2004 Toyota 4 Runner 4.0L 1GRFE cylinder head bolt tap size

Everyone,

I'm in the process of changing heads on the 4.0L. I'm at the point I need to chase the head bolts internal threads, but am having trouble with finding the correct tap size. The head is a 12mm triple square head. Does anyone know the proper tap size and threads per inch? Please advise. Thanks in advance.

 

Pretty sure the size you are looking for is the M11 bolts.
Not a "common" size.

• 2 x Size = M10 x 1.25mm pitch - 86mm Long (with normal hex head)
• 16 x Size = M11 x 1.25mm pitch - 143mm Long

 

Thanks for the reply. You were correct. I have another question. I'm about ready to put heads back on, tapped all threads and clean up the block, pistons etc. As you know, now is the time to change out the expensive knock sensors, if they need to be. I didn't have any codes related before starting to change the head gasket, and truly do not want to spend unnecessary dollars, if they are good to go. The motor has 300K miles, 4.0L 2004. I was curious what other sensors besides the knock sensors make sense to change. I'm installing reman'd heads, the old heads had a little too much scarring in the cam journals for my taste. Final question, timing chain and components. The chain was changed at 160k miles, not sprockets, and it appears as though some of the other parts i.e. tensioners were changed. I'm a guy, history teaches us lessons to remember, since the first chain lasted 160K, i'm thinking change the whole ball of wax. Sprockets, chain, etc. But, the chain is not stretched, sprockets don't look bad at all (didn't mic them) visually. Its just a question, if you ever had a similar situation and didn't change the chains etc. and regretted it. Thanks again for your help.

 

Welcome aboard!

This is the TW subforum for members to introduce themselves. If you don’t get the answers here, then post in the “1st gen Tacomas” section.

 

Welcome to TW!

 

Regarding the knock sensors, if you didn't have any codes related to the knock sensors prior to the job, I would just test them with an ohm meter. If they check out, I would run them again. The FSM gives the ohm range required when testing them. I would also check the wiring harness that runs in the valley to the sensors prior to reassembly.

 

try not to use a tap. the threads in the block are pretty important. cutting isnt ideal. use a re-threader to bring the threads back into shape.


when i rebuild the motors at work its usually just clean the threads out, clean the bolts up, make sure they go in by hand smooth, then lightly oil the threads and install (after measuring for stretch)

(source - im the one that has to timesert the blocks that headbolts rip threads out of, rare.. but it happens)

 

Thanks zguy1, I'll check ohms and not worry about it. Thanks for your reply.

 

Thanks Empty_Lord, I bought new bolts, ran the new bolts down after thread cleaning, all apears smooth. I bought a new set of thread chasers, but they were not long enough. I ran my taps slowly with cutting fluid and really didn't get too much debris or shavings. I think I'm good to go. I will surely put some oil on them and install. Thanks a bunch for your reply.