I have a 2002 Nissan Altima with 148,000 miles that has engine oil passing through it and fouling up the catalytic converter. Nissan mechanic says that they can put in a used engine with 50K miles and replace the catalytic converter for between $2700-3000. Is it better to replace it or put that $ toward a new car?
How much oil is it using? How long between it starting to use oil and you needing a new converter?
It takes a fairly good-sized oil consumption problem to plug up a converter (by itself anyways-- if combined with being generally out of tune, all bets are off). If the bad converter is the only thing suggesting the need for a new engine, I’d say just replace the converter and call it good.
Even if you are burning oil, but it’s not horrendously bad, I’d be inclined to say you might still be better off just throwing another converter on there (preferably from an independent exhaust shop instead of the dealer) and hoping to get another few dozen thousand miles out of it. Depending on how long these cats last, you might end up going another 100,000+ miles before you break even on buying converters versus buying a new engine. (Although I perhaps would not try this strategy if you’re in a strict emissions test state).
With large sums of money, either replacement car or fixing I would pay for a 2nd opinion.