Inverter Coolant Leak: T-SB-0352-09

I noticed a TSB for 2010 models which the group might be interested in. The inverter coolant drain plug might not be properly torqued, which would lead to a coolant leak.

If you notice that the inverter reservoir coolant level is dropping, I suggest you look for a fluid leak at the drain plug and verify tightening torque, which should be 35 ft.-lb. Replenish coolant as needed with Toyota Super Long Life Coolant.

Note that the 2010 repair manual shows the drain plug tightening torque should be 29 ft.-lb (which is the same as Classic and 2G). I assume that the TSB was issued because 29 ft.-lb was found to be insufficient given field experience.

 

Looking at the repair manual drawings, the plug seems to be the normal circular plug with a 10 mm hex hole.

However the transaxle case is certainly different. Maybe the aluminum wall thickness is less than 2G. I'd recommend caution when tightening these plugs, use a torque wrench for sure.

BTW, the 3G transaxle ATF fluid drain and fill plugs also require a 10 mm hex key. The 2G transaxle case had some plugs using the circular design while other plugs had a hex head requiring a 24 mm socket.

 

techinfo.toyota.com

 

The inverter and transaxle are both included in the same coolant loop. The coolant fill is performed at the reservoir adjacent to the inverter, while the drain is located at the bottom of the transaxle.

The engine coolant loop is separate and unrelated to the inverter/transaxle coolant loop.