My passenger side y-manifold union keeps becoming loose. In the past two weeks I have to tighten the nuts because it is leaking exhaust. Short of putting red loctitite on it (dont want to do) has anyone had this issue before, an what did you do?

 

The original nuts were crimp nuts, you can replace them with that. Red high temp silicone also does pretty good at securing nuts, the silicone fills the thread gaps well and eliminates vibration loosening.

 

You can also double nut the studs which should help them from loosening. Be careful with silicone, it's great as described above but don't use it to seal the joint. Although unlikely in this scenario, it can damage catalytic converters if enough of it gets in the exhaust stream.

 

A lot of the risk of damage to cats can be avoided if you wait 24-48 hours for silicone to fully cure and shed any harmful outputs.