[pierreandre]

Good morning

I would like to run my diagnosis by the experts.

Symptoms:
1. Engine takes much longer to heat up to operating temperature. This has been going on for a week or so.
2. Once heated up, the temp gauge keeps on climbing to just below the red line. I first noticed this on Saturday.
3. When holding the two hoses leading to the radiator in your hands, they only start heating up when the temp gauge is close to the red line. At this point you can feel and hear the water boiling in the hose.
4. The overflow bottle's level has been constant for a year, but the radiator did take about 1 liter of water.

I think its the thermostat, but wouldn't it be either stuck in the open or closed position? The symptoms are a bit confusing to a noob like me.

[4ePajero]

I suggest you replace the thermostat and coolant (not water!) to start off with.

If the problem persists, you will have to look at the radiator, hoses and coolant pump.

[pierreandre]

Sounds like good advice. Now if only Mitsu had thermostats in stock

[pierreandre]

Finally got my thermostat

Now to fit it and replace the coolant. Will be following 4epikanini's writup and I hope I don't get it wrong. Any suggestion on what type of coolant to use?

[Davidvan]

Hi Pierre,

I had similar symptoms as yours on my Paj, found the temp gauge on the instrument cluster to be at fault, appears to happen on the older gen3's, temp is erratic and all over the place, then hot and then cold after 10 minutes, but all was fine. Small board behind cluster has problem on solder points or may need replacing. Search for this, are a few posts here somewhere, also a T piece plastic join which gets old and gets fine cracks, under vehicle, not sure where exactly, and had a prob with that too, Mitspro sorted that out for me.

[pierreandre]

They new thermostat is in and everything looks OK.

There was definately a blockage or airlock somewhere in the system as well, as the heaters wouldn't work either. The water in the return pipe to the radiator would be boiling, but when draining it, the water from the radiator would be cool. After flushing the whole system four times, the propblems went away.

This is the procedure I followed to fill the radiator. Its a combination of Marius' writeup and the workshop manual.

• Park nose up.
• Remove both air bleed bolts. This is really important, as failing to remove them will cause air locks.
• Fill radiator until the first air bleed hole overflows. Close it.
• Continue filling until the second hole overflows. Close it.
• Continue filling while squeezing hoses. It shouldn't take much more fluid.

Note: I did not remove the two drainage plugs from the engine. When filling the radiator, it would only take about three liters, so I filled it with pure coolant. I assumed there was just pure water left in the system after flushing it so many times.