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2003 Outback wagon
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Discussion Starter · #1 ·
While installing my new water pump this evening I discovered that the bottom most hole (shown in pic) is stripped. My only peace of mind is I didn't strip it. Looks like the person I bought it from did it. My first indicator should have been the washers on the bolt that came out.

So what are my options? The motor is in the car but luckily it's the bottom most bolt and I have fairly decent access.
Automotive tire Working animal Safety glove Motor vehicle Horse tack
 

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Outback 2011 3.6R Premium (sold Jan 22)
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I have sucessfully used a helicoil for stripped water pump bolts.

The other option is that some of the water pump mounting holes are deeper than the OEM bolt is long so if this hole is one of them, you can source a longer bolt to install in that location.

Seagrass
 

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2003 Outback wagon
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Discussion Starter · #3 ·
I have sucessfully used a helicoil for stripped water pump bolts.

The other option is that some of the water pump mounting holes are deeper than the OEM bolt is long so if this hole is one of them, you can source a longer bolt to install in that location.

Seagrass
The problematic hole is one that actually goes straight through and you can see the other side on the backside of the cylinder head. I believe the bolt that I took out was an m8 x 1.0 so looks like the previous owner tried that. It held up but now that I removed it, it doesn't want to seem to tighten back up again. My friend who's helping me suggested a shorter bolt. But at this point it's all semantics. I want it to hold tight.

What are the chances she leaks without that bolt in there?
 

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Outback 2011 3.6R Premium (sold Jan 22)
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The bolt should be an M6 x 1.0 and there is a very good chance the coolant will leak out without this bolt installed.

Sounds like a helicoil or similar thread insert is what will be needed to fix the problem.

Helicoils are cheap quick and easy and create a very strong thread, much stronger than the original thread in aluminium.

Seagrass
 

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2003 Outback wagon
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Discussion Starter · #5 ·
The bolt should be an M6 x 1.0 and there is a very good chance the coolant will leak out without this bolt installed.

Sounds like a helicoil or similar thread insert is what will be needed to fix the problem.

Helicoils are cheap quick and easy and create a very strong thread, much stronger than the original thread in aluminium.

Seagrass
I assumed it would leak as well.

I won't lie, I'm a helicoil novice. Can you educate me at on what I'd need to get and do? A 101 crash course 😬
 

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Outback 2011 3.6R Premium (sold Jan 22)
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You can purchase a kit to do the job.

Basically you get a drill of the correct size which you use to drill out the current thread.

You then use the include thread tap to cut a new thread and screw the helicoil into the newly threaded hole.

The internal thread of the helicoil is 6mm x 1.0 so you simply just thread a new bolt of the correct length into the helicoil.

As you advised the current thread goes straight through to the head you may want to add a dab of medium strength loctite to the helicoil external threads before you insert it but this is not necessary.

If you search helicoil in YouTube you should find some videos of the procedure.

Seagrass
 
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2003 Outback wagon
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Discussion Starter · #7 ·
You can purchase a kit to do the job.

Basically you get a drill of the correct size which you use to drill out the current thread.

You then use the include thread tap to cut a new thread and screw the helicoil into the newly threaded hole.

The internal thread of the helicoil is 6mm x 1.0 so you simply just thread a new bolt of the correct length into the helicoil.

As you advised the current thread goes straight through to the head you may want to add a dab of medium strength loctite to the helicoil external threads before you insert it but this is not necessary.

If you search helicoil in YouTube you should find some videos of the procedure.

Seagrass
Appreciate that Seagrass!

Now I'm just very sad that I have to redo so much work. The cars timed and everything is all set. In order to do this fix I'm assuming I'll have to remove the water pump. Have you done the fix with the motor in the car?
 

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I can't recall if there is room for it, but if there is, just put a long bolt all of the way thru, and put a nylock nut on the backside.
You really need good access to do a decent job installing a threaded insert; probably best to pull the engine and put it on a stand if you have to go that route.
(edit to add) The backside nut doesn't even have to fit flush, as there really isn't much torque involved on the waterpump bolt ring (<10ft.lb IIRC). The nylock nut will stay in place even with zero torque, so just run it up nice and snug and call it good.
 

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2020 Outback Premier 2.5i
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If you don't have room for a nut to sit flush I'd helicoil it if I could get a drill in there (so that bits are straight) because it's a pretty basic operation. Since it's a through-hole you just have to watch that the insert doesn't start coming out the other side.
 

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Thanks everyone!! The problem with putting a nut on the backside is the nut will sit there but due to the area, there's no room to turn the nut.
If that's the case, you could drill out the hole with a 6 mm drill which would allow to tighten the bolt. Installing a thread insert would involve drilling an even larger hole, anyway. A 1/4" drill is much easier to come by, but it will remove a little more metal.
 

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2003 Outback wagon
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Discussion Starter · #17 ·
If the bolt hole is stripped as you said, why wouldn't the bolt just continue to turn and you hold a regular nut with an open end wrench?
I'm not 100% sure there's enough room for a regular nut to sit in that area. It's literally like a little corner where the hole comes through. It's going to be very close if a nut can actually sit there. It would have to be a very thin walled nut. As of right now the nut goes into the hole and tightens but then it stops and it has that "feeling" of "it's going to strip" the more I tighten. I'm thinking a shorter bolt may work too. Since I can tighten to a certain depth in that hole.
 

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Those sleeves you show, if they can fit over a bolt, perhaps could get you out of that corner enough to tighten up as much as you need.
For something like a water pump, you should need no more than 10ft/lbs of torque, and the specs probably call for less.
Let's go see if we can find them...
8.7 ft. lbs.
 

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2020 Outback Premier 2.5i
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The right fix is a thread insert - especially if you plan to keep the car for some time. Otherwise it is you that will have to deal with removal should it ever come to that, and that will probably be worse than assembly.
 
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