When my car is cold, my coolant overflow tank is almost empty. I was wondering if other owners could take a quick look to see if their overflow is almost dry when the car is cold. When my car is cold the coolant it right up at the radiator cap when I remove it and look.

My understanding is that the overflow will only have coolant in there when the radiator heats up and the coolant expands and overflows into the reserve tank.

I'm just wondering if I should add some distilled water or leave it alone.

Thanks

 

It should have not fall past minimum. I always keep mine topped up. Your fluid is probably leaking somewhere. Hose, radiator cap, headgasket...

 

just make sure when it's the coldest you have it (as said above) at minimum. If it falls below that it can take in air (don't want that).

EDIT: And yes, as the engine heats up more coolant will go into the bottle

 

thing to point out

my car needs a top off of a good 1-1/2 every year or so

system appears to not be leaking at all and there is absolutely no coolant in the oil

still bothers the crap out of me

 

might need a headgasket if it doesnt have anything in it when its cold but fills up after you drive it

 

run a compression test, if on of the cylinders is dramatically lower than the other it could be a blown headgasket

 

Yesterday I put on new heater hoses. As I was refilling the radiator I decided to check the pressure cap even though I replaced it 6K ago. Seven PSI slowly sinking to zero. Oh great, I thought, now that I am all dirty, I need to go to the store. Before I went, as the service manual recommends, I gave the cap a washing in tap water. Now, it tested 16 psi.

So, anyway, before I started, the level in the bottle was low. Maybe that was the reason.

I have always had a cooling system pressure tester - I wore out one. And, over the years, except for the new ones, the majority of caps I have checked have not held pressure. It is a cheap part that gets ignored.

 

I poured in some distilled water to the half-way mark on the overflow.

I'm just gonna keep an eye on it to see what's up. Freaking overflow looks crusty on the drop hose and fluid looks kind of milky, but not in the radiator, overflow res only, but that could be cause coolant hasn't gotten hot enough to mix through yet. Water pump was just replaced with the timing belt last month so hopefully it was just air bubbles settling.

Road trippin it into the desert in a few weeks don't want to get into trouble.

 

Mine was looking bad too. I just unbolted the overflow tank and cleaned it out really good when I flushed my coolant.