Is rust a problem on early MG5s?

[Alb]

Mine's just over 4 years old and no rust.

 

[Paulie68]

Mine's just over 4 years old and no rust.

Really?, not even under the bonnet around the pressed holes? They all go rusty there!

 

[Alb]

My reply was given in the context of this specific thread.
The corrosion in those photographs is unusual in the extreme.

 

[Paulie68]

My reply was given in the context of this specific thread.
The corrosion in those photographs is unusual in the extreme.

I agree, It really is terrible!

 

[Robbob]

I live by sea 64000, bought during covid. No rust whatsoever, even where I have two stone chips. I live in a seafront area, so it's always coated in sand and salt. Red at MG5.

 

[5teep]

It looks like some cars were built with sub standard steel (

 

[Alibro]

I have a white 2021 MG5 and have painted rust spots around the holes under the bonnet a couple of times. The car has less than 20k miles.

 

[Data]

It's been known for some manufacturers to use steel that has not been 'weathered'. As some will know this process involves stacking sheets of steel used in the production of cars out in the weather, unprotected from rain etc. Some manufacturers even spray the new steel with salt water to speed up the corrosion of the steel. This is carried out to allow natural processes of oxidisation to 'corrode out' the imperfections in the surface of the steel sheets. Without this being done the imperfections can start the oxidisation process under the surface of the painted metal. Car makers are sometimes tempted to do this when weathered steel become in short supply & to save closing down a production line they grab some unweathered steel to use instead.

My car is a new ZS EV & I've just coated it underneath with Waxoyl & Bilt Hamber box section wax. Hoping it won't rust. I haven't seen any rusty ZS's so far underneath & I've seen a few up to 5 yes old. No rust. Not seen any MG5's either.

 

[Paulie68]

It's been known for some manufacturers to use steel that has not been 'weathered'. As some will know this process involves stacking sheets of steel used in the production of cars out in the weather, unprotected from rain etc. Some manufacturers even spray the new steel with salt water to speed up the corrosion of the steel. This is carried out to allow natural processes of oxidisation to 'corrode out' the imperfections in the surface of the steel sheets. Without this being done the imperfections can start the oxidisation process under the surface of the painted metal. Car makers are sometimes tempted to do this when weathered steel become in short supply & to save closing down a production line they grab some unweathered steel to use instead.

My car is a new ZS EV & I've just coated it underneath with Waxoyl & Bilt Hamber box section wax. Hoping it won't rust. I haven't seen any rusty ZS's so far underneath & I've seen a few up to 5 yes old. No rust. Not seen any MG5's either.

I'm sorry, but what you just posted is total and utter nonsense. Sounds like an April 1st joke!

Sheet steel for car production is kept dry and clean, there is no such thing as "weathered" sheet steel, if you knew anything about metallurgy you'd understand why what you posted is utter rubbish. If sheet steel is ever allowed to start rusting prior to painting, it will never stop, and the paint will fail.

In any case, most sheet steel is now zinc galvanised when used in car production, for longevity and this process only works on perfectly clean steel.

 

[5teep]

I'm sorry, but what you just posted is total and utter nonsense. Sounds like an April 1st joke!

Sheet steel for car production is kept dry and clean, there is no such thing as "weathered" sheet steel, if you knew anything about metallurgy you'd understand why what you posted is utter rubbish. If sheet steel is ever allowed to start rusting prior to painting, it will never stop, and the paint will fail.

In any case, most sheet steel is now zinc galvanised when used in car production, for longevity and this process only works on perfectly clean steel.

I had one of the first Dacia Dusters that were made in India, they supposedly stored some of the steel outside and it lead to huge issues with rust a few months down the line for some cars.

 

[crispyjay]

I'm sorry, but what you just posted is total and utter nonsense. Sounds like an April 1st joke!

Sheet steel for car production is kept dry and clean, there is no such thing as "weathered" sheet steel, if you knew anything about metallurgy you'd understand why what you posted is utter rubbish. If sheet steel is ever allowed to start rusting prior to painting, it will never stop, and the paint will fail.

In any case, most sheet steel is now zinc galvanised when used in car production, for longevity and this process only works on perfectly clean steel.

From my body in white automotive adhesive bonding days I can confirm everything is galvanised but also covered in oil not dry.

My adhesives had to bond to oily steel and not get washed off through degreasing baths!

