Coolant leak from engine

[Mx5kieran23]

Hi all,
I went for a drive on Sunday and usually my temp gauge is a smidge below half, and I noticed it started to creep up after driving hard, so I slowed down abit but once I slow right down at a junction or sitting in traffic the temp goes down and will never go higher than 3/4 so I jacked it up and there was a small drip running down the sump and it was defiantly coolant but it only starts leaking when I've been driving for about 15-20mins, also I put some steal seal in the rad on Sunday, could anyone possibly say where the leak is? Or if anyone has had this problem? Thanks Kieran

[getawayturtle]

Which mx5 is it?


If it is a mk1, check the 2 thick heater hoses that go from the back of the engine to the bulkhead. They can perish quite easily. Are there any traces of coolant on the front of the engine? Check around the thermostat (you will need to remove the air intake breather pipe to get a decent look) the 2 hoses around the thermostat housing may be leaking, the thermostat gasket may have perished.

[thecremeegg]

I'd put money on the heater hoses as said above. If the leak is at the back of the engine then this will undoubtably be the cause.
I replaced mine this week with silicone ones and the coolant hasn't dropped since.

[MX-5 Lazza]

First thing to do after fixing the leak properly (my money would be on the hoses too) is to do a coolant flush and change. You want to get rid of that rad seal stuff. The cooling system on MX5s is marginal enough as it is, especially the rads which get blocked very easily. Rad seal will only add to your problems.