Head is off, need initial diagnosis

[jcardona1]

1996 LC, 167k miles

Need some input from the head gasket experts! Just pulled the head last night on my LC. Anything look abnormal to you guys? I'm particularly concerned about the last two head bolts on the passenger side being covered in crud. Does that happen a lot? It started leaking coolant out the back of the head at #6 so I knew I had a leak.

Full details in my build thread (link in sig). Anything else I should look out for? Truck ran fine and never overheated prior to pulling the head. Thanks!

Copy/paste from thread

Cylinder #1. This one was DONE! Check out the severe deformity of the firing ring.

Cylinder #2, same type of deformity.

Cylinder #3, same thing

Cylinder #4, same thing

Cylinder #5, same ol' story

And the infamous #6, a little more firing ring separation on this one

Water ports towards the back of #6. These sections were toast.

This head bolt in the back corner was tough to remove. Bolt was covered in crud. This metal piece was completely loose from the gasket and I think it let stuff seep into the bolt hole.

2nd-to-last head bolt on the passenger side. FULL of crud.

Back of the block and the transmission housing. You can see the dried up puddle where coolant was leaking out.

And here's the front part of the gasket, around the timing chain housing. This piece was destroyed!

Metal part of the gasket was lifting away.

Some dried up gasket material towards the front. Is this normal? Did it come from the factory with gasket sealant up here?

 

[SierraMtns]

Makes me wonder what my gasket looks like at 150 K miles.

 

[Frankencruiser]

I'm sure someone with more experience will chime in, but to me it looks like that gasket was slightly mis-aligned at installation.

Are you sure the head had never been off before?

 

[Pin_Head]

The diagnosis is you need a new had gasket.
Wheter it needs anything else remains to be seen.

 

[scottryana]

Yeah get that headgasket out of the way, lets see what the block looks like, pay special attention to the back of the block behind #6. Sometimes there is some wasting away back there that will continue to leak unless the block gets a little surfacing.

 

[jcardona1]

Thanks guys. I'll be starting to scrape away the gasket today. No idea if the head was ever removed. The PO said he didn't know anything prior to him owning it.

What's the best way to assess the block's condition myself? Straight edge?

 

[Gumby]

There's a number of things you're going to do that makes most of your worries irrelevant.

You're going to have the head checked for flatness, cleaned and pressure tested.

You're going to use new head bolts.

You're going to run a tap down each of the head bolt holes to clean them up.

You're going to use new coolant.

You're going to use a new quality head gasket.

Yes, head bolts get crudded up. Yes the deforming of the head gasket is normal. Yes, the cooling passages get nasty when the coolant maintenance is ignored. None of that really matters because you're going to fix it all before you put it back together. And you would every time regardless of what it looks like.

 

[Gumby]

I'm sure someone with more experience will chime in, but to me it looks like that gasket was slightly mis-aligned at installation.

Are you sure the head had never been off before?

The head gasket wont fit on misaligned since the centering dowels are still there. The head gasket will experience some movement due to heating cycles and dissimilar metals on either side. That one looks like it moved a lot.

 

[jcardona1]

There's a number of things you're going to do that makes most of your worries irrelevant.

You're going to have the head checked for flatness, cleaned and pressure tested.

You're going to use new head bolts.

You're going to run a tap down each of the head bolt holes to clean them up.

You're going to use new coolant.

You're going to use a new quality head gasket.

Yes, head bolts get crudded up. Yes the deforming of the head gasket is normal. Yes, the cooling passages get nasty when the coolant maintenance is ignored. None of that really matters because you're going to fix it all before you put it back together. And you would every time regardless of what it looks like.

Thanks for the input

On the head bolts...would you recommend new ones even if they are within spec per the FSM? Those little bastards are expensive. $13 each x 14 bolts! But in the grand scheme of things it's a small amount to pay for peace of mind I suppose...

 

[Gumby]

If you checked them and they are within spec, then, according to Toyota, you can wire wheel them clean and re-use them.

 

[baggar11]

Really? I was under the impression that the toyota head bolts where torque to yield and should only be used once.

If you checked them and they are within spec, then, according to Toyota, you can wire wheel them clean and re-use them.

 

[jcardona1]

Really? I was under the impression that the toyota head bolts where torque to yield and should only be used once.

I've read a lot of conflicting info about the head bolts. The fact is the FSM doesn't say they are one-time use, and in section SS-4 it gives the specs to measure the bolts, so that gives me the impression that they're reusable. I'm torn on the subject....

 

[baggar11]

I'm most likely wrong on this, but maybe the FSM is referring to checking the specs on new bolts. Making sure you got new bolts that are within spec. I hate spending extra money too, but repeating most of the head gasket work would be brutal in mind opinion.

I've read a lot of conflicting info about the head bolts. The fact is the FSM doesn't say they are one-time use, and in section SS-4 it gives the specs to measure the bolts, so that gives me the impression that they're reusable. I'm torn on the subject....

 

[Splangy]

I'm most likely wrong on this, but maybe the FSM is referring to checking the specs on new bolts. Making sure you got new bolts that are within spec. I hate spending extra money too, but repeating most of the head gasket work would be brutal in mind opinion.

Nope, the FSM refers to checking the old bolts. It says to replace any that don't meet spec with new bolts.

 

[jcardona1]

Checking the spec on new parts doesn't seem likely. I'm like you, I hate buying stuff I don't need. If the FSM says they're not reusable, I'd have no problem buying new ones. But I'm just not sure on the head bolts. Here's another screen shot. FSM shows non-reusable parts with a diamond character. Nothing on the head bolts

 

[powermad]

I wrench for a living, everything I have seen always has a note saying to replace bolts if they are needed or to check them.

Generally it says to remove and discard in the dissassembly section if they are one time use.
Then again upon assembly.

 

[Michael Hanson]

I have reused the bolts from 4 of our cruiser with no problems after 100,000 miles. I do realize this is not many in terms of an experiment. Mike

 

[scottryana]

Cheap insurance, stretch to yield bolts, just replace them

 

[acidrumz]

My head bolts were reused and are within specs according to the fsm. 10k miles so far.

 

[blkprj80]

When you torque your head bolts, just pay attention to how much of a turn you get for each bolt to go from one torque value to the next. You do it in a couple steps at least when you torque the head. If each one is going a quarter turn or whatever, they all should be going nearly the same amount before the wrench clicks. If you find yourself going near twice as much travel on a pull than the previous head bolts, get scared and start to worry about how you're going to unload the torque to replace that bolt.

I believe if you clean the threads in the block and on the bolts, you will be okay if you lube the threads with the suggested lube in the FSM. I'm thinking motor oil?

These bolts stretch when they are torqued. In doing so, they suffer a reduction in diameter each time. There is a specific section you need to measure.

If you find a couple that are questionable, shoot me a PM. I have about 13 of those bolts. I used one with a notch ground in it to chase the threads in the block. Then I put in studs. You're welcome to whatever you need.