Cooling System Maintenance
Bill Buckwalter '98 1.9

Jack the car up first The objective here is to get the car far enough off the floor to make crawling under it with a drop light and catch pans easy. It is important to be safe and to have the car level for complete coolant drainage.	Z3 dipstick detail Note the coolant hoses and coolant shut off valve were removed. This opens up that quadrant of the engine bay for easy viewing toward the back driver’s side of the engine.	happy idiot My wife stopped in to call me to dinner and went back and got her camera. Note there is enough room in the engine bay for the 4 cylinder engine and a fat ass. It also makes working back along the firewall much easier. From this position one can see and work on the hoses connected to the back of the head.
Coolant manifold location, view from top This shows the inlet hole in the block for the plastic coolant manifold, located at the bottom end of the chop stick. It needs to be cleaned of all residue before installing the new manifold and O ring. Be sure to grease the O ring, it is a tight fit.	Accessory removal, side view This illustrated the standing room in front of the engine and how removing all the gingerbread on the front of the engine opens up things for access. Note the blue tape labels.	Accessory removal, front view Note the top half of the intake and the power steering pump with bracket were unbolted and set aside. This was to avoid removing the throttle linkage and power steering hydraulic lines, minimizing the work of adjusting the throttle linkage and coping with power steering fluid on reassembly. The 4 cylinder motor in this car has the room to facilitate these kinds of short cuts. Just have plenty of soft rags or towels handy to sit things on in order to not scratch paint. Some mechanic’s wire (or coat hangers) comes in handy too for holding things off to the side.
Z3 Coolant manifold This is the manifold that has the history of cracking. There is another one on the front of the engine that is reported to not have the same problem. After twisting and turning this one to fully seat the O ring in the block I used thread lock to hold the two bolts in place that go through the brass rings in the flange plates along the bottom of the manifold. Note the rear brass ring sits in a slot. I figure that allows for thermal expansion, so I cranked the bolts down tight.	hose inventory match As an amateur enthusiast I cannot stress enough the significance of verifying all the right parts are on hand before starting the job. Make a project out of it. Look at them carefully, and when you extract a part from the car, compare it to it’s new brother. Note I left the short “S” hose on the heater coolant valve assembly. This was to help me assemble things correctly with minimal puzzlement. Plumbing gets a bit convoluted back there by the firewall.