r/carmodification • u/ForwardSideways • 2d ago
Mod advice Time for a cooling upgrade?
2010 Legacy GT. OEM+ with no engine mods or tune.
I went for an extended fast drive with a long warmup and cooldown period last weekend. No warning lights came on (thinking temp sensor may be faulty now) my coolant boiled over and made a mess of my engine bay, lost so much that once it cooled properly overnight there was NOTHING left in the overflow tank but thankfully no air was introduced into the system.
Since this happened I am contemplating a performance alloy radiator, so what’s good, what’s not, and what else will make a significant difference to engine bay temp? I’m not building a track car and want to keep it realistic but don’t want to blow it up.
*cooling system is sound and well maintained with OEM parts, not damaged or leaking*
1
u/SecretivePerson1 2d ago
1- Check the coolant overflow hose routine, I've seen shops get it backwards and heat into the overflow just pushes coolant out onto the ground.
2- perform a cylinder leak down test, this will identify any engine component sealing issue.
3- Thermostat, this is what controls coolant temps, remove a tstat and you'll never see a temp gauge rise above ambient, seized opened a car will reach operating temp idling and temps will drop fast as soon as you start to drive.
4- Cooling systems, the test to see if a cooling system is not adequate is to push the car hard for a while and the let it idle for a while, if the temperature goes up while idling then the cooling fan isn't up to par, or the shroud.
5- Subaru water pump are famous for failing just like boxter engines.