Seized exhaust manifold nut

[Lily the Pink]

Having released 7 of the exhaust manifold/header nuts (Porsche 944), I am left with just one which won't budge. It is tucked in fairly tight to one of the pipes; too tight to get a ring spanner or socket on, and an open ended spanner only results in rounding off the nut's corners. I have sprayed it liberally with WD40 over the last few days. I think my next option is to grind down the edges of a 13mm ring spanner until it is thin enough to fit - but of course that will weaken the spanner. If that doesn't work then I shall have to work out how to get a flame down there to heat it up. But before I do any of that - does anyone have any experience of Wurth Rost Off Ice (or their Blue Ice, or any alternative products) ?

Or any other ideas ?

[Boosted LS1]

You need something that's a tight fit.

Also have you tried hitting a far smaller socket onto the nut first? Not to engage the nut but to try and break the seal between the nut and stud. if you break that seal the nut or even the stud will unscrew.

[paintman]

Grind the spanner - I've done that to a few of mine & it's usually the smaller sizes too!

Loctite's Freeze and Release has worked for me.

[GreenV8S]

Lily the Pink said:

I have sprayed it liberally with WD40 over the last few days.

Spraying it with penetrating oil would have been more useful.

Any chance of getting a grinder/dremel in there? Presumably you'd be looking to replace the stud+nut anyway.

[littleredrooster]

Lily the Pink said:

I have sprayed it liberally with WD40 over the last few days....

Unfortunately, that's the main part of your problem, IMO. WD40 is fekkin useless as a penetrating/release oil; Plus Gas would have been much more effective.
Can you get some heat in there? Blowtorch or proper hot-air gun? And surely even a short ring-spanner or socket would fit and be infinitely better than the Devils own open-ender?

[CrutyRammers]

Can you get hold of the end of the stud? I've taken a few out using mole grips over the years, ignore the nut, take the whole stud out. Or weld another nut onto the end of the stud and use that.
Another idea is a cold chisel. You can split the nut, or sometimes hammer it around and get it loose.

[E-bmw]

As others have said above O/E spanners aren't worth a w@nk on tight nuts. OOOO EERRR MISSUS!

If you can't get a ring or socket on you will definitely want heat as your first alternative, but will still need a socket or ring spanner on it.

Have you tried a proper offset ring spanner.

Or even a swivel head spanner?

Try asking around those in your circle who do their own spannering, I personally find I have at least 6 of all the general sizes in pretty much every format known to man.

eg. an e36 6-pot M3 exhaust manifold will need 11mm socket, with/without wobble bar, a normal ring, a ratchet spanner, a deep offset ring spanner and a swivel head spanner to make good progress & even then it takes a couple of hours to do both manifolds.

[steveo3002]

cant help but think a ring or socket would fit ...doubt it was assembled with an open end spanner , might need a certain combo but look into it

[LordLoveLength]

Thin Stilson would work - won’t slip. Mole grips can slip if the nut is rounded.

[Lily the Pink]

Thanks all, got the problem nut loose with a good dose of penetrating oil and a ground-down ring spanner; needed to reduce both its thickness and its overall (outside) diameter in order to get it on the nut - see the narrow gap between nut and exhaust ...



Getting all back together will be fun; no chance of getting a torque wrench on it.

[GreenV8S]

Lily the Pink said:

Getting all back together will be fun; no chance of getting a torque wrench on it.

Coppaslip to help the poor unfortunate who has to take it off next time, an obstruction spanner and careful calculation of leverage should do the trick. Do you have trouble with the nuts working loose? I have the same problem on the V8S. They studs are very short, which means there's very little stretch to cope with thermal expansion. If you're got room to get a slightly longer stud with a spacer under the nut, it can help with that - but makes the access even tighter, of course.

[ShampooEfficient]

Replace it with a stainless nut and lots of coppaslip. I wonder if there's space for a crows foot to do the final tighten.

[E-bmw]

ShampooEfficient said:

Replace it with a stainless nut and lots of coppaslip. I wonder if there's space for a crows foot to do the final tighten.

Don't do this, St/Steel does NOT cope well with high heat cycles & almost certainly will strip the stud on removal.

[CrutyRammers]

E-bmw said:

Don't do this, St/Steel does NOT cope well with high heat cycles & almost certainly will strip the stud on removal.

Aye, older cars used brass nuts in this application. They don't stick so badly but are easier to round off, so it's swings and roundabouts. I've generally settled on copper greasing the end of the stud into the block, so if all else fails, that will come out, even if the nut is completely rusted on.

[VanDiesel99]

Before you put it all back together

Angle Grind most of the Handle off a cheap 3/8 Ratchet, a damn handy tool in a tight space

Buy yourself a Ratchet Spanner or set of same, if you think you'll get one in there (I tend not to use mine much coz they're invariably too big, but these can also be 'cut off').


Consider whether a Deep socket or a combination of Adapters/Reducers will provide improved access. For some applications on my motor I cobble together an inch or so of 'Socket Extension' using a 3/8 to 1/2 and 1/2 to 3/8 converter

Have a practice run in a free space with your Torque Wrench if you're keen to get the Torque about right, then see how that feels with the tooling you can get down there.. replicate.
(not that I've ever Torque'd exhaust manifold bolts)

Attach a large piece of brightly coloured tape to the spanners you're using, much easier to find if you drop em

[GreenV8S]

VanDiesel99 said:

Attach a large piece of brightly coloured tape to the spanners you're using, much easier to find if you drop em

Try string instead.

[sospan]

Ground down ring spanner. I picked up several rejects from scrap that came into our works. Rejects from the forge with one good end, the other knackered. When I need to modify a spanner to fit it is one of these that hets the work. Car boot sales, auctions car events and jumbles are good places to pick up old spanners.

[rxe]

Old thread, but it’s a good example of why some tools are more expensive than others. Put a Snapon 13 mm and a Halfords Pro 13 mm next to each other - the Halfords one is bigger - thicker metal, less well machined, won’t get into tight spaces. If you the add the Halfords ratchet spanners, they’re bigger again, and the Halfords flex head ratchet spanners look like they’re made of playdoh in comparison.

Note that on a lot of Alfa 105 engines, the exhaust nuts were actually 12mm to aid access. Should these actually be 13mm?

[Chris32345]

rxe said:

Old thread, but it’s a good example of why some tools are more expensive than others. Put a Snapon 13 mm and a Halfords Pro 13 mm next to each other - the Halfords one is bigger - thicker metal, less well machined, won’t get into tight spaces. If you the add the Halfords ratchet spanners, they’re bigger again, and the Halfords flex head ratchet spanners look like they’re made of playdoh in comparison.

Note that on a lot of Alfa 105 engines, the exhaust nuts were actually 12mm to aid access. Should these actually be 13mm?

The Halfords spanners don't require a mortgage to buy and you could grind down two sets and still have spent less money then the snap off ones
Nobody's outside of a professional environment should buy snap on


And even then it's debateable how good they are for there money plenty of other tool's as good quality for less price

[markcoznottz]

Manifold studs are a five minute job with the right tools. Rothenberger type torch with map gas, heat to cherry red, squirt with room temp water, job done. Induction heaters can do similar, but still aren’t cheap, especially for the diy spannerists.