2000 BWM 528i coolant leak

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.

Look in the radiator for the presence of oil or bubbles. See if water is dripping from the tail pipe. All these indicate the engine is burning the coolant. Look for a blown head gasket or a cracked head.

You might want to go to an AutoZone they might do it for you for free if you ask them for help. Answer right fender side, cap says brake fluid.

fluid to what

its sealed gearbox but there is i think a level plug on the side of the gearbox but it has to be checked in specific way ie oil temp etc you need a workshop manual to find out the correct procedure

P1188 is a fault on the pre-cat o2 sensors (reading out of scale)

Most common problem is an air leak into the engine (failed gasket or vacuum hose) or faulty air flow meter. I would not replace the o2 sensors until the other things have been checked first (10 years as a mechanic I have only ever replaced 2).

Check your engine for sucking noises, broken vacuum lines, etc. otherwise a mechanic will need to read the live data from the Air flow meter. Bosch AFM unit should hit around 500 on that model at full throttle.

firstly, check coolant, add to required level. a fluctuant temp gauge usually means there is a migrating air pocket in the system somewhere. the question is, is this a new air pocket due to currently leaking coolant or is it a pocket leftover from the t-stat replace way back when that was never completely bled out? if the coolant already seems at the required level, then the system needs to be bled again. if this does not solve it, then i would again suspect the t-stat

You might want to check the outside ambient temperature sensor, located in the right front wheel well, when these become damaged, the dash temp reading might say somewhere around -44degF if this is the case replace the sensor and things should be okay.

Pressure test cooling system to determine origin of leak. Radiator and coolant reservoirs are common problems. Vehicle is very difficult to purge air from cooling system and may take multiple times of idling until thermostat opens. Sometimes help to rev engine to about 2500 rpm 5-8 times to help build heat and move coolant through system. Must have heater on while performing this task.

you'll want to make sure that all the air spaces have been removed from the coolant system. Sometimes you have to add coolant thru the upper radiator hose.

What also works is to install a prestone flush kit. It will allow you to run water under pressure to the entire system.