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Using a Torch

I’m about to attempt removal of the Y-pipe on a '97 Taurus GL wagon (3.0 2V “U” engine Vulcan) to replace the oil pan gasket. Along with that I’ll be replacing the front cover gasket and probably the valve cover, intake, and maybe even the head gaskets (all Felpro). I bought this car new in '98 and it’s got 205.7k miles on it now. The exhaust nuts/studs have never been disturbed. In preparation for removal, I’ve been heating up the car to temperature, letting it cool, then spraying the nuts alternately with PB Blaster and Liquid Wrench. Four days of this now with two days left before the weekend. However, I may need to resort to using a torch and I’m just wondering what precautions I would need to take to safely do that. I’ve never used a torch before on anything and using one for the first time in the engine compartment of an automobile seems kind of crazy to me, but nonetheless - people do this safely so I’m hoping someone here can enlighten me as to how to do that. I’m not even sure exactly how I might be able to even GET a torch on the firewall-side flange nuts. They’re well recessed from underneath and only one stud head is visible from the top. Maybe torch one nut from underneath and torch the other stud head from the top???

So what is the proper technique for using a torch safely (and effectively) on a car to remove fasteners???

What Kind Of Torch Are We Talking About, Here ?

This could be very difficult and /or risky, especially for an inexperienced user.


Just like shooting a gun, you MUST always consider beyond the target…ie; where else is your torch flame going ?
I can see it now ;
melted wires
melted fuel lines…and possible fire
melted gaskets
burned fingers

How big of a torch ?
oxy/aceteline ?
butane hand-held ?

Before trying a torch (a propane plumbers torch is easy), have you considered whether you can us an impact wrench? A $25 250 lb/ft impact wrench will break free a lot of stubborn nuts & bolts. The vibration helps greatly.

The other thing I suggest is simply cutting and replacing everything that isn’t on a stud.

If you can’t see whatever you’re heating up, I wouldn’t use a torch.
Are you sure you can’t get to them with some knuckles on your socket extensions?

You may need to invest in one of those small cameras that mount on a flexible ‘swan neck’ and the other side of the swan neck goes to a small hand held screen. I bought one when they first came out and that thing has paid for itself several times over in situations like you’re describing.
Also very handy for looking inside house walls when you’re doing wiring.

A borescope is actually a great idea. I use mine for all sorts of things, including checking a wall cavity out for evidence of rhodent invasion. I even used mine to take a photo of a tooth cavity. I was the first patient ever to bring a photo of the cavity in to my dentist!

Such an effort sounds dangerous for anyone, but especially dangerous for a novice. In a shop with a lift and fire extinguishers and experienced help for back up, with nomex gloves, heat shields and all manner of special tools handy the project could be taken on with likely success. But at home, working alone in the driveway with limited tools it sounds like an invitation for disaster.

Rod, your post has caused me to rethink my answer. Forget the propane torch. But do try the impact wrench and cut & replacement philosophy.

An impact wrench is an invaluable tool. I would not be without one.

That^, and - this may be obvious - but only use 6 point sockets and wrenches on rusty and stuck hardware.

If you have to cut in tight quarters a Dremel tool with a cut off disk can do wonders. You can often use it to zip a large part of a nut off so you can smack and break it with a chisel and hammer.

CSA & Ken Green:

I was told elsewhere the torch would have to be oxy/acetyline … or something with a short and hot flame. A propane torch has a bigger (and weaker) flame, apparently.


Actually, I have a compressor that would probably drive an impact wrench well enough. It’s the largest horizontal tank unit that Harbor Freight sells. Can’t remember the size, offhand. I just use it for the car tires. Haven’t bought any air tools for it yet, but this might be a good excuse. You’ve also reminded me - I’ve also got an electric impact wrench laying around that my Dad gave me as a Christmas gift a few years ago. Hasn’t been out of the box yet. It’s a Chinese unit and I just assumed it wouldn’t be usable, but maybe it’ll work. There it is … says “12V Impact Wrench” on the box.