 

[Data]

I'm sorry, but what you just posted is total and utter nonsense. Sounds like an April 1st joke!

Sheet steel for car production is kept dry and clean, there is no such thing as "weathered" sheet steel, if you knew anything about metallurgy you'd understand why what you posted is utter rubbish. If sheet steel is ever allowed to start rusting prior to painting, it will never stop, and the paint will fail.

In any case, most sheet steel is now zinc galvanised when used in car production, for longevity and this process only works on perfectly clean steel.

Thanks Paulie for pointing that out but you clearly haven't been present at a car factory when sheet steel is being delivered. And it certainly isn't an April fools type joke. When I've seen this the steel was already quite rusty. Albeit this was a few years ago & sure processes may have changed I fully accept that. I'm now retired. It may be the process isn't popular at the factories now, it's been a while since I was involved at that end of the business, but generally the steel is still weathered if needed before galvanisation as it will still contain impurities. It may be artificially weathered more quickly these days but it's still weathered. We are NOT talking about CORTEN STEEL type weathering. That's not required. We only wanted the early corrosion that takes place. Yes I know you can get differing grades of steel with differing levels of impurities or purity. But some of those can be very expensive. I've seen our sheet steel covered in rust after initial weathering then dipped in an acid bath & coming out completely clean & shiny without those surface imperfection at the other end. Under the microscope there is no trace of oxidisation. Trust me, I've seen it, It's then galvanised or processed in whatever manner is required. I suspect some of this is carried out at the steel factories now but car bodies once built still undergo various electrostatic & electrophoretic treatments after acid baths. I'm sure these processes have been refined also over the years.

I do still see new cars rusting underneath along seams that have no sealant or other protection over them. Not so much MG's yet but I've seen many other makes rusting after just 2 or 3 years. Even Honda's & those used to be pretty good. My Citroen was 7 years old with no rust whatsoever because I gave the car a good soaking in Waxoyl & Bilt Hamber when it was new. I think this is a good idea when you get your new car or if it's two or three years old. It should considerable lengthen the cars life.

I came into the motor industry when there was no galvanised metals or any other fancy processes to prevent rust. Weathering of the type above was widely used for SOME parts of the car at the factories. I'm pretty sure there was a video showing this short term weathering as they called it, by VW. This was some years ago on some tv documentary. I do wonder if it's still used in the far eastern factories!

 

[Paulie68]

Thanks Paulie for pointing that out but you clearly haven't been present at a car factory when sheet steel is being delivered. And it certainly isn't an April fools type joke. When I've seen this the steel was already quite rusty. Albeit this was a few years ago & sure processes may have changed I fully accept that. I'm now retired. It may be the process isn't popular at the factories now, it's been a while since I was involved at that end of the business, but generally the steel is still weathered if needed before galvanisation as it will still contain impurities. It may be artificially weathered more quickly these days but it's still weathered. We are NOT talking about CORTEN STEEL type weathering. That's not required. We only wanted the early corrosion that takes place. Yes I know you can get differing grades of steel with differing levels of impurities or purity. But some of those can be very expensive. I've seen our sheet steel covered in rust after initial weathering then dipped in an acid bath & coming out completely clean & shiny without those surface imperfection at the other end. Under the microscope there is no trace of oxidisation. Trust me, I've seen it, It's then galvanised or processed in whatever manner is required. I suspect some of this is carried out at the steel factories now but car bodies once built still undergo various electrostatic & electrophoretic treatments after acid baths. I'm sure these processes have been refined also over the years.

I do still see new cars rusting underneath along seams that have no sealant or other protection over them. Not so much MG's yet but I've seen many other makes rusting after just 2 or 3 years. Even Honda's & those used to be pretty good. My Citroen was 7 years old with no rust whatsoever because I gave the car a good soaking in Waxoyl & Bilt Hamber when it was new. I think this is a good idea when you get your new car or if it's two or three years old. It should considerable lengthen the cars life.

I came into the motor industry when there was no galvanised metals or any other fancy processes to prevent rust. Weathering of the type above was widely used for SOME parts of the car at the factories. I'm pretty sure there was a video showing this short term weathering as they called it, by VW. This was some years ago on some tv documentary. I do wonder if it's still used in the far eastern factories!

