I have a 1JZ swapped Mazda Rx8. This is my first JZ engine, and just got it running, so I'm kinda green when it comes to them so bear with me. I have noticed that when the car sits for say 12+ hrs or more that I have a very light top end rattle for maybe 1-2 seconds, and only when the engine has sat for the listed time period. After that it runs quite as a church mouse all day and never makes another sound. The next time I started it after sitting I watched my OP gauge, and the light rattle stopped as soon as it had oil pressure, which is why I believe the oil is draining back into the pan as it doesn't do it any other time other than after sitting a long time. It doesn't sound like a bottom end issue to me as the sound is just way to light. Here is what I have : Drift Motion Thermostatic Oil Cooler Adapter Front Mounted Oil Cooler Wix 51348 Oil Filter Rotella T6 5w40 Full Synthetic I have read many threads on this, and maybe I'm just worried over nothing, but its one of those things that once you hear, you cant un-hear it. Any help would be greatly appreciated.
If it’s any consolation my car (1JZ gz20 soarer) is the exact same both before and after fitting an oil cooler and filter relocation. Was worse with 10w60 oil and I I have dropped to 5w50 simply because of the top end noise on start up.
Dang..Well when I got up today, I went out into the garage and set up my camera to take a video of it, and Ill be damned if my car didn't make a liar out of me. It sat from mid night last night till 1pm this after noon and didn't make a sound.
