Shudder, cylinder 3 misfire, check engine light

I see a lot of bad reviews and have not used one myself and it looks like everyone is using the same manufacturer and putting their name on it. Buyer beware!

 

The Repair manual says to torque to the spec'd value, paint a mark on the head of the bolt, then go another 90 degree, and a further 45 degrees. This doesn't seem ultra critical.

Also, has anyone mentioned the bi-hexagonal socket driver. If you google that you'll find lots of sources, on Amazon.

 

It's also a 12mm bi-hexagonal wrench, not 10mm. Don't ask me how I know this - I specifically paid $40 for the AST 10mm bi-hexagonal wrench to find out that it is the wrong size.

Note: I used a triple-square bit in lieu of the proper bi-hexagonal. I heard they are similar but not identical. But it worked fine for me...

 

You were for sure the first one removing those bolts? Grasping at straws...

FWIW, here's a Toyota tool description and part number:

Toyota tool: 10MM BI-HEXAGON SOCKET p/n: 09013-7C310

 

Noticed this comment, on a replacement head bolt amazon page, coroborates your experience:

 

At about 17:50 in the video I linked (first page, post #12), he describes the head bolt socket as "number 12", which I think means 12 mm. Snap-On I think?

 

Head bolt part no's are in this tsb:

 

Mine were 90910-02166. So it may be different depending on VIN (or it was superseded); I had my parts guy look up by VIN.

 

I am the original owner of my Prius and I have never had any head work done.

The socket was still on my workbench. It is definitely a 12mm “XZN.” Not saying it is the correct one, but it fit securely and I was able to do the job.

 

You probably used a 12mm triple square. The correct tool is a 10mm double hex. The angles of the points are different, buy the 12mm triple square will usually work.

If anyone reading this would like to know, here is my recommendation:

CTA Tools 9295 Toyota Head Bolt Wrenches –Double Hex 1/2-Inch Square Drive Set

Posted via the PriusChat mobile app.

 

Here's a pdf of triple square dimensions:

http://www.metalnerd.com/content/assets/43/439614/Specialty_Bits_and_Drivers/triplesquaretable.pdf

The point-to-point dimension of a M12 triple square is indicated as 11.6 mm.

If I draw a hexagon with 10 mm face-to-face, the point-to-point dimension is 11.547

Here's a 12mm triple square (magenta) per the pdf dims, superimposed with a bi-hex 10 mm (cyan):


The (magenta) triple square protrudes slightly more at the points:


That's in mm's, and jives with (11.6-11.547)/2

There'll be some tolerance factor in the bi-hexagon, I've just drawn it 10 mm face-to-face exact.

 

Thanks!

Now that makes perfect sense. Thanks for the analysis.

 

The "Torque Turn to Tighten" method is done to achieve a consistent clamping force. Suggest following the procedure exactly as described.

http://www.boltscience.com/pages/a-case-study-in-torque-angle-tightening.pdf

 

I recall a while back someone mentioning that a 10 mm hex wrench fit perfectly. Obviously not the right tool, but corroborates the size/shape.

I'd still like to understand the underlying dimension of the triple square series. An M12 for example, does it have a 12 mm dimension in some direction? You'd think so. AutoCad's good for sussing out stuff like that.

Off-topic rambling:

I was a draftsman and checker for years, and one thing I found frustrating was translation of measurement method. A case in point was a tunnel, and conveyor belt line, shown on Materials Handling arrangement drawing with slope of 1.1935 degrees. I went around asking everyone what was with this number; no one could come up with an explanation, recall where it came from.

One of the Structural draftsmen wandered over, said he recalled it was 1/4" in 12" pitch, at the outset.

 

Had this issue and posted in other threads detailing it from other users. Turned out to be the intake manifold getting gummed up where the EGR system connects to it. Replacing the manifold solved the problem.

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