My 1990 bmw 535i was overheating, found crack in pastic part of radiator and thermostat. a month later the water pump was leaking i replaced that. now it is losing anti-freeze what appears to be from the overflow hose by the firewal on the passenger side and will over heat if i dont fill it every morning.

If your 2012 BMW 535i is losing all of its water but not overheating, there could be a few possible causes:

1. Leak in the coolant system: The coolant system of your car may have a leak, which is allowing the water to escape. This could be caused by a faulty radiator, a leaking hose or a cracked engine block.
2. Evaporative loss: In some cases, the water may be evaporating due to high temperatures. This is common when driving in hot weather, and it can be caused by a malfunctioning pressure cap or a faulty radiator cap.
3. Leak in the water pump: The water pump may be leaking, causing the water to escape from the coolant system.
4. Leak in the head gasket: A leak in the head gasket can allow coolant to leak into the engine oil, causing the water to disappear.

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Sounds like a leaking head gasket. The head gasket can allow coolant to leak into the cylinders, and compression to leak into the cooling system.

For a coolant leak you need to check all the hoses and fittings by radiator, heater core, expansion tank for leaks and/or integrity. Also make sure that your water pump is not leaking along with radiator cap and thermostat body. Overheat condition has no effect on battery - if it does not hld charge it is because it is chemically worn out and needs replacement. Until you correct water loss, have extra water in car at all times and run your heater full blast - windows open!!!!

Quite easy job.

Locate top radiator hose, follow it to the engine, undo the hose. What it is connected to is the thermostat housing. Undo 2-3 bolts connecting it to the engine block. Lift out the thermostat which is a diamond shaped unit.

Replace it with a new one. And refit the pipe. You might need to bleed the radiator in case of any air bubbles. Run the car with the radiator cap off. Top up the coolant level until the fan kicks in twice (20 mins).

Hope this helps and please vote for me, thanks.

Flush Your Radiator

its hardly one of the frost plugs leaking at the back of the engine is it...due to the pressure when the thermostat stoped working,,,probably a long shot though,,,,

it's head gasket or water pump, or if you are lucky the thermostat is broken.

Hello Ranger Joe, eight months and two radiators is very uncommon. Question, Have you visually confirmed the leak in the radiators or is the leak near the hose connections? Replacing the radiator, cap, water pump, & the thermostat leaves only two others, the hoses and the engine block/heads. Far fitched will be something or somebody poking holes in the radiator.

It could be your head gasket.