This is actually my MiTo, but same thing. I noticed this morning when refilling my screenwash that the coolant was well below the minimum line. I did top it up when I changed the oil a few months ago but I freely admit I've not been checking it regularly since then.
As I'm at work I've not had a chance to properly poke around it, but my initial suspicions are either the metal pipe that runs across the front of the engine (assuming the 1.6 suffers from this design too), or possibly the coolant temp sensor (as this was where it leaked on my old 1.4 Punto).
Again, at work so not checked for mayo in the oil but I'm going to assume that it's not getting into the cylinders anywhere as the car is still running perfectly fine.

No damp carpets ?

OAT coolant..so 'rusty stains' rather than blue furry areas at leak source.

Diesel not petrol?

No dampness in the cabin, yes pink/OAT coolant so will be looking out for red marks when I can. Diesel, yes.

I’d have a look on mine but the engine bay is so crammed it’s hard to see anything.

I’m not sure the Diesel engines do have the pipe running across the front?

I think they have plastic thermostat housings which have the tendency to crack, but I’d have thought you’d have lost a lot more coolant that way.

The thermostat housing was also a candidate in my head, and tbh the timing belt is due so I may replace it while doing the belt and pump anyway...

I wonder if the Bravo owners could be more help, there are certainly more 1.6 bravos than there are puntos

True, I was thinking more about packaging than application

Looking under the bonnet of mine there is not much difference to the bravo, just no space around anything. I was thinking the bravo bunch would be able to advise if there are any problem pipes, all I can see from looking at mine is that there is a top of an engine and zero chance of getting your hand in anywhere to do any work on it.

Eklipze3k said:

True, I was thinking more about packaging than application

Click to expand...

Did you ever get to the bottom of this, just in case I ever have a similar problem on mine ?

No, I've had a good poke around and can't see any signs of leaks anywhere. Seems to be about 200ml per week. In the throes of moving house/renovating right now so no time for a full check.

Well, for the last 4 weeks I've been driving back and forth from York to Huddersfield to do work at the new house, but because I've been so busy I haven't been checking the coolant levels. On my way to work this morning the temperature gauge did the thing, the car overheated, I managed to nurse it up the hill to work and parked up, stuck 2l in there

Hopefully no permanent damage, but we'll have to wait and see

I once drove my 1.3 multijet 20 miles with no coolant when the water pump seal failed and dropped it all out.

I was lucky in that it was winter and the car didn't get hot at all. (concluding the 1.3 doesn't need coolant in very cold climates, it would seem)

Obviously its a bit warmer out but its a steel block not wussy alloy like the petrol boys have, so it should be fine, the guage is not a true indication of the engine temp, the ECU manuplates the gauge reading so it doesnt move up and down every time the fan comes on. It basically holds it in the middle if the ECU is happy with the temp and will quickly shoot up to the top if the temp goes even slighly above the set upper limit.

Interesting, because it (the temp) was maxed out as I was going up hill, when I hit the top and the engine wasn't stressing as much it dropped back down to 1/2 way almost instantly. I've got the wife picking up some coolant as I could only put water in for now.

It's was preceded by a fairly obvious loss of power as I was accelerating from a 40 to 60 and it definitely felt like it was doing it slower than normal, and just as I thought that BEEEEEP high temps, turn off engine, blah blah.

I slowed back down a bit to about 45, turned off A/C and put the blowers on full/max heat, so not sure if it was any of those or the levelling out which caused it to cool back down, seemed as long as I was going flat or downhill it was OK, but the next couple of uphill stretches before work caused it to heat up again.

The route, if you're interested ...

https://goo.gl/maps/W3o1TwBbRNq9qYEw9

I'd driven all the way from York to this point before it started acting up

Was up that way only a couple of weeks ago, Wife is from Selby way.

Looks like you got a hell of a long way, probably need to keep a couple of litres of water in the boot till you can find the cause.

Yeah, wife has picked up 2 liters of concentrate for me, gonna make that up to 5 liters and keep it in the boot for top ups.

So an update on this, for a couple of days after the incident even the shortest trip (15 mins) would empty the reservoir, but it wasn't losing anything sat still. Then, as if nothing had happened, it's gone back to just losing a few ml per day. I've bought a new reservoir (in case it's cracked somewhere, as it only ever seemed to be losing what was in there), new cap (just in case), thermostat and timing kit including pump so we'll have a good poke around and see if there are any split pipes too when doing all of that lot.

Eklipze3k said:

So an update on this, for a couple of days after the incident even the shortest trip (15 mins) would empty the reservoir, but it wasn't losing anything sat still. Then, as if nothing had happened, it's gone back to just losing a few ml per day. I've bought a new reservoir (in case it's cracked somewhere, as it only ever seemed to be losing what was in there), new cap (just in case), thermostat and timing kit including pump so we'll have a good poke around and see if there are any split pipes too when doing all of that lot.

Click to expand...

Well done mate better safe than sorry. Throw up pictures if you can to help anyone else out with issue.

But its still an issue..

Defintely keep us updated