Using a Torch

Colt Hero

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#1
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???
 

billr

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#2
I wouldn't use a torch in there. I can (almost) always find a way to cut a fastener away with grinder, chisel, saw, drill, etc. But, I'm not there... can't see or feel what you are up against. And if I couldn't find a way to cut, then considering all the other work you have to do, I would probably pull the whole engine/cradle assembly out the bottom. Yeah, may have to neatly cut exhaust piping, suitable for welding back up after all those rusted joints are separated, to get the engine out.
 
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#3
Generally speaking....remove nearby flammable items like plug wires, create a heat shield for things like a CV boot or a plastic valve cover. Don't place too much trust in a heat shield, it can hide the fact that damage is happening behind it. Use a smaller tip for a smaller flame, and keep the Ox pressure high enough to keep the flame short. Have water spray bottle and wet towels nearby. Wet towels can also be a good heat shield...if the towel starts to burn a little, wet it again. And have a helper nearby to watch for "unintended ignition" and to hand the torch to so you don't have to relight it a million times, and so you can get your wrench on the hot bolt IMMEDIATELY.
 
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#4
Do not use one of the propane small tank type torches they put out too big a flame and will take forever to get cherry red. Everyone here is talking about a Oxy/acetylene torch setup with a brazing tip to give you the smallest but hottest flame. My .02
 
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#5
I would bet (and hope for your sake) that given the preparation and patience you have used the bolts will loosen for you without heat. If not, I agree with all the good points above.
 

Colt Hero

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#6
billr:

I'm hoping I won't have to resort to the torch, too. Four of the nuts are on flanges along the underside of the car, so if THOSE break, I've got enough clearance to drill, saw, grind, etc. like you mention. But even if I get these nuts off, it's going to be those firewall-side nuts on that flange located about halfway up the firewall that could ultimately stop me. Not easy to get a drill, saw, or grinder in there, I don't believe.

Danica:

Thank you for the safety tips! I think I can do those things. I'm a pretty careful person in everything I do.

dabunk:

Thanks for that clarification. Smallest, hottest flame, oxy/acetylene, and NOT propane with the big flame. Got it. Sounds like something I'd have to have a shop do, though.

JackC:

I'm hopin' they break free, too! The only reason I'm using this much patience is we expanded the fleet to three cars a little less than 2 years ago (2011 Equinox V6 joined 2002 Impala and this Taurus) and because of that I don't have to hurry my repairs over a weekend or long weekend. One time I replaced the intake gaskets on the Impala and it took me almost 3 weeks! We went down to ONE car during that time and the wife wasn't very happy (even though I bent over backwards to make sure it didn't affect HER schedule in the least ... I switched to 2nd shift while I worked on the car during the day).

Thanks for all the input!
 
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#7
Best of luck to you.

Nothing worse than a broken bolt, stud, etc.

Got to ruin your day.

When it happens I always envision how easy it would have been if only the part were out of the car and on the bench. Then I swear at the engineers that make things seemingly almost impossible to work upon.
 

billr

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#8
A while back I had to do R&R on the alternator in a '98 Taurus with the 3.0 V-6. It turned out that the recommended method there was to unfasten the engine cradle and drop the whole assembly down an inch or so. It was surprisingly easy, just two easy-to-reach screws on each side of the cradle (I only had to loosen one side, at that), and just lowering the engine that much may make things easier for you.
 
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#9
Cold rolled steel bolts in aluminum? Broke the very first rule of employing dissimilar metals, electrolysis fuses these two materials together.

Can have fond memories of the past when far more common to break a wrench than a bolt, cars back then were made to be repaired. But that is long ago history.

So what use to be a five minute job can take all day, carefully drilling out the old broken bolt, and retapping the holes. Can sometimes get by with increasing the bolt size by a millimeter.

I believe the 3.0L was imported from Japan, so may not be much of a problem, the 3.8 L was sure a problem, never ever want to work on a 3.8 L again. Life is too short. Heat wouldn't even work when aluminum fuses to steel.
 

Colt Hero

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#10
JackC:

Thanks! I'm not a mechanic and I don't even have a garage, but at least I have a driveway to work on. When I was growing up in MA I used to do everything in the STREET! No way I would ever do THAT again! Speaking of cars nowadays being so hard to work on (due to lack of space and bad angles), I think back to the '68 Valiant my Aunt had when I was a kid. You could probably stand inside the engine compartment while you were working on it! Plenty of airspace in there!

billr:

As I mentioned immediately above, I'm kind of limited as to what I can do in terms of repairs. But what you mention sounds do-able. I'll keep that in mind if I cannot get at the passenger-side firewall-side flange nut. That's the one that's going to stop me.

