Real simple DIY today. If you're on the hunt for vacuum leaks, one that often gets overlooked is the o-ring that sits between the rocker cover and the oil filler spout.

Replacing this is dead simple. Just remove the oil filler spout with some kind of pliers. Make sure you're orienting them the right direction or the teeth will skip over the oily surface.

Once removed give the area a clean. Remove the old o-ring and replace. My OG o-ring was the consistency of super hard plastic and even cracked when I removed it. The new one is super supple rubber, as one would expect.

Installation is just reverse of removal. I just snugged it up, don't over tighten.

Part number for the new o-ring is 564258.

 

Oh this may be the fix I've been looking for.

Mine was super hard, not cracked but cracked when removing it.

I found an O-ring assortment from Lowe's.

#107 (1-7/8" x 1x1/2" x 3/16) is a very close fit.

Now I just need to sit at some long red lights and see if this is the fix

 

FWIW the OEM LR o-ring was only a few bucks if it means a better fit or material.

 

Interesting... then not fully tightening the oil pouring cap causes vacuum leaks, with the error codes that such may trigger ? What is expected with engine idling without the oil pouring cap; some suction or some pressure or none ?