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Dissapearing Coolant

Our Toyota Avolon is loosing coolant fast! My husband noticed the engine heat going up and down and stopped at a gas station to check the coolant. It was completely empty. He filled it up and continued on his way. However, after driving it home less than 6 miles, the coolant was completely empty, no pooling under the car or anything. He filled up the coolant again when he got home, saw that some of the hoses going to the radiator were loose/worn and tried fixing it the best he could. This morning before leaving he checked the coolant level and it was completely empty again! Where is it going?! No pooling, we didn’t run the car over night, nothing! HELP! This car is also getting old, has over 250,000 miles on it and we have our second child on the way. Is it time to say “buh-bye” to it?

I’d recommend NOT driving it again until the leak can be found. If you do, you’ll almost surely ruin the engine (or cause very expensive damage) if you haven’t already. Have it towed to a reputable shop for diagnosis.

The reason you probably haven’t seen a puddle is probably because it’s only leaking when the engine is running, or perhaps because there was no coolant in it to leak. A couple of leak-related conditions occur when the engine is running that aren’r there when the engine is stopped. (1) the fluid heats up and becomes pressurized, usually up to 15+/- psi, and (2) the water pump shaft is spinning, and sometimes seals will leak when the shaft inside them is spinning that won’t leak when the shaft inside them is not.

I agree with everything that mountainbike stated, but I think it is important to add that–depending on how badly and how often the engine overheated–there is potential engine damage including breached head gaskets, scored cylinder walls, and damaged bearings.

If any of the above turns out to exist, then it is not worth repairing a car with 250k miles on it.

Also check the oil dipstick. If coolant is “disappearing” into the oil sump the oil level will appear to be above the “full” line on the dipstick and the oil may have a gray color.

Coolant in the oil will ruin an engine quickly. As advised above, do not start the engine. Have it towed to a shop.

I smell a broken cylinder head.

OP’s car overheats, OP and spouse pour cold replacement coolant into a red-hot (?) engine, the metal cracks like pouring icewater in a glass just out of the dishwasher.

Some people always jump to the worse case scenario. It could be a leaking host that just needs to be replaced or more serious like a water pump. Worse case would be a head gasket. The problem is that a best case can turn into a worse case very quickly. A pressure test should uncover the source.

Is he filling the radiator or just the overflow reservoir? When the system is cold, he needs to fill both, then take it to the nearest recommended mechanic or dealership to find out where the loss is. Then make a decision. The mechanic should be able to show you the leak, if he can’t, go to another and gedt a second opinion.

My guess is he’s re-filling the reservoir, not the radiator itself.
It might have been slowly leaking for a long time.

Each time he fills it there’s still a lot of air in the main system, and with expansion/contraction the reservoir empties into the system to displace the air.
He needs to take off the radiator cap when the system is cold and fill it there first, after fixing the leak.

First, replace the hoses and clamps if tightening doesn’t fix them.
Next I’d suspect the water pump, as mountainbike said.

Ok, took the OP at face value. Empty radiator, followed by fill up, empty again in 6 mi is either a cracked head…or a missing hose.