Hey all, 90' 240 ran low on coolant, res was empty and motor was H O T, I have replace the thermostat, top hose and coolant. This did not fix the disappearing coolant upon further investigation I felt maybe a bad head or gasket due to some milky stuff under cap, my mechanic says nope,,,so I have since found coolant coming off the bell housing and onto exhaust, so I replace heater core hoses, thats gotta fix it. Nope still steamy but now looks like its wet in between injector and valve cover but it was dark when I tested.
Any ideas out there!

 

I have an 86' 240 gl and have had an ongoing issue very similar to yours. I ended up replacing the reservoir cap. I suspect the old caps valve had worn out, causing it to release pressure and coolant even on short in town trips. In my case it was fairly easy to diagnose where it was coming from though. The underside of the hood showed where the splatter was coming from. The coolant had dried in a whitish color. I have gone on some drives and don't think I am losing coolant anymore. Have you found anything else out since posting?

 

Found that the heater core hose that runs to the head had a split in it, 7$ hose but had to remove injector to do repair!

 

I am reviving my 92 240 wagon from a 1 1/2 year slumber (head and cam issues). I noticed that when I rev the engine I get coolant spraying from under the intake manifold. Will check the hoses down there. I'll probably remove the throttle module (???) and clean it. I think that would give me enough room to reach the hoses.