Just about to purchase an '01 Highlander with a 6 cylinder. I've heard two stories that is IS and it IS NOT an interference engine. Anybody able to clear this up for good?

Thanks.

 

VVTi is interference

 

Can you substantiate that claim in any way?

It seems a lot of trouble to go to by cutting reliefs for the valves in the pistons. If the valves can hit them anyway.

And what definition of interference are we talking about? Like if the timing belt/chain snaps you're screwed? Or if the VVTi system fails(mechanical failure, ECU failure, causing the the high rpm lobes to be used at low rpm)? Or would both have to happen? Seems like both is more likely. Or maybe a more suitable semi-interference designation is needed...possibly. Maybe there already is such a thing...

 

https://en.wikipedia.org/wiki/Toyota_MZ_engine

They feature cast aluminium pistons with an anti-friction resin coating (moly) and valve depressions that decrease the chance of valve-to-piston interference in case of timing belt failure on motors without VVT-i. They also use steel rings, smaller-diameter shot-peened rods, and a forged steel crankshaft.