I can get to 4 of the 6 nuts fairly easily. They are on exhaust flanges along the bottom of the car. If these break off on me I think I can grind, cut, or chisel my way to success. It’s the two nuts on the flange halfway up the firewall side of the engine that are hard to SEE, let alone get a socket on, and this may be what ultimately stops me! But maybe with the right combination of swivel, universal, extension, breaker bar, etc. it’s doable. Sometimes ANGLE is everything!

Rod Knox:

I think I’ve decided the torch is out of the question now (at least for ME). If the 6-point sockets, extensions, swivels, universals, etc. don’t do the trick, then I’ll try the electric impact wrench or invest in an air impact wrench for my compressor and/or a Dremel cutting tool.

Thanks for your help. I’ll let you know how it turns out!

Fire can be your friend or it can burn your garage down.

You have to be smart when applying heat to a vehicle. First look for possible leaking fluids that can ignite. Such as oils and grease. Look for any rubber/plastic components that can be damaged or burned by heat. Sometimes things will need to be sheilded from the heat. Welding blankets, sheet metal, or Kevlar pieces are used to protect those components. Or taking a piece of pipe clamped in ViceGrips where you can shoot the flame right on the bolt/nut will protect those components.

If you don’t try doing something you never learn.

At one point man said, “Fire! Bring back cave!”


If you have the largest horizontal tank unit that Harbor Freight sells, than you can definitely drive any air tool you can buy for as long as you need to. I love that place. They have REAL tools.

I used a torch on these things all the time years ago. For a first time user I would advise against it. Also forget the propane. oxy/acy is the only way to go

You need some quality tools and an impact wrench and you’ll be fine. Spray the rear flange nuts with a good penetrating oil. You need a 15mm semi-deep wobbly impact socket like this one:, a good stout extension (not the Pittsburgh kind that will twist before turning the socket), and an impact wrench. They’ll come right off.

I don’t think a dremel is going to do much on rusted bolts. A 4 1/2" angle grinder with a cutting disk mounted on it will cut very quickly where you can get it in.

If you can get in with a 4 1/2 die grinder, then you’d use that, of course.
If you can’t get in a particular tight spot, a dremel with a cut off disk is surprisingly effective. They have these quick change cut off disks now that are great, albeit spendy.

I too have used a dremel in tight places. I can testify to their effectiveness. Not as fast as a grinder with a disc, but one heck of a lot better than a hacksaw!

C’mon guys, there is something inherently masculine about using oxy-acetylene fire wrenches! The risk of explosion, consequential damage from the flame, the bright light, molten metal down your sleeve…. I had a buddy who would fire his up just to light a cigarette!

Nothing alarmed me more than one friend who bought his set up on a budget. When I spotted he had no flashback arrestors, I was outta there! I like danger as much as the next guy but there’s a limit.

Propane is almost useless IMO. MAPP gas is better in almost every way and the cost difference isn’t even worth discussing. Consider that the lowest level of flame wrench if you’re operating on budget.

Heat is best (and lots of it) but if the conditions aren’t right, then it’s liquid penetrant and torque followed by mechanical destruction as a last resort in my play book…

MAPP gas burns hotter than regular propane because it has acetyline added to it, but if one is just trying to heat something up to expand it, I’m not sure that’s a good thing. I suppose it’s just preference. Having done some plumbing, a have propane handy.

But the truth is that I agree that using open flames of any kind is a risk to be avoided unless absolutely necessary.

I have an oxy-acetyline torch that is really nice but you have to be careful with it because it gets everything hot and bothered.

This may be a little overkill but it does work like a charm:
Last year I bought an all-in-one plasma cutter that has a small compressor in its box. It is super convenient since it is small and portable. It isn’t a super high power flavor but it works great on sheet metal. I use it to make panels on my vintage cars.
Its heat is highly directive. I can cut sheetmetal with a wooden straight edge without lighting the wood on fire so that gave the the idea to use it to get hardware off.
To get a stripped nut off, you can slice a deep groove into the nut and then break the thing loose (or just break it in half) with a punch.