kaws03

Hello everyone,

I took my 3uz a little apart in my work's parking lot, for a valve clearance adjustment (my car came with stupid LPG )


Undid 17/18 head cover bolt and the very last one, in a most annoying location possible just did not want to cooperate (the rest were literally finger-tight)
I decided to give it a little massage and pushed it clockwise. The bolt lost it's head immediately


At least I could take the valve cover off now.
Took both camshafts out, gained more space, tried the whole available arsenal, poured whole can of WD-40 in.
Ordered a roller-type extractor, was total rubbish, too big, won't grip at all, lost week waiting for it


Had the best luck with vice-grips, got it unstuck- started moving like 10-15 degrees back and forth, with huge force, but I was celebrating the victory at this point.
Though, no further progress was made
Found a drill chuck laying around, took two adjustable wrenches and went for it



Slipped two times, ate away all the thread leftovers, finally bit in properly and... voila





Now, finally, to my question:
Is it ok to just abandon it? I don't want to even try drilling it out, have zero experience with that.
Should I add any sealant around this specific area, or would it be ok as is?
After all it got 8/9 bolts perfectly intact. Still it is a corner bolt
I am, surely, installing brand new OEM gasket
Anyone been in the similar situation?
Thanks!

firelizard

iTrader: (1)

Very likely to leak if you don't replace it so the valve cover can be torqued properly all the way around.

kaws03

Oook, too bad. Then I'll try applying sealant from the closest half-moon to the next available bolt, both on the head and cover itself.
And if it leaks- i'll take it to someone, who's actually beyond a youtube-certified-mechanic

My concern is that either engine or the complete head will have to exit the vehicle, because of unfortunateness of a location
And that would cost me a kidney

P. S. In case it was a little too sarcastic- the bolt has snapped at the very bottom, and rest of it is still dead stuck inside the head

dwoods801

Wow that sucks! Usually the cover bolts have the opposite problem and constantly work themselves loose. Certainly you can try adding some silicone gasket maker but that usually guarantees a bad seal and you’ll find it’s leaking right away. Which isn’t the end of the world, but I would try a few other tricks to get the rest of the bolt out. It looks like there is just enough bolt there to get ahold of with a good set of vice grips or the right pliers. The trick to making sure it’s easy to get out is heat, get a little butane torch and heat it up til it’s smoking, and then be careful not to burn yourself. But that should make it easy to remove, the other option would be getting a flexible attachment for your drill, and then getting a reverse bit that is designed to make a small hole in the top of the bolt, and as your drill cuts that hole, they usually bite in and spin it out. The other option is to find a nut that fits the bolt, tighten it down and then fill in the top of the with a welder, then you’ll have something to turn with a wrench, and the heat from welding it will usually make it easy to take right out. If you don’t have access to a welder, you might try a little red lock tight on a nut. Just make sure to use the locktite gel and let it dry for at least a day or two, just use a tiny bit, you don’t want it getting down into the head and making it harder to remove.
good luck

kaws03

Thanks a lot for your suggestions, @dwoods801
I did try heat, I used small jet type lighter and was heating it for about a minute. I then immediately sprayed WD40 and tortured it with vice-grips
Felt super scary with all that oil around, kept the extinguisher next to me, hehe
No luck... It won't budge no matter what. I don't know what the heck is wrong with this bastard, but feels like someone epoxied it in there.
Right now it has, at best, one turn of the thread sticking out, and welding or drilling are the only options. Not qualified enough for both
​​​​​And I am 101% done with it, at this point I'll be trying to find someone who knows their thing at this type of work, again... if it leaks.
I hate putting silicon where it should't be, and that's exactly why I spent a week fighting that son of b... at this point I am happy with whatever works
I'll update the thread on results. Everything is done and I am hoping to put everything back during a weekend.

