2007 Prius Gurgle Noise at Start Up After P1121 Fix

If you only hear the sound during startup and shutdown for about 10 seconds, it's the coolant pump working to pump coolant into the thermos. It's a normal operation, the pump is just getting noisy. There was an extended warranty on this pump but I don't think it would still apply to a 2007 model.

my 2006 makes the same noisy sound, but mine is more of a teapot boiling sound

 

Sounds like you are low on coolant. Check to make sure there are NO leaks. Once you confirm there are no leaks, then remove the upper splash guard over the radiator. When the ICE is "cold", remove the radiator cap. Look inside the neck directly underneath where the cap normally sits. If it does not look the picture below you are low on coolant.



If it doesn't look like this, then add the Toyota Super Long Life Coolant to the radiator until it is full. Then put the Prius in maintenance mode. Turn the heater on full blast and set the temperature on HI. Allow the ICE to warm up completely to cause the thermostat to open. If you rev up the engine some while it is warming up, it will make the thermostat open faster. Once the thermostat opens the coolant level will drop again. Once it drops down add more SLLC to the radiator until it is full. It might help you to open the bleeder valve on top of the radiator also to help get the air pockets out of the system. If you do open the bleeder valve, once you see coolant coming out of the valve close it up. That will tell you the radiator is full and that the air on top is gone.

The gurgling sound is due to trapped air. It sounds like the mechanic who did the work for you did not bleed the system properly. You need to get ALL of the air out of the system. Once it gets hot (summer time) and you start using the A/C the ICE will overheat if there are air pockets present.

Once you get the radiator full put the cap back on and drive it. Then let it cool down and repeat the process until the coolant level looks like the picture above when it is COLD. Once it does that, you are good to go. Then put the splash guard back on and pat yourself on the back for a job well done. It is a good idea to check the radiator when it is cold about every 30 to 90 days. Don't rely on the overflow bottle by simply watching it. At times the radiator can drain down and the bottle still look full. The only way to truly determine the level of the coolant is to physically remove the cap and look inside the radiator neck.

Lisle makes a great funnel for doing this work. Makes it real easy to get the air out and bleed it quickly. Also a airlift tool will help immensely. But you can do it the way I described above. It just takes longer.

Best of luck to you,
Ron (dorunron)

 

priusn00b,

Are you asking this question to JC or myself?

Ron

 

Thought so, just checking. I guess you know how to remove the splash guard over the radiator. If not, this is what you do.

Use a Phillips head screw driver. Apply slight pressure under each screw head. Start at one end of the splash guard and work your way to the other end. While applying pressure upwards by pushing up from underneath the splash guard GENTLY, rotate the little plastic screw CCW until it pops up. Remove the fastener and continue on down the line to the other end. Save all the fasteners as they are reusable. I think there is six or eight of them. Can't remember for sure. Traded in my Gen II for the Gen III I have now. Once you get all the fasteners out you need to slide the splash guard a little towards the back and then lift the front up to clear the grill and work it out from under the hood latch.

When you go to put it back together, do this to the fasteners. Hold the outside base end of the fastener and apply pressure to the end away from the screw head. The screw head will pop up and the bottom end will then be flush with the exterior of the fastener. This makes it real easy to put the fastener back in. Then simply work the splash guard back into place and line up the holes to the frame. Start putting all of the fasteners back in from one end to the other, then simply push down on the Phillips screw head. Once it is down the fastener will hold the splash guard in place. If you lose a fastener, take one to your local Toyota dealer Parts dept. and show it to them. Get a couple extras for next time. The usually cost a little over a buck so don't freak out when the guys says 3 or 4 bucks for 2 of them.

Best of luck to you.
Ron

 

Hi priusn00b,

Whatever happened to your issue?

 

Don't hold your breath, priusn00b has been seen here in almost 5 1/2 years. Plus, there are hundreds of threads where this issue is addressed and resolved. Use the Advanced Search function to zero in on only the Gen 2 forums.