Hi All - well I am glad I have not had to post in here for a loooong time, but alas today my little car is having a little issue.
Having passed it’s MOT Saturday, this morning as the sun was out I drive it to work and while in traffic, I noticed steam coming from the front of the car. Not a huge amount, not like plumes, but enough to just catch the eye. I dribbled the last mile to work nice and slow and pulled up to look. The whole of the top of the rad was wet! Do they break at the top or is it more likely a pipe that’s gone that feeds it?
I will have a closer look tonight (assuming I can get it home (only 3 miles) and see what I can see.
The tank is plastic and starts off black, as it degrades and becomes brittle it goes green. If you had not gone far it could be conensation drying, let it tickover until it gets hot and keep an eye on it, It could be a cracked top tank
The radiator top starts black then goes green, then brown. When it gets to an almost tan like appearance, its done. Very often the crack only opens up when the engine is hot. Look for puddles of antifreeze on the radiator support brackets, or the foam strip. Alternatively, check the heater hoses, especially the one that goes behind the engine. On the 1.8, a leaking CAS ring can soften the hose over time, causing it to fail.
It’s definitely not condensation, there was proper water visible so I know for sure there is a leak.
I will check on the colour but it’s not black, I think it’s green or grey but will check and come back. Sounds like a new rad would be a good bet at this point then.
I was going to treat her to something nice as she passed her MOT but looks like that money will be spent on repairs no d’oh!
OK the diagnosis is in: it’s definitely the radiator. I opened the bonnet, and turned the engine on. After about 30 secs it became apparent where the water was coming from. There is a hairline crack that’s developed on the top plastic part, just behind the top up neck. Looks like old age has got the better of it and it’s finally given up. See pic:
So, is this a new rad situation? I presume there is no way to repair that part? Looks like it’s all quite old and tired.
Assuming its a replace, I have a few questions:
What one should I go for?
Will I need any new pipes at the same time (i.e. will I break any getting the old rad out?)
Will I need any new jubilee clips?
Is there anything else that will need, or should be, replaced at the same time?
It’s a fairly simple job. I always use new jubilee clips as a matter of course, and be prepared to need new hoses (do it on a weekday morning so you can get stuff quick) but they should be ok if you’re careful. Also I would flush the system a few times before taking out the old rad / fitting the new, or you’ll just clog your new one with clag.
Did you have cooling problems with the standard rad? If not, I wouldn’t bother ‘upgrading’ - high flow rads are good for track cars and hot countries but not necessary for a road car in the UK.
Nope, never had a problem with cooling at all. Coped OK going round the 'ring last year too, so I guess an upgrade would be pointless. Good advice Sir.
Exactly the same as the crack on my 96. These radiators aren’t unique to MX5s, and others fitted to Toyotas etc, have the same problems. They can be repaired, using various expoxy products, but the longevity is suspect, and wouldn’t the radiator just crack elsewhere. And next time it might be a bit more than a slight puff of steam.
I never had any problems removing the hoses and reusing them and the clips. I fitted a pattern Chinese made radiator from Autolinkuk, and had to transfer over the brackets. The nuts used might be pretty rusted though, so some new M8s or whatever they were, might be handy. If using a pattern radiator (and this might apply to any radiator), give it a good flush through with clean water. Mine was full of aluminium dust.
I would normally say use a new Mazda radiator cap, after having problems with the pattern English made cap supplied by Autolinkuk. But then, I’ve had to recently replace that 2 year old £16 Mazda cap with a £3 effort from Halfords (which is the same as the Autolinkuk item), which seems to be fine.
Surely there are radiator specialists around the country who will rebuild the radiator for much less than a new one. On second thoughts, are they still around?
They are, but the Chinese can make one cheaper than a Brit can fix one. There’s a decent trade in fixing hard to find stuff from classic and vintage vehicles though.
It does seem silly to replace a whole rad for a crack in the top but it’ll go somewhere else soon enough and you don’t want it failing on the outside lane of the motorway.
Ordered a new one from MX5 Parts and it should be arriving today so that’s my plans for Saturday sorted lol
Also ordered some bonnet lifters while I was there. Bit naughty but something possessed my hand and the mouse clicked and added it to the basket. No idea how that happened…at least that’s the official story!
