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Anyone Fixed A Stripped Block Thread (Head Bolt Holes)?

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Avensis T3-X 2.0 Petrol 2005 1AZFSE

108 miles

Head gasket failed and it appears the thread of one of the headbolt holes has been stripped causing this.

Keen to hear if anyone has had a go at using timeserts or helicoils to repair this before. Or if I'm simply better to bite the bullet and try a and find a recon engine. Mechanic didnt notice the thread was stripped until they went to fit the new gasket and torque down the (skimmed) head. So now im looking at a bill of replacing a gasket, skimming the head and possibly a new engine.

Any advice much appreciated

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Sounds like the thread was stripped when the head was being torqued down as these bolts don't just strip the threads. Having used heilcoils quite a lot during various jobs I can tell you if have the clearance to drill and fit the helicoil then the repair will be as good as the original thread

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Avensis T3-X 2.0 Petrol 2005 1AZFSE

108 miles

Head gasket failed and it appears the thread of one of the headbolt holes has been stripped causing this.

Keen to hear if anyone has had a go at using timeserts or helicoils to repair this before. Or if I'm simply better to bite the bullet and try a and find a recon engine. Mechanic didnt notice the thread was stripped until they went to fit the new gasket and torque down the (skimmed) head. So now im looking at a bill of replacing a gasket, skimming the head and possibly a new engine.

Any advice much appreciated

Hello mate,

As Kenny says you can use helicoils providing you don't drill into the water jacket or Oil galleries.

I'm not saying that this is the problem but I believe that on some 2 ltr petrol models the threaded holes in the block were not drilled deep enough causing head gasket failure as the head would not have been torqued up correctly when the bolts bottomed out. So before it is reassembled it is worth checking this out by measuring the head and gasket thickness then add the depth of the threaded hole it the block, I would expect you will need the head bolt to be around 5-6 mm shorter than the total measurement to be on the safe side to avoid bottoming the bolt when torqued down. You may be able to grind a couple of mm from them to be safe and this will be more important now the head has been skimmed as the head will be thinner giving a greater chance of the bolts bottoming out.

I hope all this info doesn't add confusion to the problem you already have and don't forget .... check all the holes!

Good luck and regards ... Pete

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Hi,

I have a similar problem on a 2003 RAV 4 with one of the head bolts stripping a thread in the block

The mechanic is saying that the hole in the block is too deep to use a helicoil.

Has any one managed to use a helicoil on a RAV 4 Engine block?

Is there a kit available?

I would be grateful if anyone can offer some words of wisdom.

Andy :driving:

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is the block realy that soft that it can strip a thread just torquing them up?? regardless of them bottoming out. i would say they were stripped coming out i have seen lots of people take the head off adhoc then carefully do the headbolts up in the preset sequence.

i assume the o/p is using new headbolts??? or do these ones not stretch. on the rover 25 i had they had stretch bolts and u were supposed to messure them to see if they can be reused. thing was a new set was 35 quid and as u couldnt buy em singualy u might as well buy new ones to be on the safe side

coop

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have had snapped head bolts in the block ive had to get out but never the thread stripping - doesnt sound good

this would annoy me if i repaired it

it would always be in the back of my mind that it could probably fail

id just get an engine for it

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If you can find someone confident to do the repair then that has to be your most cost effective method. A new engine sounds a bit drastic to me - but I have never had to deal with this myself.

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Trying to give you the best advice sat in front of a PC is always diffiicult and this is not a common problem so a good engineering shop should be your first port of call for advice on this. The problem is that I bet the engine is still in the car which makes life even more difficult for them to see it.

Even if someone has had this problem before it may well be in a different place in the block so it's hard to be 100%.

Regards and good luck with it,

Pete.

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Sounds like the block is knackered, BMW 6 cyl engines suffer from this once engine has overheated the block has lost its mechanical integrity. The mechanic may have been careless but I doubt it. Being in the taxi trade I have heard about and seen lots of toyotas scrapping blocks because of overheating. If it was me I would buy an engine from a good engine rebuilder and fit that, I suspect that the rest of the threads will be weak and fail after a short time.

Taxijim

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Just repaired a 2003 rav 4 with 3 stripped headbolts at the rear using Helicoil.Who says its imposible ?It depends upon how you install the kit properly.I actually had some photos on how its properly done.

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Just repaired a 2003 rav 4 with 3 stripped headbolts at the rear using Helicoil.Who says its imposible ?It depends upon how you install the kit properly.I actually had some photos on how its properly done.

That's interesting but have you run the engine long enough to make sure it's going to last?

What material and finish helicoils did you use ie were they stainless or phosphor bronze or whatever and what protective finish on them?

Did you drill out the holes by hand or did you manage to get some sort of drill press rigged up (assuming you didn’t take the engine out) to avoid bell mouthing of the holes and off square tapping in prep for the helicoil?

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Here in the capital of the Philippines,Manila were you will experience the worst traffic you could ask for.20 kms in 5 hours,i think one of the best proving ground regarding the helicoil rebuild on the rav 4.It has traveled 760kms after the repair 13 days ago.

Regarding your questions.I use the stainless coils.No need to drill.I only hand tapped it slowly.ReTorqued it @58lbs+ 90°.At first im also in doubt because of negative posts regarding helicoil.But on the first day of testing the vehicle on a 3 hour snail phase notorious traffic on very hot weather.I was amazed.

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Just to inform everybody that after a year,(15,000+kms)the Helicoils still holds.Done some Rav's here and no backjobs yet.

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Well done pal, hope it serves you well for years :thumbsup::thumbsup:

Regards

Pete.

 

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