overflow plastic tank? Does it have to have coolant in it?
1 is fact that the cooling system in modern cars is pressureized! This is because water under pressure boils at a higher temperarture,- with 50/50 antifreeze-water mix it is a little over 235 degrees (as opposed at 212) Your system has a pressure cap on it designed to release pressure at a certian pre-determined pressure (generally around 12-18 psi)... Water expands when it gets hot, -- so some runs back to reserve bottle where it is captured and saved! The entry from radiator is near the bottom of the bottle -- when the engine cools off, the water "shrinks in volume", - so water is pulled back from the bottle to replentish level inside radiator! This is designed to assure that the radiator remains "topped off" all the time!