Hey everyone 
 
On the way back from the NSW mr2 meet tonight. I started having over heating issues where i noticed the temp gauge was maxed out. I didnt notice the gauge being at that height at first but what made me aware of this was that after driving for a while, my heater wasnt giving me warm/hot air even on the highest setting. It was then when i noticed the temp gauge. I had to drive about 2ks from when i noticed the temp level to a carpark where i could shut the engine off. Once parked, it was hissing and doing the typical over heating dance. First thing i did was run to the petrol station and bought some coolant and waited for the engine to cool and then topped her up. After all the collant it lost/was spitting out in the car park...it only lost maybe all of 2L. This has me a little confused as there was a substancial amount of coolant left in the system so it couldnt of been a lack of coolant/blown radiator issue. Anyway i had my father come out to assist in my trek from the car park to home. After the car was topped up with collant and was cool, i began the drive home...unfortunately the shortest route was through galston gorge  I made it half way through the gorge with out an increase in temp however through the other half it began rising, to the point on exiting it over heated and shut it self off. However as it increased in temp there was a metallic rattle that increased in volume coming from the engine bay....would anyone know what this is?, it has me very worried! From this point onwards i have hooked up a snap strap and had my father tow me to my local mechanic, where we have left it until tomorrow.
 
One thing i noticed was that the radiator wasnt hot nor warm which im thinking means that the coolant isnt being pumped to it to be cooled. This seems to me that it is possible that the Thermostat has given up the ghost on the way home or that there is a blockage within the cooling system, which is possible as i scraped out some light pink sludge from the radiator pressure release opening whist doing some fortnightly maintenance earlier today.  
 
What are your opinions on this and is there something im missing or dont know about that is causing this?
 
Thank you in advance
 
Declan 

Hmmm, sorry to hear it mate.
If the radiator doesn't feel like it's been doing anything, it could well be the thermostat.

Thanks Rob for such a quick reply.
 
Thats was my best guess but am unsure as it was just such a sudden issue. I guess its about time i had a mechanical issue in my 10 months of ownership haha.
 
With this over heating exercise i also found that the oil that i thought was coming from the gearbox that i was talking with you about earlier tonight was in actual fact coming from the purge tank over flow. Not sure if this has something to do with the over heating issue i have.  

I'm so sorry this sounds ugly but
 
No heating = no coolant
 
no coolant could come from a leak in the system or being forced out due to pressure.
 
I'm guessing a head gasket.
 
The oil may not be cloudy, but can you smell a sort of unusual sweetish smell (as coolant goes out the exhaust, regrettably..)
 
 

Cheers Nick
 
The thing is i lost all of 2L at most. Having my father driving behind me at the time, he said there was no mist coming from the exhaust which is generally what it looks like when coolant is being dumped out the exhaust. So fingers crossed its not a head gasket. 

Sound like the same issue that I am having. I'm thinking it's either the thermostat or the waterpump. If your heater is blowing cool air it could be because that liquid isn't circulating properly.

Any history of cooling problems?
 
"If the radiator doesn't feel like it's been doing anything, it could well be the thermostat".
+1
The first thing to check. Put it in hot water on a stove to test it.
Should open about 85 centigrade.
Good luck.

sorry to hear this, as the cooling system is sually good on the mr2 unless its been neglected..
you said there was oil coming from the reservoir over flow??? or was it red coolant you though was oil..
 
boiling coolant will evaporate as soon as it spews out from the engine so saying on 2 litres was lost is a gamble at best. and if its anything like i had the coolant will just boil out the reservoir and dissapear
 
the radiator isnt warm because theres no coolant in it , so you have lost more than 2 litres i think
and driving 2kms after finding an overheating problem wasnt the best idea either.
in my case i had an headgasket issue, and coolant was coming out the oveflow tank until it got to a point where there want any coolant left in the block and then the temp. gauge would skyrocket, this was taking about 45 mins to happen, so i wasnt aware of it straight away... there ended up being a small crack in the gasket which would slowly leak and eventually cause overheating in my case..
 
either way make sure the car is filled PROPERLY with coolant (13.6 litres afaik) and then check for issues, i would replace the thermostat as well to rule that out

The car hasnt had any cooling issues in the time ive owned it nor with the last previous owner. The way i gauged that it was about 2L lost was by how much i put back in before it over flowed. I am unsure of where the oil is coming from...my mechanic assured me it wasnt coming from where i thought it was. So thats still a mystery, though the oil i found was quite watered down compared to engine oil. This has me wondering was this possibly an early sign of this cooling/leakage issue. 
 
My mechanic has had a look at it and suspects that it was indeed the thermostat that went but has now found that gases are leaking into the cooling system as the coolant was foaming up and continuously over flowing through the in-fluctuation of gasses in the system. So its a warped head gasket 

Well mine overheated the other night (after a hard run mind you) and it was air the in system caused IMO by a faulty radiator cap. Check your radiator caps guys!