Hi all,
I was looking around a mk3 yesterday and spotted this bubble under the bonnet next to the catch. Is this a common feature, or a sign of abuse in the past? The colour match is near-perfect so it could have been there from new.
Looks like a wee bit of subcutaneous corrosion to me. I’d have it wet n dried down to bare metal & repainted sometime soon. then inject POR15 or similar rust fighter through these holes. Doubt it’s been there from Hiroshima.
If its a Mk3 then the bonnet is Aluminium. So it wont Rust.
I would rub it back and Prime / Paint.
The bonnet and boot skins on the soft top Mk3 are aluminium welded on to a steel frame, the coupe has a steel boot skin.
Aluminium will corrode but it does not keep going like steel as the oxide creates a barrier, the big problem for us is Galvonic corrosion where another metal joins the aluminium and there is the chance of electrolytic corrosion.
Not sure about this bubble though, would have thought that part of the frame would be steel.
Get it off and protect it would probably be the best advice.
I am not certain but seem to remember hearing that all Mk’s bonnets are aluminium, part of the 50/50 weight saving.
I hadn’t realised it was aluminium, so the magnet came out again. Not attracted to the bonnet. Although the bonnet is almost certainly metal judging by the way it sounds(rings) when closing or rapped by my Knuckles. I think you are right, it probably is aluminium.
Gales
The Bonnet is definitely ALL aluminium as is the boot (On the Soft Top - Steel on the RC). At least it is on my MK3.
I have some corrosion around the number plate lights - which seem s pretty normal on a Mk3! I will get around to it in the summer.
Hmm, on my Niseko (Mk3 PRHT) the magnet test reveals that the bonnet is all Ali - both skin and frame, but the boot is all steel - both skin and frame.
And yes, the retractable hard top is definitely some kind of white/cream plastic - according to some tiny scratches on two edges where it might have rubbed in the past.
Yup. Alloy skin but on steel frame. Funnily enough, I recall a UK ltd edition with an all steel bonnet that was some sort of pattern replacement.
Did not know they were even made. It felt a ton weight in comparison!
Likewise I have some corrosion around the number plate lights. Being aluminium has anyone got some suggestions as to what sought of primer to use i.e. Red oxide etc or is there a ‘special’ primer for ally?
The PRHT roof is made of sheet moulding compound (outside) and GFPP (inside). It is “composite” but not in a carbon fibre sense as some have previously claimed.
“They all do that Sir”
As above
common on bonnet and boot lid