That was exactly the case with all of the 17 other bolts. I could've taken them all out without a ratchet
Car has 160k miles on it and I am the first to open the heads.
Funny thing that I was also the first to replace the timing belt and pump last summer. Both looked decent. Good job, Toyota

kaws03

That part is little surprising to me. Do you think I might have better chance without that extra sealant?
It feels like covers are pretty strong and won't really bend enough in one particular spot, to make a gap...
I also can apply tiny bit more torque to compensate for the missing bolt. 7.5 n.m is not much, totally sure they can handle 8 or a bit more

dwoods801

Try heating it up again only this time don’t use the WD40 or anything that will cool it down. The problem with the valve covers is the little grommets that go under the top of each bolt. If you tighten any of them just a little too much and the grommet gets destroyed. Even in the best circumstances it seems like you have to retorque each bolt yearly or they start leaking again. You can try whatever you think is best, worst case scenario is you just have to pay attention to the oil level more often. Which is pretty standard with this engine anyway, the valve covers are a constant battle in my car

kaws03

Have you considered getting rid of rubber grommets?
I, honestly, don't understand their purpose, like, at all
They don't seal anything (bolts are outside of the gasket's perimeter)
They could've protected threads from rusting, but there's a gap between cover and head anyway
So .. what do they even do?
Maybe they somehow prevent loosening, but spring washer would do better job, won't it?

dwoods801

I have definitely considered it. I am pretty sure they are designed to seal up the bolt hole, and offer some resistance combined with the gasket itself to slow down the loosening process? When I bought them last I saw several different manufacturers offering similar ones for their vehicles and I thought about buying some that were much cheaper and for a ford 4.6/5.4 V8’s but yes, if anyone finds an alternative I would be very interested! But even if you keep them perfectly torqued, they start to get hard along with the valve gasket and need to be replaced every few years anyway.

dwoods801

I wonder if you could get a hacksaw blade in there to cut a groove across the top, so you could use a flat screw driver to turn it, after getting it hot? Even a metal blade for a jigsaw or sawzal, if a shorter or smaller blade would be easier? If cut a nice deep line across the top, got it red hot, and used a nice big flathead? Even if you have to put the screwdriver in place and then give the end of it a few good whacks with a mallet to make sure the screwdriver gets in deep and solid? Just an idea, you could even cut an X and then maybe use a Phillips screwdriver?

kaws03

Unfortunately I don’t have proper tools for a job in my possession
And cutting a slot manually with a little file would take another week or more, haha
So my current plan is to gradually increase torque over spec (6 n.m.) on closest bolts like that

kaws03

Hello there!
I am back
I don't have any updates on my situation, but...
There is a friend of mine, who was having exactly same situation. He is definitely not in EU, and definitely DEFINITELY not me

He got some 70% Nitric Acid,


made it a 30-35% one with help of distilled water.
Prepared a car for a surgery, by covering everything around


He made a little funnel out of plasticine (it is resistant to Nitric Acid), and nicely secured it over the stuck bolt leftover.


He told me, that it was very important to also block the bottom part, also with plasticine. Otherwise- the through-hole will let the acid through.
Surfaces need to be cleaned well (Scotch-Brite does a great job), so all that seats tightly, and nothing leaks.

He then added some acid into funnel with a syringe and waited about 1,5 hours. Acid gets "worn" and needs to replaced. So it gets sucked out, and new portion is brought in.
Overall it took him around 10 hours and 6 acid changes (3-5ml each) to get bolt dissolved completely.

He then neutralised acid with some water/sodium mix. Removed funnel and bottom plug, cleaned everything thoroughly with acetone and a little straw brush.

Aaaand he got a perfectly clean, brand new looking thread.





Pure magic

His valve cover is now torqued properly all the way around




If you ever wanna follow his way- be careful, it's a powerful acid, so wear eye protection and gloves. Protect surroundings.
Work with small amounts, use common sense.
I am not taking any responsibility for you getting hurt.

Try to find plasticine that is soft and sticky. First try was with a regular, kinda hard one, and it sucked biiig time. It won't stick at all, and acid would escape everywhere. Not good
You also need to cover all the sensitive parts of camshaft with assembly lube, otherwise acid fumes would build some surface rust on them
And, obviously, method only works for aluminium parts with steel bolts inside.

Peace!