astra oil change: sheered plug?

Hello,

I crawled under the (1.4 petrol, 56 plate) Astra to unscrew the sump plug to do an oil change. The sump plug requires a T40 IIRC, but as I started to turn it, it felt as if the socket was turning but the plug was not. Can you get cam out/sheering of the torx fitting? Perhaps it has got brittle/corroded and failed that way?

Partly because I was getting a bad feeling about this and partly because I was on my drive and the weather was getting worse, I stopped at this point.

What is the best way to proceed with this? Should I use plusgas in case the plug has seized or been over tightened? I figure the less force required to turn it the better. What if the internal "star" of the torx socket has been damaged? Would you use mole grips or would you try to hammer a larger size into the hole, or something different? I'm hoping you won't tell me to drill it!

Thanks, Stephen.

Reply to
Stephen
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First buy a new plug, check that it is actually t40 (it might be 45 ! ) I can't remember offhand which size it is. Assuming you are right and it is a

40 and the teeth in the hole have torn off, then you need to grip the outer edge to undo it, IIRC the plug is raised slightly from the sump and you should be able to get a pair of stilsons on to undo it (or big mole grips) Best not to hammer at it as the sump is thin steel. Other methods to undo it would include welding something to it in order to turn it.
Reply to
Mrcheerful

Agreed. Although Stillsons have asymmetric teeth, theoretically better than the Mole symmetric ones, I usually find Moles more effective especially if you are gripping over a narrow band rather than a full "pipe". The trick is to tighten up the screw until you can only *just* get the Moles to close. At this point you should have deformed the sacrificial part so that the Mole teeth have a very positive engagement. You might even get away without buying a new plug.

Reply to
newshound

Thank you. I have heard it suggested that you should replace the plug whenever you do an oil change on any make/model of car, but I must confess, I never have. Perhaps changing the washer is a good idea but if the plug is sound, I've never seen the point of changing it but that was until now.

I've never seen an oil plug with torx fitting before. *If* they are susceptible to having the teeth disintegrate, then I think replacing the plug annually is a good idea. However, I think that perhaps the torx failed due to abuse rather than age? The dealer said perhaps the previous owner used an Allen key rather than torx! I wondered whether the teeth would snap off if over tightened with the proper Torx bit?

Whatever caused it, your suggestion of using mole grips was a great idea that I should have thought of but hadn't! They worked perfectly. I used a torque wrench to tighten the new one. Actually my 3/8" torque wrench doesn't go as low as the 10Nm recommended by Haynes, so it is slightly tighter than it should be, but only just.

Thanks for the warning about not hammering the sump. I hadn't realised the sump was so thin and easily damaged.

The welding something on is a good idea but I don't have a welder and have never welded. Perhaps I should buy a cheap one from aldi next time they are on sale and learn how to do it? It must be a useful skill for so many other jobs too.

I've noticed my ramps are rusting. I'll have to wire brush and repaint them one day. OTOH it is only cosmetic, so perhaps I should not be so fussy and save myself a job. I can't see how the water got under the paint to start them rusting as they are kept in the garage and only brought out once a year in the summer to do an oil change.

Haynes suggests changing the oil every 9000 miles or 6 months. Hidden away it says this is half of the manufacturer's interval. Wasn't there something on here before saying that changing too often was bad? I think I will stick with 18k or 12 months.

Curiously the Haynes book does not mention T40 bits on the sump and claims that it is a normal hex bolt and shows a photo of a hex bolt too. I've noticed it is wrong about the cabin filter as well: it says remove three screws but I found two torx bolts securing mine.

The pollen filter seemed to have something patches of something looking like orange mould on the inside. I think there was sometimes a damp smell; I wonder if that was why? Does this normally happen or does it show something to look into? Surely the filter would have to be getting wet for mould to grow and it should not be getting damp, should it?

Thanks again, Stephen.

Reply to
Stephen

Thanks. I could have refitted the old plug but I would have had to use mole grips each time I wanted to change the oil, so I thought it would be less hassle to buy a new plug.

I don't have any stilsons. I must admit I've never really known what they are for. They always seem to be sold in the plumbing section of stores, so I thought they were for compression fittings only I learnt from lurking in the diy group that you should use spanners with flat surfaces for these, not the teeth of a stilson. I thought they were for gripping cast iron pipes or something? Are they useful for automotive use? perhaps I should get a cheap set just in case?

Thanks, Stephen.

Reply to
Stephen

Almost correct, stillsons are basically designed for gripping iron or steel pipe, but grey cast iron (like drainpipe) wouldn't normally be a good idea. I havn't needed to use mine for years (I think I bought them when I had to dismantle a gravity hot water system).

You can use them on compression fittings (especially those ones with six ribs rather than a proper hexagon) once they have got rounded off. More for disassembly than assembly!

Reply to
newshound

Stilsons are useful for trying to move anything of any shape whether or not it has flats, so they are a useful thing, but I only very rarely use them on a car.

Haynes are frequently completely and dangerously wrong about things, which is why they are known as the Haynes Book of Lies.

I cannot remember ever seeing mould grow on a pollen filter, they should be changed every other year (as a general guide)

Obviously you should check that you have the exact right Torx bit for the new plug, older vauxhalls generally had a hex head sump plug. Changing the washer is always a good idea, on some cars the plug and washer are one piece and should be changed every time (although rarely are) Torx splines do not tend to strip out, so previous abuse is likely.

Unless you are really interested and have some plans, then buying a welder is unlikely to be very much help to you.

Yearly oil changes are fine for most people unless you do lots of miles. Using the genuine oil and filter is a very good idea.

Reply to
Mrcheerful

Probably not as useful as you might think. You'll need proper instruction and a lot of practice to get competent, and you may only discover bad welds when they fail. Silver soldering is a lot easier.

Reply to
newshound

I've only ever seen copper pipe in domestic situations, so I don't think I would ever need to grip iron pipes.

Is it that these iron pipes had threads cut into them and so there was no separate fitting and so you had to turn the pipe?

Perhaps I should stick with my mole wrenches as it sounds as though they do more or less the same thing?

Reply to
Stephen

I've just replied to newshound that it sounds as if mole grips do the same thing, so perhaps I have no need to buy Stilsons as well?

Perhaps they copied and pasted the text from a book of an earlier model? But of course that is no excuse and it should have been checked before publishing.

I don't know that it was for sure but it was on the "wrong" side of teh filter, i.e. not the side that had collected the dust and dirt and it did look a bit like the mould you get on old bread, although orange rather than green.

The filter did not seem wet to the touch. I've never seen mould on one either but then I've only ever changed one a year on my own car, so I have a lot less experience than you!

It is definitely T40. T45 will not fit and I checked with the dealer too. It has an integral rubber washer, or at least the dealer-sourced one does. Halfords told me they could order a plug and washer but the washer costs £10 more than the plug! The dealer one was only £4.

Yes, I checked the oil spec against the handbook.

Reply to
Stephen

I realise it will take a lot of practice and I don't intend to be doing body repairs nor anything structural. I just thought the "weld something on to a broken bolt" trick might rescue me on other occasions too. Would solder be strong enough for this? I didn't think it would.

That's why I thought a budget model from Aldi, so that I didn't loose much if I was no good. I did look into classes once but they all seemed to be vocational rather than hobby classes, so were very expensive.

Reply to
Stephen

That's the norm for steel water or gas pipes.

Reply to
Duncan Wood

Soft solder wouldn't be strong enough, and you couldn't use silver solder on an in-situ bolt (although you could weld to it, at some risk).

But if you got the plug out, you could (for example) drill out the torx socket to a suitable diameter, get an ordinary bolt and cut off the head leaving a bit of the shank, then silver solder that to the plug, giving you a new and accessible hexagon for a conventional spanner or socket. Silver soldering is often colloquially known as brazing, although strictly speaking that's another process. There's a bit of skill to it, but it's rather like soldering except at bright red heat. Plenty of info and supplies of suitable rod and flux on the net. Flux is absolutely essential. An ordinary plumbers propane torch is plenty hot enough, but you may need to insulate the thing you are trying to heat to get up to the right temperature. You can do this with proper firebrick, with the lightweight vermiculite bricks used to line some types of stove, or at a pinch with ordinary domestic bricks. The secret of a strong joint is to have a relatively small gap between the parts, relying on surface tension to draw the solder into the gap. This is why I was suggesting making a "spigot" arrangement using a bolt. Alternatively you could just file the plug flat, and solder an ordinary hex nut to it, but it would not be as strong.

I know this would all be pointless where you can buy a new plug for a few pounds, but if it were a vintage vehicle with a completely obscure thread, or some more complacted part it might be worth it.

Reply to
newshound

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