So, it's been nearly 3 years since I sold my Punto, and I managed to pick up a 51 Sei Sporting for a very good price, so good in fact, I felt like I stole it.

Anyway, there was no record of a cam belt and water pump change, and with only 61k on the clock, I could pretty much guarantee the belt in there was the one fitted by FIAT, 14 years ago...

So, apart from putting the cam belt pulley on incorrectly meaning the ignition was 120 degrees out, there have been no issues...until now...

I noticed there was a lot of gunk around the water pump when I changed it, so I decided to flush out the system, and refill it with a fresh anti-freeze solution.

So, as the system was already drained because of the pump, I just filled it up with water and added the rad flush solution, left the engine running for (up to) 30 mins, and popped inside to make a brew.

I stuck my head outside to check on the yellow beast as it was running, and noticed the water/flush solution in a weird negative waterfall effect, spraying the underside of my bonnet, then continuing downwards to wash my driveway. The pipe had split under pressure behind the thermostat, and the rad fan hasn't turned on. The 30A fuse hasn't blown, and the fan is free spinning. The rad seemed cool to the touch whilst the rest of the engine was hotter than Satan's tezzers.

So I took the temp sensor and thermostat out, both were gunked up. Tried a resistance check of the sensor, stuck it in some hot water and the resistance dropped, but not as much as I'd have expected. As for the thermostat, I threw that in some boiling water, and nothing...

It's the MPI 1.1 engine, so I believe the fan is switched on by the ECU, but that is pretty much it to the extent of my knowledge of this engine. So I'm just asking for other people's opinions?

It feels good to get back under the bonnet of a Fiat, my Astra and Focus don't go wrong, I was getting bored...

Sounds like the thermostat was the issue and fortunately you had a weak point to allow the pressure to escape, that has Probably saved your head gasket.

I would replace the hose and stat, flush the entire system with a hose then Refill with coolant and you should be good

Done. Picked up a new thermostat and temp sensor for the costly sum of £13 + VAT. I love Euro Car Parts!

I cut the hose back about 15mm as there was plenty of excess, flushed it through with rad clean and then water, topped it up with coolant and she's working fine. I had to monitor the temperature on my OBD reader, the rad starts to get warm at about 88-90, and the fan cuts in at 97, then off at 93. I know it's not perfect but it will do!

Next job, oil change, brakes and pads all round, springs to be replaced then I'll be cutting the paint back with some G3.