Hey everyone,

So I started my car today and after some driving I noticed that when I am at a red light stopped for a while my engine coolant temp goes all the way to the red, but as soon as I start driving the needle drops almost instantly to normal temp. I think I may have lost too much coolant through a small leak in my overflow reservoir, seeing as there is some coolant on the header heat shield. Should I fill top it off with some water temporarily? also is my diagnosis correct?

thanks for the help!

 

Yes fix the leaky coolant tank and top up the coolant, then make sure the fan is coming on.

It's a good idea to use a scangauge to monitor the temp and ensure the thermostat, and fans are working. The temp gauge in the dash is just an idiot light and will stay at 1/2 till it reaches 240 deg then move so it will be too late at that time and you can damage the engine.