I've been having a problem with my 2007 Rav4 2.2 D4-D (no dcat) for about 6 months now, where on long journeys I lose coolant. I'll lose nothing on my day-to-day commute to work (10 miles, 30 minutes each way). However if I don't check it for a couple of weeks I'll find that I've lost a small amount.
On longer journeys I can lose a lot. i.e. a 100 mile trip a couple of months ago I lost about half the tank each way, and over 440 miles this weekend I put almost 1.5 litres into the tank to keep it around where the word Full is. (I had stopped half way home and had to wait a little while for the engine to cool down a bit, the coolant was at about 1/2 way, topped it up, drove another 100 miles home and the next morning the coolant was below 'Low').
There doesn't appear to be any water in the oil / oil in the water, there's no smoke from my exhaust that I can see and not really any oil consumption that I can notice, so I don't think that it's due to the fault mentioned on the forum requiring a rebuild.
The car went for a Service with Toyota who told me that I was losing coolant from the water pump (I hadn't checked the levels before it went in). I've had the water pump replaced by a local garage as I couldn't afford Toyota's engine out price for this. I have also had the Thermostat and Radiator cap replaced, as the local garage found that excess pressure was building up in the header tank.
It does seem that the pressure is lower since the thermostat and cap have been replaced, however it does seem that coolant is blowing out of the header tank.
Sorry about the essay, but wondering if anyone has any ideas as to what else could be at fault?