Another Dealer Service nightmare - stripped oil pan threads

Thx to all for quick reply. My old service advisor was out today, so we'll have the talk tomorrow hopefully. I'll keep everyone posted. I also have a 2013 Prius and started work on that in August, that being the first oil change I performed myself (had about 5x10k mile changes from dealer). Both the bolt and filter cap were rather pristine and easy to remove on that one. The crush washer was like new and reused in that case. So I think I may have just ran into dumb tech (if you could call them that) on the 2010 Prius.

And thx again, I read all the posts very carefully. Special call-outs to these:

jzchen - thx for the feedback on crush washer appearance!
Chapman - thx for the inside pic of pan showing tap probably wont work due to thin walled "bolt" insert
georgina - thx for metallurgy (interesting!) and alternate tap tool rec! might consider that but pan threads seem thin.
bettergolf - comment about the filter coming off tougher than it goes on.
Mendel - for the oil change stats and TSB about the underpanel. I had the problem on mine but was out of warranty when I saw that TSB. been meaning to snag a new, used one from a junkyard someday, but they are hard to come by. I have installed a bunch of new pop-rivets from a $10 amazon kit and its holding okay for now.
Slamanader - thx for pics of bolts; and the caution about crawling under car! I have visions about kicking a breakerbar so hard to get off a stuck bolt, that the car wobbles on the jacks and falls on me! Important point to consider on tougher jobs. Jack stands just dont make me feel that great in any shape or form. I have a slightly different jack-up method but I'm hesitant to even share it since I don't want any liability - or to even think about steering someone wrong.

 

Thx to all for quick reply. Talked with my old advisor today; the shop agreed graciously to repair the damage. To be fair, they have been pretty good over the years, and probably the best Toyota dealer in Portland, considering the value, honesty, quality package. I also have a 2013 Prius and started work on that in August, that being the first oil change I performed myself on that car (had about 5x10k mile changes from dealer). Both the bolt and filter cap were rather pristine and easy to remove on that one. The crush washer was like new and reused in that case. So I think I may have just ran into careless tech (if you could call them that) on the 2010 Prius.

Now, the advisor mentioned to me that he has repaired "hundreds" of these, which was a bit surprising. He mentioned the pan metal is soft, and subject to wear, which I'm not entirely in agreement with, based on Mendel's and others history. However based on georgina's metallurgy details, I can see how the metal could degrade over time, especially if the techs are not careful and hand-tighten too much. Not saying they are right about that, but I suspect every seasoned mechanic thinks their hand has a built in torque wrench. So I questioned advisor on the repair. I said helicoil, he said yeah. I said no. Then I said time-sert, he said yeah, then I said maybe, but I doubt it. Then he said they have a kit to repair this. He said his main shop foreman needs to look at it too. I also said I need to be in the shop to inspect and agree to a solution. he agreed. I suspect we'll settle on georgina's tap and rethread solution, with a new drain plug and oil filter cap. he said replacing the pan is overkill. If the stamped drain nut has some meat in it to tap, im in agreement. I may ask to see a new replacement pan to evaluate it.

So using AAA, ill probably tow to the dealer on Friday ($20 cost), let them futz with it, while im standing around and see what we come up with. I'm probably going to get details in email tomorrow to avoid the hassle of the tow, unless I'm satisfied upfront with the expected outcome scenarios. If I had a lift or better jacking mechanism, id replace the pan myself, but its still winter, I dont like cold concrete floors, and I would probably need a better angle of attack for cleaning the block before new pan install. I have many other worthwhile projects to attack as well.

Will update the thread in a few days. Thx again to all the comment, I read all the posts very carefully. Special call-outs to these:

jzchen - thx for the feedback on crush washer appearance!
Chapman - thx for the inside pic of pan showing tap probably wont work due to thin walled "bolt" insert, and the comments about torque. I think there might be some value in dropping the torque a bit (2-4lbft) on both the plug and cap. I also think oiling a new crush washer each time is not a bad idea. its pretty tight on the bolt shaft and that might give just a bit more seating wiggle room. I suspect many folks usea new washer, wipe the pan clean and apply, leaving no new lubricating oil on the assembly. Ill probably change my practice on that to "lub" it up. I think it will also hlpe to keep that rubber film on the new washer from getting hacked up from the friction.
georgina - thx for metallurgy (interesting!) and alternate tap tool rec! might consider that but pan threads seem thin. will probably give it a try if the dealer kit looks good
bettergolf-comment about the filter coming off tougher than it goes on.
Mendel - for the oil change stats and TSB about the underpanel. I had the problem on mine but was out of warranty when I saw that TSB. been meaning to snag a new used one form a junkyard someday, but they are hard to come by. I have installed a bunch of new pop-rivets from a $10 amazon kit and its holding okay for now.
Slamanader - thx for pics of bolts; and the caution about crawling under car! I have visions about kicking a breakerbar so hard to get off a stuck bolt, that the car wobbles on the jacks and falls on me! Important point to consider on tougher jobs. Jack stands just don't make me feel that great in any shape or form. I have a slightly different jack-up method but I'm hesitant to even share it since I don't want any liability - or to even think about steering someone wrong.
etc - yes i got lazy on the 10k oil change intervals. I trusted toyota too much when they said 10K was fine. the car at 140k burns a bit of oil - 1/2qt per 4k miles right now. This isnt bad IMO, compared to some of the other burner stories Ive read about. I bought the car, expecting to go at least 250k miles, given the success of the G2 prius. these G3 seem to have a bit more issues. In general though its still almost like new, even after 12 years. But Ive always done good maintenance to it. Doing my own work is my attempt to nurse it back into health. I doubt i can lower the oil burning rate, but am trying now: EGR cleaning, oil catch can, Liqui-moly oil treatment, fuel treatments (sea-foam, gumout regane); very low OCI for a few cycles (3-3.5k).