Safe to use blowtorch near oil pan and catalytic converter?

Have to remove an 02 sensor just behind the catalytic converter. Might need to use a propane type torch as it is rusted to hell. The oil pan is right there (covered in oil from the valve cover leak) and I read fuel or fumes go through the cat. So is there any chance of starting a fire?

While I wouldn’t expect gasoline in the catalytic converter to be a problem oil dripping off the engine could be and lying on the ground under an automobile holding a flame near various flammable materials is not a safe place to be.

Have you attempted to loosen the sensor? When O2 sensors are difficult to remove I knock the top off and use either a short 6 point socket or a combination wrench to get it out. Trying to work over the top of the sensor is a real pain. But be aware that if you are unable to remove the sensor with the top off and must drive to a shop the hot exhaust out of the broken sensor will be acting like a blow torch on the floor, wires, etc.

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This is something that an independent muffler shop could do at a reasonable price and not put you at risk for injury.

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The jack I was using only went up so high, so had no real leverage to give it some torque. It is rusted and from what I did try seems like it was slipping with the 02 socket. Got a new jack today so will try in a few days. Now I read that the 02 sensor sockets are really no good, which I just bought a set of:cry:

Thinking a 22mm long socket would work if I just cut the wire without removing any of the body on the sensor? If I just cut the wire and could not get it off it would be safe to drive to a shop?

Ive seen a lot of 02 sensor videos on Youtube and people using torches then thinking of all the flammable oils, solvents and fumes and wondering how big of an issue it is and just for other areas of the car too, have yet to hear someone using a torch mention flammables.

An oxygen sensor socket is useful when installing a new sensor but can break when trying to remove an old sensor. A co-worker once returned my O2 sensor socket to me broken with the comment that the tool man would replace it next week, not a positive experience.

When accessible I usually use a 7/8 open-end wrench or box wrench to loosen an old oxygen sensor.

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Makes sense, I forgot I have to put a new one in:laughing:

Just looked and I only have a short 3/4 22mm socket. Will look into some 7/8 and 22mm wrenches.

Would you recommend a 6 or 12 point wrench?

A 12 point box wench should be sufficient, an open end wrench has only two sides but will work sometimes.

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I have found an old fashioned pipe wrench can work if you have the room. Even worked After I mostly rounded an O2 sensor off. The more you. Pull the tighter a pipe wrench will get.

A lot depends on where you live. Case in point- my brother lives in the Denver area. I took off his 15 year old bumper with a crescent wrench (all he had) with no difficulty whatsoever. Where I live, you’d need penetrating oils, time, heat and/or pneumatic tools to break the fasteners free.

Around here, you’d round off most old O2 sensors in seconds using an open end wrench, A 12pt box end wrench would take slightly longer. Here, you cut the wire and use a deep 6pt socket and the longest extension you can fit. Heat and/or penetrating oils may still be required.

The O2 socket or box end wrench is only for installing the new sensor…

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You aren’t working on this while the car is only supported by a jack, are you?:open_mouth:


When I had trouble trying to remove O2 sensors from cold exhaust, I started the engine and let it make pipes hot, it was much easier to make old sensors budge, even with box end wrench.


You might try the Great Neck/oxygen sensor wrench from Autozone and soak the sensor with penetrating oil. This wrench has a long enough handle or you can add an extension pipe to it for added torque. Good luck.

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How about a bonfire? Tell your next-of-kin to let us know how it turned out.

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Illinois here. Lots of road salt and rust.

It seems like knocking/cutting the top of the sensor off and then using an ordinary socket/ratchet would be the easiest method. If you want to preserve the sensor then maybe there’s an impact socket available tall enough to do it.

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There are times when heat is required to do a repair.

All you need to do is use your brain.

First, check for any flammable material in the area.

In your case, there’s oil on the oil pan.

Take some brake parts cleaner and wash the oil off the oil pan.

You can’t damage the cat.

One trick when using heat in close places is, buy one of those aluminum roasting pans from the grocery store.

These can be bent into almost any shape to protect components from the heat.

A propane torch is pretty safe if you’re careful.



Thanks, I have jack stands with the metal bar that goes in the side (extra piece of mind). I did fit the stands on the frame support right below the dash with them at their lowest height. The jack barely let me fit, though I forgot I could use some wood on top of the jack to get extra height. But already got the Harbor Freight 3 ton (which is insanely heavy to have to carry to the parking lot).

I had the socket on the 02 sensor but had rust falling in my face and could feel the car move slightly and all I had was a small piece of wood by the back tire. I could just imaging the car going forward knocking the jack stands forward and the engine crushing me. So, I said the hell with it Ill get a new jack and some wheel chocks. Plus next time I will put some wood under the front tires, so that should be foolproof.

I did have the parking brake on too which I just remembered to do last minute.

Why not call a muffler shop and get a ball park price to remove and replace ? It might be cheap enough for you.

Thanks, the roasting pan is a great idea.

I was going under there anyway to do an oil change and the sensor is right there plus I already have the sensors, so might as well try it. Thanks