Rust but not rust as I know it.

[warrenpfo]

I wiped the front bumper and grill off this weekend to have a look at what is going to be required when it comes to mounting the ARB as well as to see if I could get at the 2 bolts with snapped heads (I cant but did manage to drill one out with a masonry bit so only one more to go, yay).

On closer inspection of my radiator it would seem that where it mounts to the body and chassis there seems to be some “rust” developing. The problem is that its not rust as I know it all brown and flakey but rather white and powdery and am not if it is rust.

I seem to remember being told that certain metals don’t like each other and that there can be a chemical reaction between them but am not sure if this is what I am experiencing and if to how best to tackle it before it gets to bad and the radiator mounts disintegrate.

Has anyone experienced this and could they advise on what I should do. My thinking was to undo the bolts and place a small/thin piece of something between the two metals to create a barrier of some form but not sure if this will work.

 

[Euan McGilp]

Sounds like an electrolytic reaction between 2 metals as you suggest. Clearly, the 2 surfaces should not be touching in the first place.

Ideally you need to stop them touching - usually paint would have been the answer, but if the rad & panel are touching, then you need to separate them first. This could be achieved by fitting some kind of thin plastic spacer between the two materials - but what has caused them to touch in the first place? (this needs to be sorted 1st)

Is the contact & subsequent reaction caused by slack mountings / previous impact damage resulting in something misaligned / someone leaning on top of rad & bending mounts? Solution could be to sort/level brackets & repaint rad bottom tank / chassis & maybe then slip in a rubber or plastic (as simple as ice cream tub plastic) packer. Your plan is absolutely right - BUT remember, if you put in a physical barrier without making more space for it to fit, you risk increasing the speed at which the rad could fail because it is now 'pushing' harder on another surface.

 

[frank rabbets]

I assume it is the aluminium radiator ? When combined with steel/iron and water bimetallic action occurs forming aluminium oxide which is the white powder. If salt is added to the water the reaction is much quicker. If your car has lived by the coast the salt in the air will make things worse. Salt is hygroscopic and it takes a lot of heat/dryness to dry it out. I have found the best way is to seperate the joint and pour plenty of boiling water over the areas to wash of the corrosion and salt. Then blow dry with an air gun. A barrier helps but does not cure. Then pour plenty of waxoil to the area and bolt up together. There is no cure for the long term. Even damp air seems to keep the reaction going. Any pics yet.

Frank

 

[OG.]

You could try fitting a rubber grommet or pair of rubber washers to prevent metal to metal contact.