Gushing Fluid Sound after Coolant Change

sounds like air in the coolant system. they probably didn't bleed it properly.

 

You are most likely hearing air in the heater core. The heater core provides engine heat to the passenger cabin.

If this work was done at a Toyota dealer, there's no excuse for the tech letting the car go with air in the system - very sloppy work. You can return your car to the shop and take your chances that the next tech will correctly do the job, or else DIY.

If you wish to DIY, invoke inspection mode. Make your car IG-ON (where the instrument panel warning lights come on) and leave the gearshift in P. Fully depress the accelerator pedal twice. Then shift to N and fully depress the accelerator pedal twice. Then shift to P and fully depress the accelerator pedal twice. Press on the brake pedal and make the Prius READY.

The hybrid vehicle icon will appear in the MFD and the engine will run continuously. Set your heater temperature control to max heat and turn on the fan to max speed. Let the engine run for a while; it may help to rev up the engine to speed up the process.

Hopefully after a while you will no longer hear air in the heater core. Turn off the engine.

After the engine has cooled down, check the radiator coolant level (look at the translucent expansion tank and fill with pink Toyota Super Long Life Coolant to the full mark). Also remove the black plastic cover over the radiator (secured with six plastic fasteners), remove the radiator cap, and check the fluid level. If it is not at the brim, fill with SLLC.

Keep an eye on the expansion tank over the next few days and top off with SLLC as needed, if the level drops below the full mark after the engine is cold.

 

Before you start this process, first check the coolant level when the engine is cold, both in the translucent reservoir and the radiator. Fill with SLLC as needed. If you find that the radiator requires substantial coolant to be added, then you may need to open the bleed valve on top of the radiator, driver's side, using a 6 mm Allen hex wrench. Look for the access hole to the valve, on the metal frame on top of the radiator. Opening the bleed valve will allow air out of the radiator. Don't forget to close the valve when you are done venting air.

The tech who had been responsible for the original job to drain and refill the engine coolant should have noted the amount of drained coolant. Then s/he should have refilled new coolant at least until the amount previously drained was restored (around 6 US quarts; capacity of a dry system is 9 US quarts).

Since you don't know how much fluid needs to be added, you should run the engine as long as necessary to get rid of the gushing sound that you hear. The engine thermostat needs to get hot enough to open. Expect to hear the radiator fans come on.

If you need to add fluid to the radiator, you can leave the radiator cap off while the engine is on, to keep an eye on the level. Check fluid levels frequently and add more coolant as necessary.

 

Consistent Great Advice !:rockon: