Very tight sump plug (Sigma)

[FramerateUK]

I intended to do an oil change on Sunday (car last had a chance in January while it was have a once over at QMech), however I hit a huge stumbling block when trying to get the sump plug out. It simply would not budge! I tried everything to get it loose, but eventually, after getting a piece of pipe over my socket wrench to give me some additional leverage, the wrench itself buckled with the sump plug itself still in place!

 

So, I gave up for the time being and did my oil chance with my vacuum pump (gets the oil out of the dipstick) which will be fine for now, but I really would rather get that sump plug open! Any suggestions of how to get it to move? I tried some WD40, but I'm afraid to put too much force in case I just end up taking the head off.

 

I'm thinking I might just leave it until it goes back it's yearly checkup with Andy at QMech in January unless anyone else has some suggestions?

[Birkin S3 ZA.]

If your sump is strong enough and its got a copper washer under the plug, give it some good sharp blows with a hammer to squash the copper washer then it will come undone.

Or you could try and rotate it a bit with a hammer and chisel, or try some heat from a gas welding torch.

One of these methods always works for me.

Chris.

 

[FramerateUK]

That's the problem really, I don't know what's under there as I've not removed it myself before (only acquired the car shortly before it was serviced).

 

How tight should the plug be? I mean, I assume it has to be tight enough so that it doesn't come loose and cause an oil slick, but should it be as tight as this?

[Crudders]

I've never had this problem on a sump plug but a very tight oil filler plug on an Imp transaxle a few years ago succumbed to the torque of a jack placed under the wrench, using the weight of the car where muscle power had failed. I did calculate the torque at the time - I can't recall the figure but it was quite considerable!

 

I'm not familiar with the Sigma but I presume it has a smallish steel plug in a cast ali pan? You may cause damage removing the plug but then it can't stay there forever. A little localised heat from a mini gas torch might help, and there are always Helicoil inserts and the like if the need arises.

 

HTH,

 

Cruds

 

 

 

 

 

 

 

[Birkin S3 ZA.]

If it has a aluminium sump drain plugs always seem to lockup in these for some reason, many times I have take care not to over tighten a drain plug only to find it very tight at the next oil change.

Chris.

[CharlesElliott]

25Nm, at least on a wet sump K-series.

 

They do tend to 'stick' in as the deformable washer/bolt head mould to each other.

[SKC]

Hi Frameateuk,

 

Whatever you do just make sure you use a single hex socket, this will put the maximum amount of loading on the hex of the plug without rounding of the corners. Once you've rounded the corners off the plug then your into mole grips and drilling the plug out....let's try and keep it simple for now. I'd recommend a bit of heat from a blow torch and a long bar with a socket on the end. You could try giving the socket a bit of a tap with a hammer first to ensure it has a good purchase on the plug.

 

Good luck!!

 

Regards

 

SKC

[charlie_pank]

All solutions have got to be easier if you just remove the sump from the engine?

[SKC]

Hi Charlie Pank,

 

This isn't a big issue. At least with the sump rigidly bolted to the engine in the car, your not trying to chase the sump round on a bench top, garage floor or the kitchen worktop (when the wife's out)!!.

 

Best regards

 

SKC

[7 wonders of the world]

Excessive torque with long bars can causes breakage, use a single hex long spanner and give it a good swift crack with a copper mallet - the shock will free it.

 

If your worried under tightening (to prevent reoccurrence) and the risk of the sump plug coming out then you could drill the plug and a suitable cooling fin on the sump and lock wire it in place.

[Born2Run]

Visit your local garage and ask them to use the wheel nut air gun with appropriate sized socket. For a beer most will give it a go and the shock action usually loosens most stuck bolts. I have seen so neat battery powered versions recently. Think I might invest in one myself - handy.

[Stationary M25 Traveller]

I would try heat on the aluminium around the bolt .... and maybe some PlusGas trickled behind the bolt head a day or two beforehand so it can creep into the thread

[elie boone]

Just run the engine up to temp, give your key a good wack and lightly reseal, let the engine cool for some time and then change the oil.

[FramerateUK]

Thanks for the help guys.

 

The only difficult with getting under the car when it's still hot is that on the Sigma the exhaust is the same side as the sump plug so it's hard to get under without 3rd degree burns!

 

How do people feel about the oil extractor tools? I've been using them on my normal car for years for interim oil changes. On the Caterham thanks to the design of the sump, the dipstick shoot and the sump are on opposite sides of the sump and it doesn't appear there's much advantage to using the drain as opposed to the pump?

[charlie_pank]

Quoting SKC: 

Hi Charlie Pank,

 

This isn't a big issue. At least with the sump rigidly bolted to the engine in the car, your not trying to chase the sump round on a bench top, garage floor or the kitchen worktop (when the wife's out)!!.

 

Best regards

 

SKC

 

use a vice

[Stationary M25 Traveller]

Quoting FramerateUK: 

Thanks for the help guys.

 

The only difficult with getting under the car when it's still hot is that on the Sigma the exhaust is the same side as the sump plug so it's hard to get under without 3rd degree burns!

 

How do people feel about the oil extractor tools? I've been using them on my normal car for years for interim oil changes. On the Caterham thanks to the design of the sump, the dipstick shoot and the sump are on opposite sides of the sump and it doesn't appear there's much advantage to using the drain as opposed to the pump?

same on the K-series. I raise the front of the car, support it on axle stands then get underneath from the front.

 

Edit ... I am very anti the extractor tube method. Can't beat gravity and the flow rate from a sump plug drain when oil hot.

 

Edited by - SM25T on 3 Sep 2013 15:45:37

[Jonathan Kay]

Good advice above.

 

NB WD40 has no or very little releasing effect. Use PlusGas or, apparently, Coke.

 

If the old oil is coming out looking nice and clean, and IMHO for most 7s with typical changing intervals it does, then sucking the old oil out won't be very different from draining it. Perhaps in theory sucking would be less effective at removing metal particles.

 

Jonathan

 

[Jonathan Kay]

Duplicate post deleted

 

Jonathan

 

 

Edited by - Jonathan Kay on 3 Sep 2013 15:51:11

[Martin J]

Not a copper washer used on the sigma but a rubber o ring set into a recess on the sump bung.

Sounds like some gorilla has over torqued it last time it was done up.

[FramerateUK]

Just spoke to Andy at QMech and he said they're usually removed when the engine is hot and are torqued to 25nm. He was a bit surprised it was stuck in there but offered to have a look at it. It's not a huge problem at the moment since so he can have a look when it's back with him in January. I can't see us doing a huge amount of mileage between now and then anyway.

[elie boone]

Extracting the oil from above is common practice on modern cars, it just takes to long to undo the underbody and you have no problem with the drain plug.

[Martin J]

Assuming you are heaving on it anti clockwise (sorry 😳) I would fit a good quality ring spanner & give it a sharp whack with a hammer. I think you just need to shock it.