my sis myvi 1st gen...
today realise the coolant meter go up when stop but will go down when driving...
check coolant tank, coolant still at "F" level....
what possible cause it?
thermostat?
fan?
pump?
happen after last night when go buy somehing,
let the car on with aircon (cos my mom stay inside)...
and today this happen....

Coolant still at F meaning spare tank still in full? I mean what kind of full? Some ppl fill full for spare tank some fill until the designated line

Have you check and open the radiator cap if the water is empty or full once the engine is warm to touch?

If guessing probably is thermostat is jammed
Or fan is not running during idle due temp sensor faulty ,when car is moving water temp gauge down because AC is on ? Or when moving more than 30km/h outside air help to cool the radiator

If you want to know if the fan is spinning turn on the AC the fan should be spinning very fast like you can imagine going chop off your finger

This post has been edited by zuozi: Oct 20 2024, 09:03 PM

during temperature high, listen to open bonet
got boiling noise or not. and the waters are dancing bubble

Is time to replace water pump, coolant piping, hose, thermostat, radiator cap,

spare tank is until F
but inside radiator dont know...
as scare the hot water burst out...
maybe the fan working as the aircon still cold...
also want to know what is the market price for water pump/fan, etc....

this morning try open the cap(but engine is cool), water not full...
i put some water and try accelerator, the water overflow...(pump ok?)
but it was clear not red/pink, normal?

fan spin when i on the AC, (fan ok?)

not dare to open when hot...
not expert in car fixing...

pijak gas water shoot overflow & bubbles?
worry gasket not seal full liao

pijak gas water overflow...
no bubble cos engine still cold...

If you want to DIY, start from something simple like changing the radiator cap. If cap is fault and cannot hold pressure, boiling/bubbling happens. Otherwise, just send to mechanic.

not gonna diy, not expert...
will send to workshop..
just want to see if can know what wrong before send to workshop....
scare workshop cincai say change this that which not related....

Usually when acceleration by right the water is going down even thermostat not fully open yet, when radiator coolant is hot the cap is still open the fastest you acceleration 4k/5k RPM they still manage to keep going down until you release acceleration only then the fluid is slowly boiling out from radiator cap, probably you have gasket failure for common scenario if thermostat already open but water keep blowing out when acceleration

The other sign if radiator cap faulty the surrounding have those rusty water marking/residue since your sister car no longer have proper expired/over life span/antifreeze

Also Possibility your thermostat is jammed i mean top is hot bottom is cool, once thermostat is open hot water travel top slowly cool by fan via radiator fins/water tunnel then only go down basically water pump keep pulling bottom radiator water to engine i mean hot raise cool fall concept if you faham if thermostat is jammed they keep stuck unable smoothly travel the water effectively possibly scenario

This post has been edited by zuozi: Oct 21 2024, 10:15 PM