Welcome

Welcome to EJ Coolant Mod. This is where we give you the details on how to gain better reliability in your EJ based engine.

First, you should be running a high quality 5w40 or 10w40 engine oil. The owners manual says 5w30 which is proven to be too thin when hot. The 5w40 protects the bearings better when hot. This is helpful even for stock, unmodified, cars. We stock Motul 8100 5w40 in 5L jugs and prefer that. A more cost effective alternative, which is also great oil, is Rotella T6 5w40. It’s spec’d as a diesel oil, but does a great job in the EJ engines all the same.

Second, consider adding the left head coolant passage modification we offer. This increases flow around Cyl 4, which reduces chances of knock.