Advice for stripped threads upstream oxygen sensor exhaust manifold

**Arlen Holder** · August 2nd 18, 04:31 AM posted to alt.home.repair,rec.autos.tech

**Paul in Houston TX[_2_]** · August 2nd 18, 05:25 AM posted to alt.home.repair,rec.autos.tech

Arlen Holder wrote:
> Car is just bought by a kid just learning to drive (he's 16).
> 2004 Mitsubishi Lancer ES
>
> Neighbors asked me to teach him how to replace the oxygen sensor (due to
> emissions code).
>
> The threads were stripped and "filled" with some kind of hardened "metal
> paste".
>
> The new part is a Denso 234-4739 (marked 485000-4060, 07U05)
> The old part is a Denso (marked 234000, 8643, 07E23)
>
> What would you suggest?
> - Tap the threads? (22mm hex nut)
> - New exhaust manifold?

IF it were my car and IF the manifold is steel, I would remove the manifold,
then remove the square nut, and weld or braze in a thin-ish nut of appropriate
thread size.
If no thin-ish nut is available then make one with the dremel.
The sensor needs to be in the flame and also have good thermal conductivity to
the manifold.

**Arlen Holder** · August 2nd 18, 06:36 AM posted to alt.home.repair,rec.autos.tech

On 1 Aug 2018 21:25:57 GMT, Paul in Houston TX wrote:

> IF it were my car and IF the manifold is steel, I would remove the manifold,
> then remove the square nut, and weld or braze in a thin-ish nut of appropriate
> thread size.
> If no thin-ish nut is available then make one with the dremel.
> The sensor needs to be in the flame and also have good thermal conductivity to
> the manifold.

I had not thought of putting a new nut on.
I'll look in the morning to see if the nut is the only threads.
I'm sure the sensor has to be "in" the stream of hot vapors.

It seems to be cast iron. Aren't they all that way?
(It's rusty.)

**Bob F** · August 2nd 18, 05:41 AM posted to alt.home.repair,rec.autos.tech

On 8/1/2018 8:31 PM, Arlen Holder wrote:
> Car is just bought by a kid just learning to drive (he's 16).
> 2004 Mitsubishi Lancer ES
>
> Neighbors asked me to teach him how to replace the oxygen sensor (due to
> emissions code).
>
> The threads were stripped and "filled" with some kind of hardened "metal
> paste".
>
> The new part is a Denso 234-4739 (marked 485000-4060, 07U05)
> The old part is a Denso (marked 234000, 8643, 07E23)
>
> What would you suggest?
> - Tap the threads? (22mm hex nut)
> - New exhaust manifold?
>
> http://www.bild.me/bild.php?file=3234632o2sensor01.jpg
> http://www.bild.me/bild.php?file=8064061o2sensor02.jpg
> http://www.bild.me/bild.php?file=6399144o2sensor03.jpg
> http://www.bild.me/bild.php?file=1574232o2sensor04.jpg
> http://www.bild.me/bild.php?file=9418974o2sensor05.jpg
> http://www.bild.me/bild.php?file=4183674o2sensor06.jpg
> http://www.bild.me/bild.php?file=5856176o2sensor07.jpg
> http://www.bild.me/bild.php?file=3486734o2sensor08.jpg
> http://www.bild.me/bild.php?file=9694112o2sensor09.jpg
> http://www.bild.me/bild.php?file=5019152o2sensor10.jpg
>
I'm no expert on this particular situation, but perhaps a helicoil would
solve it easily.

**Arlen Holder** · August 2nd 18, 06:37 AM posted to alt.home.repair,rec.autos.tech

On 1 Aug 2018 21:41:29 GMT, Bob F wrote:

> I'm no expert on this particular situation, but perhaps a helicoil would
> solve it easily.

I guess it can't hurt.
I can contact Denso to figure out the thread pitch for their O2 sensors.

I was thinking of cleaning up the threads, but they look really bad.
How on earth can ANYONE do that to a bunch of threads?

What did they do?
It's not even hard to get to ... it's right there ... in front.

