How To: Stripped V6 Timing Belt Tensioner Bolt

Putting this up for future reference to anybody that has this happen to them. This will save you about 6+ hours of work and cost about the same as a new oil pump+Toyota FIPG, etc.

Story time- finishing up my head/head gasket job and I decide to do a timing belt replacement while I'm in this deep. Order the kit from AirCabinMan on eBay and get to work. I've done ~10 timing belt jobs on the V6 over the years so I'm pretty versed on the work and have all the specific tools, etc. I'm almost done, getting ready to put the belt on and I go to install the tensioner/bolt. Set the torque wrench and get the dreaded "feeling" of aluminum giving way as I barely apply torque. Oh no! For those that haven't been here before- the tensioner threads into the oil pump housing. Now, the Aisin oil pump is a ~$100 part so not too bad, BUT to replace you have to drop the oil pan and the front diff (if you are 4WD). This is a serious amount of time and labor to complete, and you will still have a steel bolt threading into not much aluminum that could fail down the road.

I cried about this for a few hours and almost ordered the pump...but after searching around, it seems this is a pretty common occurrence on this and other aluminum engines from Toyota. I found a thread on IH8MUD that started me looking into a better option. A lot of mechanics would try to Helicoil this, but they have their limitations and aren't always successful. I also wasn't sure if they would seal, as the area behind this seems to have oil splashing around. A more expensive but better option is a Time-Sert kit. It looks like these are used to repair head bolt threads, industrial tool & die, molds, etc, so a meager belt tensioner should be an easy job for it. They use actual machined male/female threads instead of the Helicoil "spring" so they are sturdy and reusable (for that future timing belt job in 90K miles!).
Here's the basic rundown of how to install. Note that if you don't have experience with drilling/tapping, get an experienced friend to help because a lot of this comes down to the "feel" of how things are going. Watch the Time-Sert how-to videos as well.

You will need to buy:

$140 TIME-SERT Metric Kit M10 x 1.25 Part # 1012

TIME-SERT Metric Kit M10 x 1.25 Part # 1012

$25 TIME-SERT M10x1.25x14mm Insert Qty 10 p/n 10121

TIME-SERT M10x1.25x14mm Insert Qty 10 p/n 10121

$11 TIME-SERT Tap Guide M10X1.25 Part # 30125

TIME-SERT Tap Guide M10X1.25 Part # 30125

$22 IRWIN Tap Socket Set, Adjustable, 2-Piece (3095001)

Hanson 3095001 2-Piece Adjustable Tap Socket
You may also want to buy a new bolt and washer so you are going in fresh.
Bolt: Toyota 13556-62010
Washer: 90201-10098

So, this is what we are starting with. I think this was partially stripped before I got the truck (340K Miles) because this failed very easily.


Kit- You have a drill, a tap, a counterbore, and an installer/expander tool. Also showing the guide, and the Irwin tap to socket holder that you need (I couldn't get a T-Handle wrench to fit even with radiator removed). Also showing the inserts. The ones that come with the kit are wrong length, so make sure you buy the 10 pack linked above (14mm length).



Next- (instruction video here https://www.timesert.com/html/faq.html )
Drill out the existing hole using the guide (no pic) - Make sure you stop when the drill goes through so you aren't drilling your block.
Counterbore Hole (no pic) - Go slow and keep going until no more cutting happens, the counterbore stops itself at proper depth.
Check depth of hole with a caliper or probe and mark your tap to ensure you don't go too deep (you have about 8 mm of void back there so easy to figure this out). You want the full diameter of the tap body to go through ALL of the aluminum so that you have a full thread diameter all the way through.

Tap the hole with the guide. Make sure to use a cutting fluid/oil (Tap Magic is great, but even 3 in 1 oil will work). Also I vacuumed out as many chips as I could to keep out of engine. Most stay on the tap.

When done I removed oil drain plug and flushed through the hole with Kerosene to send chips down (doubt there were many but you never know).

Then, degrease threads with brake cleaner and a rag for optimal Loctite adhesion.



Next load insert and install with red Loctite on outside threads only! (Loctite is optional but recommended).
Follow instructions to "set" the insert with the tool. This expands the last couple of threads so it won't unscrew. Again mark the tool so you know when to stop threading it in. You want to go all the way into the insert + 1-2 threads.





Insert installed and ready to go:


And finally the new tensioner, new bolt, and new washer (between pulley bracket and oil pump) bolted up. Just need to install the belt and pull the pin.
Note new crankshaft oil seal, alway change when you are doing your timing belt.




I hope this helps somebody down the road! Please let me know if you have questions.
-Mike-

 

Thank You Sir nice Job and nice write up!!