Hi, I’ve got a 2001 1.6 NB MX-5 and I’m having some overheating issues. I bought the car to learn to do some more complex mechanics as I enjoy working on cars. I’m regretting it already! I’ve got an overheating issue which I’m struggling with, it comes in two parts. The car has an aftermarket digi…

Have you checked radiator ? Mine was partially blocked. Easy to check, make sure it’s evenly hot all over once water flowing hot by feeling with hand. Obviously turn it off before putting hand near pulleys or fan.

I haven’t checked that, no. All I checked on the radiator was that the top hose got hot, the cap held pressure, and that it didn’t leak. I’ve run two lots of radiator flush through the system and it’s an upgraded japspeed radiator so I just assumed it would be fine!

Mine had good flow but was large section that wasn’t heating up so obviously had some blocked channels. Tried various methods to flush out but wouldn’t clear. Bought a new rad in the end . Wasn’t too expensive, about £100 I think and hasn’t overheated since.

Update: I’ve replaced the head gasket and water pump. The head gasket looked fine but some of the coolant ports were clogged up. I’ve replaced the thermostat housing as that was almost entirely blocked and contained no thermostat. Put it all back together, flushed it 3 times and it held temp whil…

Did you have the cylinder head flat tested and crack tested while it was off?

No, I put a straightedge on it and it seemed ok put it hasn’t been professionally checked. The old gasket looked fine, there was no damage to the old water pump, and there’s no mixing of oil and water.

Did you check thermostat is opening ? If not that then most likely blocked radiator. Mine was, tried flushing with various things but although had flow through rad a lot of the chanels wouldn’t clear so wasn’t getting an even flow leaving a large section of rad not getting hot. Bought new rad and 20…

Overheating issues on 1.6 NB

Technical Area Engine, Transmission, Exhaust etc

Roadster_Robbie 20 December 2025 10:50 29