Howdy, this is my first post, here but I hope some Celica genius out there can help me narrow down a noise before I begin tearing into this thing. We have a 1991 Celica GT m/t with the 5sfe. This block only has 30K on it, but the noise that has developed is coming from underneath and behind the crankshaft pulley. my first thought was a main bearing, but there is no good reason for that, and the last time I experienced that, the noise was much different. Anyway, this noise sounds like the noise a loose timing chain would make on a truck. I understand this model engine uses a belt. The noise starts after the engine warms up a bit and the idle drops back to normal. it is difficult to hear at highway speeds, but idling at a stop you can very well hear it outside the vehicle. I hope someone can point me in the right direction soon, as this noise becomes more prevalent every day. Incidentally, there does not seem to be any lack of performance, but there is some vibration, nothing severe though. Thank you.
