Car: 2003 Mercury Grand Marquis 103k miles
Whenever I'm at a stop light, steam is coming through the hood. It does not overheat and there is no sign of any coolant loss. I want to say it's coming from the vacuum booster because it's the direction of the steam but I am also thinking it's a heater hose that has a leak. Are there any hidden heater connections behind the block?
You might want to pressure test the cooling system. You may have a pinhole leak in a hose that only leaks when the cooling system is pressurized.
Whenever I'm at a stop light, steam is coming through the hood. It does not overheat and there is no sign of any coolant loss. I want to say it's coming from the vacuum booster because it's the direction of the steam but I am also thinking it's a heater hose that has a leak. Are there any hidden heater connections behind the block?
There's a giant vacuum hose that goes from the booster to the engine, there's no coolant there.
There's an entire heater core beneath the dashboard. You would notice coolant on the floor if it were leaking from there.
Is your radiator cap still OK? Radiator caps wear out over time.