Back in the 70's British Leyland, due to their stupidity, let steel sheet get wet, whilst waiting for it to be processed in the pressing shops, leading to rusting. Some bodies in white were also transported in the rain between factory buildings. This was not part of the planned process, but incompetence and as a result some of their cars suffered from appalling premature corrosion.

No one has ever "weathered" sheet steel, or allowed it to rust on purpose prior to processing it into car bodies, certainly not VW!

VW process, back in the day would use new unprotected sheet steel coils. These were covered in a film of oil to ensure there was no rusting whilst in transit and until they were in the dry indoor factory environment for final processing. they were then cut and pressed into panels and welded into a complete body. The body was then washed clean in a detergent bath to remove oil residue, followed by a rinsing bath, then a zinc phosphate primer bath. From there they went into the paint shop.

There was most certainly never any purposeful weathering or rusting of the steel at any point!

 

[Data]

Yes, BL cars suffered terribly from the dreaded rust. Ford had similar issues too. Look how quickly some of the BL models disappeared from the roads. I was there looking at their processes amongst other things. They had no money...that was the basic issue mostly caused by bad management & unions who ruined the company & prevented any proper modernisation. Successive governments didn't help much either. Everyone was clueless.

Just to add, there were not many UK factories I didn't visit as part of my work, & some european. I knew all of the car production processes. Of course over the last few decades things have advanced but in the era I am talking about the processes I have described were quite common. To be clear not all steel for the whole car was treated in this way. I understand you don't know this. But that's ok, why would you. I'd point out that VW also had a considerable corrosion issue at various times in the 70's & 80's & to some extent in the 90's as did others.

 

[Herandnu]

Very rare to see cars rust like that these days. I thought we'd gone back to the 80s for a moment looking at some of those pictures!.

 

[MGEV5]

Just to give an update on the attached corrosion issue
MG said they were not accepting responsibility for the rust issue but were offering £800 towards repair costs. Work that one out !!
Lex sent the car for inspection to one of there repair shops

They advised that the car needed approximately £6500 of repairs to replace and repair the effected panels

Unbelievably the car has now been WRITTEN OFF by the company insurance

So for context a 4 year old car with no problems mechanically and has never been in an accident is declared a total loss due to rust

 

[5teep]

Just to give an update on the attached corrosion issue
MG said they were not accepting responsibility for the rust issue but were offering £800 towards repair costs. Work that one out !!

That's standard, if they accept responsibility for yours they accept it for everyone's.

 

[PeterHR2]

The last thing any press shop producing body panels would want is a pre-press rusty sheet of steel going through the press. Transfer of rust to the tool faces would accumulate and lead to scoring of subsequent panels and even the tool itself, resulting in even more scored panels and significant tool downtime for repair and panel rectification costs.

Annealed, cold rolled sheet steel had/has a mineral oil coating when leaving the steel plant, even in the 1970s. My experience in both British Steel and at PSF was that rusty top sheets from a pile of blanks were always discarded to join the scrap pile for recycling or repurposed, maybe in smaller parts, if the grade was 'right' or if some in-house fabrication was needed.

Rust in cars nowadays is more likely a fault in manufacturing as a result of incomplete cleaning/protection/paint shop issues (possibly because of design features like awkward re-entrant angles and drainage issues) or subsequent damage.

Use of 'weathered' steel would always have been bad practice.

That said, CorTen is a 'weathering' steel (though never used in mass-produced cars to my knowledge) used for stuff that wasn't/isn't ever going to be painted.

 

[Black estate]

That said, CorTen is a 'weathering' steel (though never used in mass-produced cars to my knowledge) used for stuff that wasn't/isn't ever going to be painted.

This steel is used In shipping containers and they have a label on them saying only use Cor Ten steel for repairs

 

[OriginalBigAl]

From my metallurgy classes back in the 70s a lecturer informed us that BL cars rusted quickly because they wanted steel with a 4% addition of aluminium. This was more ductile and easier to form and so the pressing moulds lasted longer . This aluminium lay at the grain boundaries of the steel and caused electrolytic corrosion from within .
When my MG4 was brand new I lifted it up on blocks and removed the rubber grommets in the cills.
Peering up with a torch into the interiors it could be seen that were coated in a thin oily type substance .
The trouble with zinc coated ( zintec ) steel is that the zinc burns off at every spot weld so surrounding every weld is an unprotected area which if not properly re- protected could be a start point for future corrosion.