Radiator colour: brown = bad plastic right?

[gslender]

Hi,

When inspecting a NA8 or NB8A model MX5, is it correct that the radiators that are brown in colour may be an indicator of the plastic on the way to failure? I've seen a few comments to suggest that, but I'm now seeing a fair few of the later models with brown radiators, whereas the earlier NA6 models seem mostly a healthy black colour.

So, can anyone confirm or report that either a) the stock OEM radiator for a NB8A is indeed brown, or b) nope, if it is brown it is likely to be ready to fail in the future.

G

[JBT]

It could be that the older cars with black top tanks have either had new tanks fitted or are painted. They were always black when new and the brown change is generally an indicator that it won't be long before it lets go or cracks. Top tank replacement is relatively cheap and works well if the cooling system has been looked after.

My 1995 NA8 top tank went brown in 2002 and was replaced with a nice new black one in 2004 when it started to crack. I wonder what colour it is now?

[sailaholic]

Seen 3 Cadbury coloured na units, only 1 still exists, the others failed.

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[manga_blue]

I replaced my 12 year old one when it was a greenish milk chocolate brown with a hairline crack along the top. Cost was $80 including pressure test and clean. Six years on and it's still black.

[NMX516]

The tanks on my standard NB8A radiator were a healthy black colour.

[gslender]

Thanks guys - I guess the few NA6 models I own and have seen have probably been replaced in their lifetime, whereas the newer NB models probably might still be running on the original (though brown) radiator... good to know that brown = bad (as in life).