Head gasket change in action…no threads on timing chain?!? Help

can you post the video, and the point at which they show/talk about the threads?

 

I confess I am wondering just what you mean by threads.

 

Ditto, do you mean the colored timing links? Or the dots on the gears? I do not understand threads. You need to remove the tensioner, harmonic balancer and the timing cover. Then you can line up the timing marks to move forward.

 

Forums have “threads” too??

 

Looks blown to me:

The holes between cylinders are coolant passages, and where the black layer is worn off coolant is able to seep into the cylinders:

One of the head bolts broke off? You definitely need to get that out. Gasket Masters thread "shocking the thread" discusses dealing with stuck bolts:

And how to deal with broken off bolts:

^ You'd want to be real careful to not spill drill shavings into the cylinder when doing this. Maybe one person drilling, and another with a vacuum right beside it. Then use compressed air on the whole area.

It "might" be worthwhile to get a mobile mechanic to do this?

Towards the bottom of my signature there's a couple of head gasket related links. The GM video likely has the head bolt torque sequence/method, but might be some additional info, in the Repair Manual attachments.

 

Yeah those are coolant passages, maybe just residual.

 

GM use reverse thread bits for the whole extraction process, but I think it’s more traditional to drill pilot hole with regular bit (turns clockwise) then switch to a special bolt extraction bit, which has aggressive reverse threads, with the drill set to counterclockwise. The latter drill set usually comes with a table, recommended pilot drill bit and extract bill bit diameters, for bolt diameter.

it doesn’t hurt to start with even a smaller than recommended pilot drill bit, a little easier to control, avoid going off center.

Really take your time with this; the last thing you want to do is chew up the threads of the head bolt hole.

if it’s going off-the-rails, a mobile machine shop guy could be a godsend.

 

As a DIY project probably safest to purchase new head bolts, just a better safe than sorry thing. There are specs for checking them though. In one of the head gasket links in my signature, in one of the repair manual excerpts linked.

I forget what GM video says, but repair manual says oil-soak the head bolts before install, say plunk them all in a can of motor oil.

 

Head bolt installation followed by timing chain and cover installations are very critical. Use of a proper torque wrench followed by further angle tightening can save a second head gasket fail and the need for proper timing is obvious but too often messed up. The timing chain cover sealant is also critical to avoid oil leaks and rework.

 

How many miles/kilometers on the odometer?

Is anything being done to address the pistons and rings? The rings are probably seized due to carbon buildup, which lead to oil burning, and more carbon buildup, etc.

Severe cases can have scored cylinder walls and severe oil burning issues. If the cylinder walls are scored then doing a head gasket alone is a waste of time and money.

Posted via the PriusChat mobile app.

 

You can crank the pistons by putting a socket on the bolt* on the end of the crankshaft (through passenger side wheel well), and turning (clockwise?), which can move the pistons up/down, to check for scoring on cylinder walls. Also, when the various piston come up to Top Dead Centre (TDC), you can check that none of them are lower than the others. This is a rough check for piston arm being bent (due to hydrolock, which can occur due to sufficient uncompressible coolant in cylinder).

* Is that bolt removed right now? Could be temporarily reinstalled.

 

Don't stress. If you go slowly, take photos/videos and you'll be find. Go ONE step at a time.
The head bolts are inexpensive, worth changing. You could measure them all, the are stretch bolts,
and need to be withing a certain amount to reuse them.
Every other bolt can be resused. Unless the are damaged of course.
All gaskets should be replaced. They come in the FULL head gasket kit.

The timing "chain", not belt, is really not difficult. Again, if you go slowly.
If you set the cams on there marks, and the crank is at tdc for #1.
There are 3 marks on the chain that line up on the 2 cam sprockets and one on the crankshaft.
"Almost" impossible to get wrong.

The timing cover is the trickiest to install. It's a tight fit and a little hard to align. Do NOT try to
force it into place! Go SLOW, try to get it aligned and ease it into place. Have bolt Toyota says
to install to hold it in place. Then install the others and torque them down. Follow the procedure
for tightening them and you won't have a problem. And intall the Toyota silicone like they show.
It won't hurt to be a "little" extra especially where the head sits on the block and the block and oil
pain fit together.