Hi all, I could use some advice! I am working on a 2012 with 190k miles. This weekend I set off to change my engine and inverter coolant for the first time. I don't have any record of it being done before, so I am either a bit early or very overdue. The engine coolant went well, but when I went to take out the inverter drain plug, I absolutely could not get it free even with my breaker bar. I probably should have sprayed it with some PB Blaster and been patient, but alas I managed to strip the plug. I know there are methods to drill out/remove something like this, but I don't feel comfortable trying it for the first time on something this... expensive. Here are the options I am considering: 1. Reach out to the local dealer and see how much they would charge for a new plug and to get the stripped one out. I am also having a really hard time finding the part number for this plug - is it the same as the transmission fluid drain plug? I fear this option will be silly expensive and that a local mechanic would be better at getting the stripped one out. 2. Order a replacement plug and take it to a local mechanic to try and get the stripped one out. This relies on me being able to find the right replacement part. I imagine this would be cheaper than the dealer. For both of these options, taking out the plug would mean draining the inverter coolant, so I guess that essentially means I would be paying for the whole drain and fill process. This might be a stupid question, but would I be able to provide them with the bottle of coolant I already have for the filling process? I have very minimal experience with going to a mechanic so I have no idea what to expect on this front. Option 3, which I am leaning towards for financial reasons, is to find a hose somewhere that I can unplug to drain the inverter coolant as much as possible, and then refill. It wouldn't be as complete of a drain, but it's something. Then eventually when it's time to do it again, I do option 1 or 2. Does anyone have a recommendation on the best hose to unplug to get the most inverter coolant out? Thanks!
My first question to you is why.? You are talking about the hex plug in the transmission that drains your inverter coolant I get it generally all the ones I've done before I start and even get the what is it 8 or 10 mm Allen wrenched that fits on my ratchet and extension bars the first thing I do is take a ball peen hammer with the flat side and smack that gold or silver hex head plug dink dink then usually so far the last five cars I put the allen wrench in and the bolt almost falls out or starts turning with just my hand and not even a ratchet on the end of the extension and I just run it out my little catch bucket is there slide it under and then I get up and I remove the cover off the reservoir for the inverter coolant now it all comes out right quick Just takes a second then I put the plug back in and I give it a half a turn with the wrench
When you say stripped you have rounded out the Allen head? Do you really think you're in vertical and is gone bad or something that doesn't really do anything it could be water in there other than if you're somewhere when it freezes personally I wouldn't do anything about the drain plug you obviously haven't gotten it out so there's nothing missing top it up and leave it alone but if you must you can find somebody to probably drill it with a small bit then the next size up and a few sizes bigger and so on and eventually you'll get up to the threads minor diameter and then you can chase out the remaining fillings if you must.
Easy. Drill through the plug while carefully stopping before break through. Then drive a square tapered broken bolt remover through the plug and unscrew it. I would and did replace mine with a M18x1.4 19mm hex head aluminum oil drain plug and will never have the problem again. The M18x1.5 aluminum oil drain plugs are cheap on Amazon. Aluminum is compatible with the aluminum inverter case and less likely to corrode. The magnetic the drain plug will hurt nothing. A simpler method would be to use an internal broken pipe ripple remover from the hardware store, Drive it in to the messed up hex socket and remove the plug.
What was your set up; did you have ratchet wrench socket with 10 mm hex bit, a 10 mm Allen key with a pipe on it, a 3/8" allen key with the pipe, something else? @Georgina Rudkus suggestion should get it out; have a replacement bolt on hand before you do it. I'd recommend a long-handled ratchet or breaker bar, with 10 mm hex bit, for future removal. Get the bit solidly in there, and it takes a bit of oomph to break loose.
The steel hex socket headed plug is a carryover from the days of the cast steel differential cases. Toyota finds no need to add to the complexity of carrying an stocking an additional part and part number. Using a compatible aluminum plug with a 19mm hex head will mean that the hex socket plug stripping out will be forever eliminated. Toyota eliminated the magnet for the Gen 3 Prius inverter Using aluminum plug with neodymium magnets would be a plus.
