shadowrose45

i just bought a 2008 Scion. It overheated ren mins from the lot. It also has no heat.

the dealer replaced the following:

thermostat
hoses
water pump
heater core
radiator

the car continues to overheat. Mechanic says he bled the radiator and he pulled the green antifreeze and replaced it with the pink.

apparently, the heater now works, but it's still overheating.

It has 225k miles on it.

any ideas? The mechanic is at a loss. He has replaced each thing that controls overheating as far as I know

samatman

I'll take a stab at this...

The fact that heat returned after replacing (so many) components means coolant probably wasn't flowing at all initially (thermostat/water pump, whatever).

Green should never have been in this car. There's only two things I can think of:
1) fan(s) on radiator not spinning up appropriately.
2) clogged coolant passages from poor servicing / improper fluid.

udelslayer

Did he say there was any stop leak in the coolant? Do you see bubbles in the radiator when the car is running (cyl pressure being pushed into a water jacket). Air pockets can cause overheating.

If the heater is working, I'd think the coolant is circulating but it can take a couple of cycles to get all the air out of the system.

Green can be used if its not mixed with the other stuff, but not for the long term. If Dex-Cool (usually orange) was put in there, it will coagulate with other types and cause all kinds of hell. You dont "bleed" a radiator, you flush with water. Sitting idle it will take a long time to reach temp to turn the fans on.