Ok so a fairly drastic thing happened when discovering that the Fan Switch was ,…well the Fan switch, and not simply to tell the gauge to operate. After driving for about 20 mins the temperature gauge shot up and well it popped,. Steam ejected from under the hood and I was a little shaken,. Anyway managed to get towed back home and after cooling just to check the engine is ok we ran it for 30 seconds and all sounds fine,. So I’ve purchased a new Rad and the Fan Switch. The Plastic housing on top of the fan completely cracked open and rad cap along with the plastic that surrounds it blew off completely!
My big concern is that this has damaged the head. Are there any ways to tell if this has happened once I have fitted the new radiator,. I’m absolutely gutted as its a low-mileage 56K miles V-Spec Eunos with (apart from that switch) very good engine condition and general up-keep. I fear if the heads gone I might as well forget ownership of the car! PLEASE HELP!!!
M.
Did you say that the plastic tank on top of the rad blew apart?
You might be lucky with the head. Keep an eye out for coolant water loss, water in the oil, oil in the water or white steamy exhaust (water vapour). Warped head will breach the head gasket with one or more of the symptoms above. What has happened is unfortunate but don’t throw in the towel until there is a real problem.
MX5 overheating is all too common but head gasket failure and warped heads are surprisingly rare - you need to buy an early MGF to enjoy this sort of experience:-)
If your head were warped, you would have the symptoms of a blown head gasket as above, you would have a loss of power and rough running, too. Then, when you take the head off and place it against a straight edge, there will be gaps in the middle or at the ends. You use feeler gauges to measure the gap, then shave that much of the head off.
As mentioned, you’re worrying about the very worst possible scenario for overheating. If you don’t have any symptoms, your head is almost certainly fine.