My friend Sean's M3 also needed a little love when it comes to the cooling system. Sean wants to pick the car up and take it home. Our plan was to replace the radiator with a Mishimoto Z3M three core unit and a Spal 16" fan. However we ran into a few quirks. We also replaced the thermostat and thermostat housing. We upgraded the water pump to a Stewart high flow unit to improve performance. We also used some new billet radiator stays and a European radiator cover. To cap things off we threw in a Radium Engineering billet expansion tank.

This is really coming up as a beautiful build. Ultimately the BMW decided to put up a fight and we didn't get everything done in one video. Our goal was then to get some proper routing for our oil cooler lines and then flush and fill the coolant to get the M3 on the road.

I got to use my AHP AlphaTIG 200X welder and some riv nuts on steel stock to make the bracket for the expansion tank. Then we mounted the remote oil cooler and created the custom lines I mentioned. We used JEGS -6 AN hose fittings and JEGS -6 AN hose to make the lines. In retrospect the hose was fine, but the fittings were hard to use compared to others I've tried such as Fore Innovations. The fitment we got seemed poor and we had a hard time doing the job.

When the car was fired up we used detergent to flush the engine and then a nice rinse of water. We used a vacuum based cooling system leak detector and filler. This is a pretty cool tool. Finally we used some BMW OEM coolant and Liquid Chill from Mishimoto.