Stripped Head Bolts

So I finally got around to replacing the head gaskets on my wife's 2005 Tacoma (4.0) since both banks had exhaust gasses coming into the coolant.

I got the passenger side head off, and 6 of the 8 bolts (plus the 2 12mm bolts) on the driver's side. However, the front two triplesquare head bolts are rounded out.

What's my best course of action to get these bolts off? These head bolts seemed to be torqued higher than my 7.3 powerstroke, so it's going to take a lot of force to get these two out.

Should I grind the bolt heads off, then hopefully be able to take the rest of the bolts out once the head comes off? I'm worried about getting a bunch of metal everywhere in the head and cylinders, but I don't seem to have much of a choice with what's going on.


Any help or advice would be appreciated!

 

How did you manage to round off a 12 point fastener?

 

I wish I knew... Oreilly's was the only place with a 12point 12mm socket set in town. They are Lisle brand, made in USA, and were 55 bucks for the set. The bit itself rounded, as well as the bolts themselves.

I was able to get another set under warranty, and the second set started to slightly round as well once I got to those front two damn bolts.... It managed to get the other 6 bolts out, but the first two won't come out. I'm going to see if I can get a 10mm 6 point socket head bit because that seemed to squeeze in there a little tighter. I'm having doubts it will work, but anything before trying to drill it out.

 

If they are rounded there's not much left to do except cut the heads off.

I wouldn't worry about filings. Just plug the galleries with rags or thin plastic bags and giver' You'll be cleaning everything anyway.

 

Maybe try a bolt and nut remover kit ?

 

Thanks for the replies. I'm not too sure if a bolt and nut remover would fit in between the surface of the head. I did manage to get one of the bolts out with a 10mm allen head bolt. I hammered it in and used a breakerbar and pipe to get it out. However, the inner front most bolt stripped even more with the allen head bolt so I may be cutting that head off or trying to drill it out....

I'll see if I can hammer any other bits into there, but if not I'll start cutting away... hopefully, if I do have to cut it out, the rest of the bolt will come out relatively easily without the tension of holding the cylinder head in place. I'm a little worried that a torque-to-yield bolt will be somewhat stretched in the threads, making the remaining threads still clamped in place.

 

Soak the bolts overnight with acetone/atf mix or liquid wrench.

 

Might try getting a socket drove on tight then if possible put a impact wrench to get it loose. Sometimes the rattling effect can do wonders.

 

When you the bit itself rounded do mean the 12pt socket?

 

Yes, both of the 12 point sockets started rounding out as well as the inside of the bolt. I'm not really sure what went on there. I got all other 14 head bolts out, but these two were really giving me issues. It's possible I had the socket at an angle when trying to get them out, but the socket fits in the bolt pretty deep and tightly so having it at an angle would be pretty hard to do, and they were the front two bolts which are easier to deal with.

I ended up cutting and grinding the last stuck bolt head off. I still need to cut it down a little because the washer is stuck on there still, but I can see the bolt spinning now so I don't think it will be stuck in there once I get the washer out from the remains of the bolt head.

I'll have a lot of cleaning to do though... there is metal debris everywhere from the dremel grinding and cutting.


I sure hope it's just the gaskets that failed and not the heads....... Apparently the 2005 and early 2006 head gasket design was different and it's a fairly "common" problem for these to fail in this year range.

 

Well here's what everything looks like. I haven't clean anything yet as you can tell. I'm hoping I can just clean things up real good, prepare the gasket surfaces, and throw everything back together.


















I didn't see any obvious signs of head gasket damage, but I know it's not necessarily easy to detect.

 

Damn. I’ll shut up and quit bitching and moaning about this one fastener I cannot reach on my motorcycle. Yikes OP!

best of luck.

 

I can’t see the pics, you said the inside of the bolt, are you saying the bolts are torx head bolts.

 

Haha thanks. I've done a lot of work on vehicles, and I have to say having a stripped cylinder head bolt is one of the worst things happen. I'm a little nervous about torquing the new ones on if this one stripped so hopefully I don't run into any issues with that. Now that both heads are off, I'm just going to clean things up and throw everything back on. I hope these Toyota gaskets I ordered are the updated gaskets!

Does anyone happen to have a good reference to torque values and sequences on this 4.0 motor?

 

Glad you got them off.

 

Sorry I just updated so the pictures should show now. The bolts are a 12 point style bolt. I think it's called triplesquare bolt.

 

Wow. I’m used to seeing a 12 point bolt that requires a 12 point socket. I don’t like that fastener at all.

 

Might be in here https://www.tacomaworld.com/threads/the-torque-spec-guide.318116/

 

Yeah I definitely don't like it either. Not sure what advantage it's supposed to have but it didn't work out to well for me! Plus the bits are not common to get either.

Thank you it looks like that has all the torque specs I need! I don't think it will be too hard to find torque sequences so I'll look for that next.

 

@Torspd