Hey Guys. Got a bit of an issue with overheating on a GT Turbo Mr2. The previous owner had the radiator removed and flushed, new coolant and system bled properly. I drove the car for most of the day without any problems and then all of a sudden when I got home after a drive from the city the temperature was almost in the red. The coolant reservoir bottle had popped its lid and coolant was all over the back of the car. Not happy to say the least. But here is where it gets strange. The Next day i topped up the radiator spout with water and went for  30 min drive and.......nothing, held normal temp just fine. Any suggestions as to what caused it to overheat originally and be fine the next day? The only thing i can think of would be a sticking thermostat, but I'm no expert with these cars (its all backwards and new to me)
Any help is much appreciated
Thanks Guys

If it lost a bit of water and you toped it up, i would bleed it again, and to rule out that it wasnt bleed properly by the previous owners mechanic which is very common.
 
Do a search if you dont know how to bleed it properly, with the clear bleed hoses under the front bonnet on the radiator and the heater plus rad cap.
 
Could be thermostat, there not expensive or that hard to get to so maybe do that first, again to rule it out, then bleed of course.
 
Were you driving most of the time or start stop trafic or lots of idle'n? if driving then shouldnt be the thermo fans not turning on ect. 

Also the factory temp gauge isnt liner, as in it wont move up and down exactly as the water temp does, it will up to a set point in the middle, as the temp increases a bit it will still stay in the middle, untill it goes up past a set temp then seems to spike up to near hot.

Thanks for your help, much appreciated. I took the car out for a run just now and it didnt overheat even though I was giving it a bit of stick. But.... when I got home I could hear a bubbling noise coming from the top radiator pipe under the engine cover. Its also dropping coolant from somewhere at the back of the car. Im confused by all this, but the car is going to Al Palmers workshop on Tuesday with a long **** list of things to do. hopefully they can sort it out.

loosing coolant from the back of the car? from the coolant reservoir?

any white/grey coolant marks on the neck of the radiator filler, as it turns the first corner (the neck, not the MR2). That is a common place for a crack allowing coolant to get out and air to get in..
 
Naturally, once air can get into the system, the MR2 (having the most complicated fluid mechanics ever invented for a car) has problems deciding how to tell you what is wrong.
 
Otherwise it could easily be a head gasket.
 
good luck

the water isnt coming from the overflow, its more towards the centre of the enginebay. Ill check the Radiator neck tomorrow. I dont think its a headgasket, I cant see any water in the oil (going off the dipstick and oil filler cap). The bubbling noise in the top radiator pipe is a bit of a worry though. Hopefully the lads at the workshop can sort it out on tuesday

Regrettably I didn't see any water in the oil either, but when the car quickly thereafter started to exhaust coolant and and in fact inhaled so much of the stuff that it wouldn't start in the mechanic's driveway, we started to suspect that something was getting past the head gasket..

Whereabouts are you located?

If the thing is leaking from a central position, Check your top heater hoses, they are a known issue and can fatigue and crack. They are visible right up against your exhaust heat shield on the front firewall and they go to the water jacket, right where the sensors are.