**Scott Dorsey** · August 2nd 18, 03:10 PM posted to alt.home.repair,rec.autos.tech

Arlen Holder > wrote:
>On 1 Aug 2018 21:41:29 GMT, Bob F wrote:
>
>> I'm no expert on this particular situation, but perhaps a helicoil would
>> solve it easily.
>
>I guess it can't hurt.
>I can contact Denso to figure out the thread pitch for their O2 sensors.

You have it out, measure the pitch.
The helicoil is probably the easiest solution and I am generally a fan of
the things.

>I was thinking of cleaning up the threads, but they look really bad.
>How on earth can ANYONE do that to a bunch of threads?
>
>What did they do?

They tried to remove a stuck oxygen sensor cold, maybe without even using
a proper penetrating oil, and they just put force on it until it deformed
and eventually tore itself out.

>It's not even hard to get to ... it's right there ... in front.

Are you absolutely sure it's the problem also?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

**Arlen Holder** · August 2nd 18, 03:55 PM posted to alt.home.repair,rec.autos.tech

On 2 Aug 2018 07:10:52 GMT, Scott Dorsey wrote:

> You have it out, measure the pitch.
From research since yesterday, all oxygen sensors seem to be M18x1.5 so I'm
clear on that.

> The helicoil is probably the easiest solution and I am generally a fan of
> the things.

Thanks. I think my current plan is:
a. Pick up a thread chaser & try that
b. If that can'd be found, consider a junkyard exhaust manifold
c. If that fails, consider a new one
d. If that's too pricey, consider a helicoil kit (but they're pricey too)
e. Maybe even consider drilling and then inserting a threaded bung

> They tried to remove a stuck oxygen sensor cold, maybe without even using
> a proper penetrating oil, and they just put force on it until it deformed
> and eventually tore itself out.

Jesus. Who would do that. I have never stripped a thread coming out!
(I've stripped threads going in, but never coming out.)

> Are you absolutely sure it's the problem also?

It is now.

**rbowman** · August 2nd 18, 06:26 AM posted to alt.home.repair,rec.autos.tech

On 08/01/2018 09:31 PM, Arlen Holder wrote:
> What would you suggest?
> - Tap the threads? (22mm hex nut)
> - New exhaust manifold?

Back to your friendly Loctite dealer for the Form-A-Thread kit? Trip to
a junkyard for a new manifold if replacing it isn't too painful? Helicoils?

**Arlen Holder** · August 2nd 18, 06:39 AM posted to alt.home.repair,rec.autos.tech

On 1 Aug 2018 22:26:00 GMT, rbowman wrote:

> Back to your friendly Loctite dealer for the Form-A-Thread kit? Trip to
> a junkyard for a new manifold if replacing it isn't too painful? Helicoils?

Seems to me the choices are...
a. New or used manifold (if it's not too hard to replace)
b. Drill it out and helicoil it (nothing to lose really)
c. Clean it up with a tap (I don't have the tap, which won't be cheap)
d. Shove it in there with epoxy (I hate that idea so I don't want to)

**Arlen Holder** · August 2nd 18, 07:18 AM posted to alt.home.repair,rec.autos.tech

On 2 Aug 2018 05:39:22 GMT, Arlen Holder wrote:

> b. Drill it out and helicoil it (nothing to lose really)

Googling, I'm not yet sure a helicoil will work on a through hole.

I think all lambda sensors are 18x1.5 (I'm not sure, but people said that
on the net). Some say it's the same thread as for spark plugs.

If it's the same as for spark plugs, this might work, maybe?
https://shop.advanceautoparts.com/p/...2002/5014964-P

Napa seems to sell a thread chaser for spark plugs, if it's the same thread
as spark plugs...
https://www.napaonline.com/en/p/SER730

This bung might be able to be welded on by a shop if the threads are right:
https://www.diyautotune.com/product/...plug-kit-3735/

The manifold is almost five hundred bucks
https://www.carid.com/eastern-cataly...46&url=4700416

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