disappearing coolant

[roberttran]

My car is a 99 and has 55k miles on it. I changed and flushed my coolant about 2 months ago. I filled it up to the max mark on the expansion tank with 50/50 Toyota coolant and distilled water. I've noticed that after driving afew times and letting the car cool down the coolant is at the minimum mark. I fill it back up to max thinking maybe there were air bubbles in the system. I drive afew more hundred miles and once the car is cool, its back at the minimum line. If I drive around at the minimum line and wait for it to cool down, the coolant stays at the minimum line and never goes under it.

What could be causing this?

Thanks,
Robert

 

[NMuzj100]

I'd still say bubbles.

Do your oil and tranny fluids look healthy?

 

[roberttran]

I'd still say bubbles.

Do your oil and tranny fluids look healthy?

Oil and tranny fluid are fine the last time I checked them. I'll check them again next them I do an oil change.

No visible leaks or pools of coolant anywhere

 

[ff347]

When you filled it, did you let it run with the rad. cap off and watch the coolant go down as the motor warmed and the thermostat opened? I would say bubbles also.
Scott

 

[Kanab]

Where was the level before you changed the fluid? Maybe the low line is normal for your LC???

 

[Jukelemon]

Um, if you are stating it correctly i.e. 50/50 mix and then distilled water (which should be 50%), you have essentially a 25% coolant/75% water mix. If that is true, then your levels are lowering due to the fact that you are evaporating the water.

Juke

 

[Jim_Chow]

Are there any coolant splash marks in the engine compartment? First, as others have suggested, I'd park the rig on the slope w/ cold engine, remove radiator cap, and burp the system. In my case, I do this everytime, but this last time, I had a problem w/ mysteriously disappearing coolant. It turning out to be a very subtle hose leaking at the clamp. If I drove the car more than 8 miles (hot engine), there was no sign of any leak. Only after I drove it short (1 mi) did I notice it leaking. I tightened the clamp, but it still leaked (about 2 drips/sec).

Turns out, the cooling system, when warming up, is under quite a bit of pressure since the valve in the radiator cap has yet to open, so the warm coolant can't flow into the bottle. Once the engine heated up, the cap valve would open, allowing coolant to flow into the bottle. But before that happened, it would leak, then the engine fan would blow the stuff all over. Took a couple of months to figure this one out, as I normally drive at least 20 mi in the rig, so I'd never see any leaking, just disappearing coolant. After replacing the hose, all is well.

 

[Jukelemon]

Also, as this happened to my 99, there can be a leak at the very rear of the head at the tapped in nipple for the heater intake hose. If you look at the right side of the head in the very rear you might find a large area of dried coolant. If that is the case, let me know.