SportKa MOT advisories question - oil leak

AdrianC

Sorry, but...

That is most definitely coming through from the inside, and that is most certainly not just surface grot. That's proper structural rot. A good poke, and that's straight through.

See how the paint is still attached to the crunchiness?
Look at the lower bit, and you'll see that that lot will just pick and flake right off.

Tip of iceberg. Mr MIG welder is going to have to meet your sill soon.

Joe_Horner

Ok, shrunk and copied over for you:




That's fairly nasty for surface rust but, seeing as it passed MOT, not really a problem. Bear in mind that as steel rusts it also expands, so you end up with (visually) more rust than the amount of metal affected

The first thing to do is get rid of the ubbly tuff - thi is one scab that you really do want to pick! Rust is porous and will hold water, which will cause more rust underneath where that water contact good metal.

Don't be shy about getting rid of it. A middle sized flat screwdriver or a paint scraper is probably your best bet initially unless you want to start investing in power tools. Use it to scrape / dig off all the loose flaky stuff. You may well "create" a hole doing this, but don't worry if that happens because the hole was already there under the rust!

Once the obvious flaky stuff's gone it's time to get to work with a wire brush and / or fairly course abrasive paper (about 120 grit wet & dry will do here) until it's all as clean and steel coloured a you can get it. It will be pitted and it [/i]may[/i] be holed by this point. Don't worry.

Next treat it very thoroughly with something like Kurust. You want a fairly warm, dry, day for this so you've probably hit the perfect time of year if you pick your day right. the kurust will chemically convert any rust (iron oxide) that's left into iron phosphate, which is inert. Try not to get any on your clothes - it won't come out - or your skin - it'll turn you purple, but is otherwise pretty harmless. Using it is a simple case of brushing it on so the area is nice and wet with it then letting it work for an hour or so while you have a cuppa, then rinsing off with water and letting it dry well.

Once that's done it'll be much easier to judge what sort of finishing etc might be best depending on how sound the metal underneath is, so another photo around that point would be good

Joe_Horner

AdrianC wrote: »

Sorry, but...

That is most definitely coming through from the inside, and that is most certainly not just surface grot. That's proper structural rot. A good poke, and that's straight through.

See how the paint is still attached to the crunchiness?
Look at the lower bit, and you'll see that that lot will just pick and flake right off.

Tip of iceberg. Mr MIG welder is going to have to meet your sill soon.

Possibly, but could also easily be local stone damage followed by swelling under the paint. Until it's scraped back you can never really tell. It's encouraging that the garage, who've seen it and (presumably) poked it seem to think it's surface.

Whether or not it's "proper structural" also depends entirely on where exactly it is on the sill in relation to prescribed areas and how big the damage is. Perforation outside prescribed areas isn't a problem for MOT or safety, especially if it's localised.

AliceBanned

Thanks for advice. .will respond properly later..it is the only patch as far as I can see. Never spotted it though! Garage said it is not too serious..the only reason noted as advisory was because of seat-belt..but as mentioned it passed MOT at this point.

Joe_Horner

If it's close (within 30cm) of the lower seatbelt mount then they must be happy that it's surface regardless of how it looks because that's in a prescribed area. They will have pushed and prodded it enough to be happy there's sound meta underneath.

Bear in mind that rust takes up about 3 times the volume of the steel it's made from, and that's not including the space taken up by all the cracks and "bubbling" in it - it' the volume you'd get if you crushed it down until there was no air space in it.

So that bubble is probably only a tenth of a mm or so worth in terms of the thickness of the steel. Nothing to worry about at least until it' scraped back to see

colino

Please don't start scraping away at that yourself, get someone to fix it or just slather it in rust inhibitor. That will turn into quite a hole once you dress it back properly.

Joe_Horner

colino wrote: »

Please don't start scraping away at that yourself, get someone to fix it or just slather it in rust inhibitor. That will turn into quite a hole once you dress it back properly.

If it "turns into a hole" then it's already a hole, so will make no difference at all if it does. Better to (a) know what the score is. It could easily be surface only, started from the outside, and an MOT tester who's seen in "in the flesh" obviously thinks it is.

One thing is absolutely certain though. If it is from the outside and it's left like that, with or without rust treatment, it will become a hole soon because it will soak up water and hold it in close contact with the metal underneath.

So, better for the OP to scrape it back and see than not

colino

So your advice to the OP, so clearly not a spanner twirler, is to scrape off that bleb, which will be a hole of at least 100mm and need dressing a long way around that? What will they do with the hole and how will that gaping void be turned into an invisible repair on a metallic blue car?
It most certainly is not just surface rust.

Joe_Horner

colino wrote: »

So your advice to the OP, so clearly not a spanner twirler, is to scrape off that bleb, which will be a hole of at least 100mm and need dressing a long way around that? What will they do with the hole and how will that gaping void be turned into an invisible repair on a metallic blue car?
It most certainly is not just surface rust.

You're basing that on the fact that it "looks crusty" in a photo and ignoring all of the following evidence that suggests it's not as bad as it looks:

(1) It's been advised but not failed on an MOT within the past week because of proximity to a seatbelt mount. If it was likely to be a hole it would have failed because it's a prescribed area..

(2) The OP hadn't noticed it before the MOT, so the paint loss is more than likely the result of the tester having a good prod with the corrosion assessment tool in order to satisfy himself of (1) above.

(3) it apparently wasn't there last year, and it's quite unusual (though certainly not unknown) for even bare metal of typical sill thickness to rust right through in a year from sound metal

(4) Having given the advisory, the garage has suggested that she doesn't worry about getting it done - unusual for a garage to voluntarily advise against having profitable work done. Again, that strongly suggests that it's not a hole under there.

(5) even ignoring all that, seeing as the paint loss is "2 inches in diameter" (by which I assume the OP means the longest direction), that 50mm bubble is not going to turn into a 100mm hole. So stop scaremongering.

(6) even ignoring all that, you're adamant that it's effectively already a large hole (a hole filled with rust has ZERO strength) yet you're suggesting that the OP "slathers it in rust converter" and drives around with her lower seat belt mount ready to rip out of the car in an accident.
Personally, I'd much rather know the true extent of the damage before advising someone to do that.

(7) If you've never seen surface rust that looks that bad (or even worse) before it's cleaned up then I'm afraid you don't have as much experience as you seem to think.

Given the 7 points above (especially 1, 2, 4 and 6), yes, I'd advise the OP to scrape it back and see what's underneath.

colino

OK, I will guarantee that the picture indicates both an area of rust from within and one accelerated either by a kerb or jack knock to the exterior sill. It will, I guarantee, turn into a hole when scraped.
Please keep on making ill informed comments, I'm sure it entertains some, especially that the NT caused the damage in the picture using a PAT. He would have been sacked by now, even if he had the miracle skill to make his recent, "prod" just as rusty as the already, badly, deteriorated sill.
You really don't understand the 30mm sphere the NT has to visualise when assessing a car for rust, the car passed, but that rust isn't going away and it will be a mess in 3 months time, never mind next MOT.
7 numbered points to say nothing and still no advice to the OP what to do with the damage you have suggested creating. Well done, keep on gathering your, "evidence".