Would a 2000 (W - 70k miles) Mk3 with FSH automatically have had the pre cat taken out?
Been to see one which i'm contemplating buying but the owner is unable to verify whether this has been done or not.
Thanks
If he doesn't know then assume they're still in there. Best way is to pop the O2 sensors out and have a peek into the chambers, if they're not there then it's either very good or very bad...
Pretty much, yeah. Personally if the car was running fine (no funny noises or lack of pull in the midrange) AND I could see that the precats were definitely there from the top O2 view, then I'd be happy enough to buy the car and strip out the precats myself the following weekend.
The link above covers the pre-casts in isolation very well.
However it misses out a HUGE related issue - oil consumption.
Excessive oil blowing by piston rings is a common problem all by itself, caused by a poorer piston ring design in early (<03) 1ZZ engines.
This oil consumption can be kept in check for weeks, months, maybe even years in some cases (when combined with thicker oil). However oil in the exhaust stream is likely to initiate the breakdown of the pre-cats, and (due to the issues mentioned in the above link) THEN make the situation a lot worse very quickly.
The engine fails through lack of oil (through burning it all) in both cases.
Best practice is to remove pre-cats before any oil consumption issues occur, and to always monitor for blue smoke coming from the exhaust (a bit of white is fine, especially when cold).
If you notice blue smoke, then you just need to keep on top of your oil level as best as possible.
There's an abundance of info available over on mr2roc via the search function if you're interested!