RAV4 Coolant Recovery Problem

Old 08-10-07, 11:32 AM
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RAV4 Coolant Recovery Problem

I have a Toyota RAV4, 1998, 4WD, with the 2.0 liter 4 cyl and 4 speed automatic ECT transmission.

We bought the vehicle used with about 90K miles.

The problem is the coolant recovery cycle does not seem to work properly.

The recovery tank will take on the coolant from the engine/radiator when hot but the coolant is not sucked back into the engine/radiator when the engine cools.

When cool, if I remove the cap, there is an air sucking sound as air is pulled into the engine/radiator. The lower hose going to the thermostat/water pump pickup does collapse when the engine is shut off after use. It reforms after the cap is removed as outlined.

I had Toyota service do a number of things, including pressure flushing and refilling the cooling system. They pressure checked the system-OK. There is a new radiator cap (1.1) and I replaced the coolant recovery tank hose since the one in there was very soft and would collapse when vacuum applied. The hose from the tank to the radiator pickup nipple seems OK.

So, after all this work, the problem still exists. Why doesn't the coolant return to the engine/radiator when it cools down?

Thanks for any help you can offer.
Old 08-10-07, 03:29 PM
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From all that you've said it almost seems like your recovery tank is acting like the problerm is where the coolant comes in/out to go in the tube to the radiator cap area, and that it is now acting like a one-way check valve. If the tube collapsed, that means that everything from the cap, including the cap on through the radiator and into the engine is most likely fine.

Now with the new tube, does that TOO collapse as it did before, or is it just the lower radiator hose? IF it is just the radiator hose, then all this might mean is that the new tube is stronger than the old lower radiator hose, and the problem is still in the reservoir.

You could do this experiment: After the car is hot and shut off, take off the tube off from the nipple by the radiator cap. Use another tube (you'd have to buy some more tube first) and hook up THAT tube and stick it into a jar of coolant and mark the jar where the coolant level is. Then come back out later and see if the engine sucked some in.

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