Which Catalytic Converter Should You Replace First On A 2003 Lexus ES300

Question:

If I was going to replace all three catalytic converters due to them being almost 20 years old, assuming they are all pretty clogged, which should I replace first if I can only afford one at a time? Or is it bad to do that? Should I do all three at same time?

asked by: Xavier

Expert Reply:

It is the best idea to replace all three at once. However, if your budget won't allow for all three at the same time considering it can be pretty pricey, then the front cat would be the one to replace considering the front cat is the one that takes the bulk of the emissions load.

The Magnaflow Stainless Steel Catalytic Converter # MF37103 you referenced is a great choice and is California Air Reduction Board compliant.

Another great choice is the Magnaflow Universal Catalytic Converter # MF447104 which is also California emissions compliant, and is a universal fit.

expert reply by: Bryce D