jb weld

[kramlavud]

Today I started my son's 95 Nissan Altima and heard an exhaust leak. Looked under the car and saw the cat convertor's O2 sensor dangling. Seems it just blew out, as all of the threads on the sensor are gone. So I cleaned the mating areas and applied JB Weld. Car will sit for about 15 hours before he uses it again. Anyone care to guess how long this might last; an hour, day, week, or?

regards,
Mark

[Southern]

I'm not sure of the max. temp rating of JBWeld, but if it can withstand the high temperatures I would give it a good year unless the O2 sensor goes out.

[pete911]

A Few hours.

[mctwin2kman]

I put JB Weld on my exhaust manifold and it lasted about 15 minutes before it was totally burned off! Also smells like crap when burning. I was just trying it as it is rated to over 600 degrees but apparantly not much past that. I thought it would last a little longer but was way wrong. There are other exhaust type fix it materials out there that are rated much higher.

I'm surprised that it lasted 15 minutes. To loosen J B Weld, you use a torch, so it can't take too much heat.

It wouldn't cost much to get a muffler shop to weld in a new bung and then weld over the old hole.

Good luck,

[manny]

You could also try re-tapping the existing bung.
Providing you have an 18 mm tap.
Still need a new O2 sensor though.

[mpolli]

Kramlavud,

I admire your spirit. However, I don't think it will last long. This reminds me of some of my (many) ill-fated repair attempts. It seems the ones that are flawed will fail almost immediately. If you get a week out of it I think you should be very proud. I hope you will let us all know how long it actualy lasted. I think Manny's or Larry's advice is the best. I don't think any type of repair goop will last in this application no matter what it is.

Mike

[mctwin2kman]

I tried repair goup and exhaust tape type materials and all failed. My solution that worked was to braze the O2 onto the bung on mine because I needed to keep the O2 in there and that was my only option at the time. No braze rod in our shop at the time so I used Coat Hanger(a wire one), still holding up and no leaks for the last 9 months!

[pberku]

Wall-Mart, and probably other places sell an epoxy glue that you knead with your hands like dough, before applying.

Its cylindrical in shape, about 4" long and 1/2 " diameter. You cut as nuch as you need, and then as I said you knead and apply.

This stuff will withstand more than 500F, and will set in 20 Min, Its amazing stuff, and will last forever.


Phil

[Jim Anderson]

I was replacing an exhaust manifold and used some of that reddish colored high temperature silicone RTV gasket stuff. After I was finished I thought I would try an experiment and find out what it would take to burn that stuff and put a dab on the exhaust manifold. The experiment failed, it was still there months later. The only disclaimer to the validity of this experiment is that it was on a diesel, they don't get as hot.

[manny]

Originally Posted by pberku

Wall-Mart, and probably other places sell an epoxy glue that you knead with your hands like dough, before applying.
Its cylindrical in shape, about 4" long and 1/2 " diameter. You cut as nuch as you need, and then as I said you knead and apply.
This stuff will withstand more than 500F, and will set in 20 Min, Its amazing stuff, and will last forever.
Phil

That would be called JB WELD.
500 deg. F is about 1/2 the temperature that the oxygen sensor is subjected to.

[pberku]

No. Its definitely not JB Weld. The 500F was memory, could have been much higher. It's recommended for mufflers, catalytic converters, radiators, etc., so it can definitely withstand any temperatures or pressures that the oxygen sensor is subjected to.

It has the consistency of Mastic or putty with an inner and outer core. The inner core is black, and the outer core is greyish. You knead it in order to intermix the two layers. You then have a window of 4 Min to apply it. After that it starts to set and is cured 20 Min. It can even set underwater, and is impervious to all chemicals and fluids found in a car.

Its available at the Wall-Mart automotive section, but I am sure also at most hardware store. Sorry I don't remember the name, but you should be able to find it easaly by my description.

By the way, this stuff has never failed me, and it has always worked where JB Weld failed. Just make sure that it has a relatively clean surface to stick to, and that you knead it well.


Phil

[manny]

Sounds like you're describing " Liquid Metal ", ot " Tech-Steel " ( black core/grey layer on the outside ).
I have used it to do some minor patching on an aluminum casting, that is not subjected to any kind of heat or pressure.
The proper repairs for this situation have been described above.

[pberku]

Both of the names that you mention, Liquid Metal ", and " Tech-Steel, sound familiar. I am sure it was one of them, more probably Tech-Steel. I did use it for both, Radiator repair, (High pressure), as well as Catalytic converter repair (Very High Temperature). It held permanently in both cases.

I also used it for various other repairs around the car, many vibration sensitive areas. Never failed yet. I have no doubt that the Oxygen Sensor can be repaired with this epoxy very easily and permanently


Phil

[kramlavud]

Day 2 and still holding.
Thanks to all for your thoughts.
I will post every few days until it fails, unless of course no one is interested.

regards,

Mark