In the owner's manual of my 2000 civic, it states to use an oil filter with a built in bypass feature. Does anyone know why the engine needs this feature and what oil filters have it? What would happen if the filter does not have this feature?

 

Just go to your local auto parts store and as for a filter for your specific year/make/model. They'll give you a few to choose from but all will be correct for your application. They're only like <$10

 

Actually, OEM filters are around $5 What's the point in using aftermarket?
And, btw,Honda sales exactly the same filter for both my 92'(d16z6) and 03' (k20A3).
As for your original question - its a safety feature for your engine. If your filter ever gets clogged/blocked for any reason, bypass is supposed to keep the oil circulating so your engine gets lubricated no matter what.

 

They're between 7 and 8 dollars, hence the "<$10" ....smartass