E36 BMW 3 series Coolant / Antifreeze Flush and Change Instructions Part I

* This article covers draining, flushing, refilling, and bleeding the coolant system on all six cylinder E36 3 series BMW coupe, sedans, and convertibles, including the 1991-1995 BMW 325i, 325is, 325ic, 1995-1999 BMW M3, 1996-1998 BMW 328i, 328is, and 328ic, and 1998-1999 323i and 323is. All of these cars have derivatives of the M50 engine (including the S50, S52, and M52 engines), and their cooling systems are all extremely similar. These instructions may also be generally applied to the E36 M42 and M44 engine cars (318i, 318is, 318ic, and 318ti models). * It is critical that BMW owners maintain the cooling system on their cars. The ethylene glycol in coolant breaks down with heat and age to become acidic, and can eventually cause water pump failure, overheating , and even attack the head gasket. Regardless of the climate you and your BMW live in, you should make sure the right coolant is used, at the right capacity. Got a high mileage E36? Think about flushing the system once a year. BMW specifies G12 orange/pink coolant for the E36 cars, (and not just E36 3 series but most modern post-E30 BMW models). Phosphate-free coolant must be used as phosphates damage aluminum alloys found in BMW engines. Some people insist you have to use BMW oem coolant bought at the dealer (to the tune of $25+ per gallon). I don't think that is the case, considering some BMW dealers fill your car up with the green stuff (a la Prestone) when you pay for a coolant flush unless you pay extra and specifically request BMW coolant. One thing that I cannot stress enough is that you should NEVER mix coolant types. Mixing green/blue coolant with pink/orange coolant (aka radiator fluid) can cause an impossible-to-get-rid-of brown sludge to form in your cooling system and block! The bottom line: if you open the plastic coolant cap on the expansion tank next to the radiator to find green/blue coolant, then you should continue to use that coolant, unless you are damn sure you are going to be able to flush all the old antifreeze out! Let's get started draining your BMW's coolant. For e36 6 cylinder cars, you will need 2.5 gallons of distilled water to flush the system, 1 gallon of NON mixed NON diluted BMW coolant or similar G12 coolant (unless you are going to continue to run green coolant - something you should only do if your car currently has green coolant/antifreeze in it!) to run with another gallon of distilled water for the final fill up, a 19mm wrench, a flathead screwdriver, a phillips head screwdriver, and a bucket or some sort of catch pan for the ridiculous mess you will make when you remove the engine block coolant drain plug. Some people use a large cat litterbox pan to cover more area...but plan on a lot of radiator fluid or coolant or antifreeze or whatever you call it all over the ground. First, start and warm up the car. Set HVAC/climate control to highest temperature and fan setting and run until the thermostat opens (up to normal operating temperature). I put my car up on jackstands for this. To be continued...