NickD:

My 3.0L Taurus engine might've been imported from Japan??? First I've ever heard of that! Anybody else want to comment on that? Could this be true??


I sprayed the bolts again this morning, but with a new can of Liquid Wrench. Big difference, as the fluid came out more like PB Blaster: more sudsy and it stuck to the fastener better. I think the can said it was an "improved formula". The 'old' can I had lying around sprayed out like water. No 'body' to the fluid at all! One more spray tonight after work then I'll try to break 'em free tomorrow morning!
 
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#11
Think you are talking about where the wye pipe fastens to the exhaust manifolds. Are they using studs or bolts? With studs after a bit of try if frozen tight, I just use a nut breaker, run a die on the threads and use brass nuts for the next time. If there is a next time.

With bolts, the only solution I know of is using an acetylene torch, at the exhaust manifold outlet, shouldn't be any fuel or electrical lines near it, have to heat that area red hot to remove the damned things.

How is this for a problem, on my 454 CID and Supra 3 L turbo, have problems with the exhaust manifold bolts to head coming loose. This beats the hell out of me. Normally rusted in tight. But these exhaust manifolds really get red hot, least I know where my gas money is going to.
 

Colt Hero

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#12
S-T-E-E-E-R-I-K-E ONE !!

I was able to get the nuts off the studs at the front of the car (exhaust manifold flange), but the downstream nuts (past the cat) both stripped on me. And the third set of nuts - recessed up the firewall side - I couldn't even get the socket on! I think my deep socket is TOO deep. I couldn't even fit it over the stud properly from the top and, even if I had, there wasn't any room left against that stupid fireshield for the ratchet or breaker bar to attach! Seems like a need a 'shallow' deep socket (and maybe a universal to try again from the top, and an even crazier combination from the bottom : maybe two 6" extensions, a wobbler, a universal, etc. It's a narrow channel from underneath and the nut sits at a weird angle ... the other nut - forget it .... I doubt I can get onto THAT one from underneath)?

So how do I remove the stripped nuts now? A Dremel, a Harbor Fake equivalent, a nut breaker?? And what precautions do I need to take using a rotary tool with a cutting wheel on a nut bathed in flammable liquids (oil, Liquid Wrench, PB Blaster)? Is this a fire hazard?
 
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#13
As far as getting the striped nut off, there are external easy out sockets for this situation. They work great. Got me out a few bad issues. Bought mine at Sears. They are probably sold at a lot of places. But of course if you need a deep well, then these external easy out sockets that I have are shallow well and would not work. They do have deep well external easy out sockets for that issue. These external easy outs also have a hex on the end so that you can use a box end wrench on them. Just remember when using a box end wrench or socket on rusted nuts, always use a six point socket or box end wrench.
 

Colt Hero

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#14
I'm thinking of something less expensive to get those two nuts off. Maybe Harbor Fake's $25 Dremel knock-off?

http://www.harborfreight.com/variable-speed-rotary-tool-kit-68696.html

Reviews are good (if you can believe them). Looks like the attachments aren't that great, but Dremel wheels work with this thing, so maybe that's the way to go?

============
Just found this on the Sears site ($26.99) but no deep sockets:

http://www.sears.com/shc/s/p_10153_12605_00952166000P?vName=Tools&cName=HandTools&sName=Tap%20&%20Dies%20&%20Setsmv=rr

... or this "Grip Tite" nut/bolt removed ($58.49) which DOES have deep sockets:

http://www.sears.com/grip-tite-17-pc-super-sockets-rounded-bolt-remover-metric/p-00910325000P

============

But do I NEED a deep socket at this point? All I need is something to fit over the rounded nut that will then fit into a larger socket and cut into it as I remove it.
 
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#15
For rusted nuts, found a Dremmel with a metal cutting blade very useful, can really get into tight places. Darn blades are over a buck fifty each, and takes one per nut with nothing left of it. After the cut spread the nut with a chisel or a sharpened impact hammer bit, then it comes off with my fingers.

Had to remove the cat on my 88 Supra turbo, was using bolts. With the Dremmel, cut the heads off, soaked the ends in pure hydrochloric acid. Then a blast of PB blaster. Was able to remove the remaining headless bolts without two much effort with a small pair of visegrips without damaging the welded in nuts.

A guy sure needs a complete set of both metric and English dies and taps.