Radiator sizes and qualities?

[Ian Hulley]

Sounds like it may not have been 'perfectly good' after all. Maybe it was gradually clogging up.

Exactly my point ... nothing outwardly to indicate any problem but on the same run each year it was getting progressively hotter.

[colinthefox]

Another thing that gradually deteriorates on old rads is the fins. They corrode and crumble at the point of contact with the tubes (even if they look OK), especially low down on the rad. This can reduce the cooling efficiency considerably, even if the water side is perfectly clean.

[boatbuilder]

Well I'm saving up for a proper decent Hella unless there are any alternatives

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[malcolmtrot]

I'm a bit of a novice at all this but had a similar issue after swapping a heavily corroded copper radiator for smaller aluminium (nobody had stock of thicker one). The temp was consistently higher and went up past 3/4 on a very steep, slow hill. Have now swapped to the 44mm BW Hella Behr one and the gauge hardly moves from middle. Seems to be so much more efficient and well worth that extra money.

[CJH]

I got my radiator back from being tested today - it passed all its test perfectly fine. It was pressure tested up to 20psi, flow tested, and also had hot water pumped through it to make sure all parts got hot. And it's fine. The only slight concern was that some of the fins looked as though they've gone brittle. But I'm none the wiser as to how it actually performs in comparison to my new 44mm radiator. I think I'm going to fit the new one after all, since I know for sure that it's perfectly ok for a 2.1. I'll keep the old one as a known good spare.

So what's the collective wisdom over giving the new one a light coat of black paint? We all remember from school physics that black objects radiate heat better than lighter colours, and that would seem like a good property for a radiator. And a bit of paint ought to help against corrosion. But if it's beneficial then why don't the manufacturers do it? Is it that the small amount of extra radiation efficiency is outweighed by a small thermal insulation effect from an extra layer of paint?

[Jawin89]

Eurocar parts have the Hella radiators back in stock again. The code weekendsale gets you extra discount and they come out at £48!!!! Bit of a bargain really

[marlinowner]

Virtually all the heat loss from the radiator is by convection, the colour doesn't really matter. Matt black rather than gloss white might be worth about 1% extra cooling through radiation, but an extra coat of paint would negate that.