MX5Ireland

Lads & lassies,

Recently I flushed the cooling system and replaced the thermostat as I thought
it was slow to warm up. Ever since I am losing coolant through the overflow
pipe on the header tank. Any ideas ?
I bled the system as best I could and even put back in the original thermostat
in case the new one was a dud but it still seems to be pushing water out
through the overflow when warm.
All suggestions welcome.......

id bet a shiney 50p that its your rad cap

does the car gurgle after you have driven it then park up and switch off ?

that will be the cap

get the cap checked . Any good local garage will have a pressure testing kit. Cap opening pressure should be between 11-15 psi (74-103kPa).

I haven't noticed any gurgling from the rad cap. In fact all looks okay until
you look down by the front wheel to see water dripping off the bumper !
(Coming from the tank).
However, I have a recent newish rad cap in the garage so I'll try this tomorrow.

Oh well, looks like I'll be using the new torque wrench that I bought today
really soon.......to lift off the head ! Top end rebuild imminent.

For real ? wow

If it isn't rad-cap, coolant overflow cap and thermostat it could be that the water pump has broken up and isn't churning the water.

Did you get a sniff test done on the coolant, to see if there's any evidence of oil/exhaust-gas mix ?

Sniff tester http://www.sealeyonline.co.uk/vs0061-combustion-leak-detector.html

Ouch, I thought they were cheap but they are > STG90. Any mechanic/garage should have one though.

def not the cap? Maybe borrow a known good rad cap before pulling the head?

When I first bought the car I had a hunch that it would need top end work as it
was running a little lumpy on initial start up and also traces of slight blue smoke.
The previous owner also suspected that it was a worn valve. My suspicions were
growing when I felt the manifold on No.2 cylinder. It was slight colder than the
others. I ruled out the plug wires, spark plugs etc.
I spoke to a mechanic yesterday that reckons a part of the head gasket is
probably also damaged thus causing the coolant scenario.
I did actually replace the rad cap with one from my 1.6 but to no avail.
The question is now, do I do it myself or pay someone to do it ? I have a house
renovation happening soon and also I need to fettle one of my motorbikes for
a European trip in May.........is it possible to buy units of spare time ?!?!?
Although there's a fair saving to be made going the DIY route.