Fill the car with coolant and check for leaks. You might have to wiggle it side to side to get it to break loose. This project was done on a 2002 325xi but the cooling system is pretty much identical on all E46 models from 1999-2006. The following day check the coolant level; you'll most likely have to add some coolant to the expansion tank. Loosen the water pump pulley bolts prior to removing the alternator belt but don't take them out all the way. A few things to note about coolant is that it is sweet tasting and highly toxic, so it can end up in the dog's stomach pretty quickly.
. Use a screw driver or something similar to keep the tensioner pre-tensioned while you install the belts. If you ignore a small coolant leak long enough, you will run out of coolant, which leads to an overheated engine and other serious, but highly avoidable, problems. Cars with a hydraulic tensioner most of the time will only need a replacement pulley 11281748131. The rest is pretty self-explanatory. Pull out the clip that holds the expansion tank to the mounting plate. This article can also be used as a guide for replacing the water pump, thermostat, fan clutch, radiator or expansion tank.
Install the radiator back in the car. Once the fan clutch is off the water pump pull the shroud out together with the fan. Disconnect the upper radiator hose from the expansion tank. Unclip the transmission oil cooler from the expansion tank mounting plate, pull it out. Unclip and remove the lower radiator hose from the thermostat. Using a 32mm wrench and a fan pulley holding tool remove the fan with clutch by turning the nut clockwise.
Mount the expansion tank plate to the new radiator. Push the top of the radiator back and pull it out of the car. Start the engine, open the bleeder screw and let all of the air bubbles come out. Remove all of the bolts that hold the thermostat to the engine. The video above shows you where the coolant reservoir, hoses and connections on your 2002 325i Base are located and the steps needed to fix minor leaks. All pictures and manufacturer information is for identification purposes only.
Clean all of the water pump and thermostat mating surfaces and reinstall the thermostat and the water pump. Do not use any sealants on the water pump or the thermostat. Disclaimer: All efforts have been made to keep the information on this site as accurate as possible. Reconnect all of the hoses, connectors, install the expansion tank. Remove the coolant hose that connects to the bottom of the expansion tank mounting plate.
You are going to reuse the level sensor in the new tank. In many 2002 325is, an anti-freeze leak can cause the temp sensor to record high engine temperatures. Remove the drain plug on the passenger side of the engine block and drain the coolant out of the block. This picture is just to show you how the belt goes back on the engine. Remove the radiator drain plug and drain the coolant. Be sure to lubricate the water pump o-ring with some fresh coolant prior to installation. Remove the expansion tank off the expansion tank mounting plate by pulling up on it.
Remove the radiator mounting screw. Engine lifting bracket will have to be removed as well. Engine coolant which is also called antifreeze or anti-freeze moves through the inside of your 325i's engine and keeps it from overheating. Do not over torque the thermostat bolts. Disconnect the coolant level sensor wire, turn the sensor about half turn and pull it out of the tank. Leaking coolant is one of the more common types of fluid leaks on 325is. Remove the alternator cooling duct to gain access to the coolant level sensor.
The fan clutch has a reverse thread so if you are facing the car turn it to the right. Remove the water pump pulley, remove the 4 nuts that hold the water pump to the timing cover, insert the bolts that were used for the pulley into two threaded holes in the water pump and tighten down the bolts gradually until the water pump pushes out of its housing. Using a 15mm socket turn the alternator belt tensioner until the belt is loose enough to be removed. Start out by removing the air intake scoop and the air filter box. Unclip and pull off the small hose that connects to the bottom of the expansion tank.
Use new o-rings when installing it back. Remove the clips for the fan shroud. Coolant can leak from the reservoir or from the hoses, in 2002 325is with the 2. Disconnect the electric fan 4. Always protect yourself with safety glasses and gloves when working with the coolant on your 325i. Disconnect the temp sensor in the lower radiator hose.
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