Coolant Question

[packetstormin]

Back in May I had my TB and water pump service done along with replacement of all the radiator hoses. I also had the cooling system flushed and converted over to Toyota red. Now I am located here in AZ and we had an exceptionally brutal summer this year. So I checked my coolant level and it was at the min line. Took two cups of Toyota red and two cups of distilled water to get it back up to the full line. So apparently the cooling system is a closed system and thus should not evaporate coolant. I can find no leaks. I am having a blackstone oil analysis done to look at how my oil is wearing so that should tell me if there is any coolant in the oil. I am skeptical of it being the head gaskets because the truck runs well. So any others thoughts about what is happening to my coolant?

 

[OregonLC]

It's a closed system, but not necessarily 100% vapor tight. There are a lot of hose fittings that can allow a tiny bit of vapor to get by. Over time even a tiny loss rate adds up. I wouldn't think your loss rate is alarming, especially in AZ.

 

[wildsmith]

Something I've had trouble with is the radiator cap opening at too low a pressure and sending too much fluid to the expansion tank to the point it overflows a little. It's not noticeable at the time because you tend to be moving and what leaks is hot so it dries very quickly. Replacing the radiator cap was the fix for mine.

 

[packetstormin]

Okay at this point I wont worry about it to much I guess. Though I will buy a new rad cap just to be on the safe side because it is the original 11 year old cap.

 

[2001LC]

When at operating temp check and fill to full line. If filled when cold, fill to low line. Excess will blow out of the systems when heat expands coolant in the systems.

 

[MoJ]

So I checked my coolant level and it was at the min line.

Did you check it when the engine was cold? Have you checked it before when the engine was cold? If the engine was cold there's nothing at all wrong with the coolant being at the min. The min/max points are for the coolant to expand and contract with operating temp. If you add too much coolant while it's cold you'll likely have it overflow when hot. All else equal it should eventually stabilize.

 

[packetstormin]

It was hot when I checked it.