Would you replace this radiator?

Currently in the middle of a Cambelt service and Seal change. Pulled out the radiator and found it’s flaking like crazy and is quite green. I suspect it’s probably the original from factory. It doesn’t appear to be cracked or leaking, but the drain plug is rounded off and it’s got 150k miles on it.

Would you replace it, or does it look worse than it is? I’m leaning towards replacing it.

Was just going to get a cheap aftermarket one to replace it if so. Is Mx5Parts the best place to get them, or is there another better place?

Google a local radiator recore specialist and compare price.

A recore wont last as long as a new one though, but is cheaper.

Seen a lot worse.
It’s not leaking so still strong and cooling efficiently.
Some of the cooling vanes are squashed but should be fine.
Reverse flushing could bung it up (as you say flaking).
As it’s out make a wooden/plastic tool to fit between them (time and patience permitting of course) and straighten them out.
Or get a new one.
Quite difficult to assess properly by just photos.
Perhaps best to go with your gut feeling and budget. :slightly_smiling_face::+1::man_shrugging:

I purchased a Nipparts radiator from Autolinkuk years ago. Its basically identical in appearance from the factory radiator. The radiators tend to fail in the top plastic part. It was about £70, so not a lot, and currently they seem to be the same sort of price.

When fitting this rad, I took the precaution of giving it a good flush. The innards included lots of aluminium dust. The plastic drain plug is completely different from the Mazda one, and I suspect replacements would be hard to find.

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Well, if you can get a new one for around £70 (as Saz9961) then a bargain and decision made in my opinion. :slightly_smiling_face::+1:

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I was referring to a Mk1 radiator, but from the OP’s posting history, I’d assume he is replacing a Mk2 radiator, which are a bit cheaper than the Mk1.

Autodoc are listing lots of different brands, but I’m not sure why anyone would go for the mega expensive Valeo radiators.

Yeah it’s a Mk2. Can get a new one for £70ish so it’s a tempting prospect. I’ve gotta refill the car with £20 worth of coolant anyway, so might as well put it in a new rad than in one that might leak or crack soon.

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I replaced the rad on my Mk2 when I changed the cam belt. I’ve had old cars with troublesome rad issues before and the one on my car looked marginal so I had my doubts about how reliable it would be. I fitted a new bottom hose at the same time because it’s trickier to get at than the top hose. The old hose looked to be in reasonable condition so I decided to keep it as a spare.

That reminds me, one day I must repaint the tatty looking top brackets holding the radiator in. I keep intending to do that….


Good point, the top brackets on mine don’t look great. A bit of a sand down/wire brush and a respray would be really make them look nicer. I’ve even got a can of 18J colour matched spray, so can colour match it to the paintwork.

Hi Graham123,

Not sure what you mean by flaking i.e. inside or out?

My gut feeling says carefully straighten the fins using a small pair of long nosed fliers. Then get it pressure tested or test it yourself using a tyre inflator or pump.

If a few fins break when straightening, ignor it, they are only fins to aid air cooling and I have seen way worse than your rad used by others for many a year.

If it tests ok maybe a quick spray with an appropriate primer and a spray with say a black spray can.

Having it recored or buying a new one is a consideration but working is working and if it ain’t broke don’t fix it.


If you gently running your finger down the fins and they literally flake off in clumps as they are so brittle. It doesn’t appear to be leaking, but it’s certainly the original one and heading towards the later part of its usable life. Doesn’t help that the drain plug is completed rounded off.

If the fins are that bad, recore it or get a new one then I recon. Salty roads and aluminium is a pain.


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New ones are not that expensive anyway. I got one on next day delivery for around £65 from trade vehicle parts. Mx5 parts had no stock.


Hi graham

zero thanks given and good advice given, what do you expect?

Apologies if I came off a bit rude or ungrateful. I am thankful for the useful advice I’ve had from everyone here. I ended up ordering an after market one for £65ish which seemed like a the best option. Planning on holding onto the car for a while so worth it for the peace of mind!

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Well done!

I would have recommended, but at the end of the day, if you cannot be bothered to show any gratitude, what is the point?
My apologies, I see you have thanked previous posters :blush:
My advice is that the top tank looks green which generally means it is old and tired. Do a flow test, simply a hose in the top port and see how flow is at the bottom.
I’d say that it needs replacing, coolpartsUK would have been my goto supplier for easy supply online but they seem to have lost the plot with pricing.

I’d replace it - it’s out now so easier to do, not that it’s a difficult job.

I put an IL Sports radiator in my NB, cost £110 to buy, gives bigger capacity so increased cooling and not something I need to worry about now. I also fitted a grill cost about £10 to the scoop mouth to stop anything getting in and damaging it - took 10mins to fit and not much more for the radiator.

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