keeping it cool

[twoninety]

hey everyone !,

im new to this place.. :)

here it goes...

i have a 08 yaris with 290,000km (180,000 mi)

today i was doing some cleaning and noticed the overflow coolant reservoir was almost empty. keep an eye on things under the hood and usually reservoir level looks good

hmmm ?

so i filled reservoir to the max mark ( premixed pink/ toyota) coolant, and went for a drive

kinda cold here in toronto, around 3c (40f) but eventually , while the car was in my outdoor garage, coolant temp rose to around 95c (203f) ( obd data), then the fan kicked in.

also, to the touch, the top hose to the rad was quite warm, but the bottom hose was much cooler

eventually, the bottom hose got quite a bit warmer ( thermostat opened ), when coolant temp went over, approx, 90c ( 194f)

fluid in reservoir stayed at same level as before- at the max mark

went for as drive, and coolant temps came down to around 80c (175f) after a few minutes at low speed driving

hmmm

i did notice some steam , that appeared to be coming from the inside top of the rad, just kinda under the top rad hose

a rad leak maybe ?

chemical sealant solution?

or ?


given all the above observations/ info, any thoughts on whats going on.. why reservoir was previously empty?

*** dip stick and under oil cap looked fine, clean oil. and removing rad cap ( when cold/ cooler) fluid looked okay. tried to add some coolant but only took a couple of ounces before overflowing...
power/ driveability is good/ normal..


any thoughts/ ideas as to whats going on?

much appreciated :)