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1998-2000 LS400 (1UZ-FE) and
2001-2006 (3UZ-FE) engines are , save for the bore diameter, similar in many ways.
The Left bank Ventilation (PCV) hoses appear similar on both models (2004-2006 loses the grommet in favor of screw-in PCV valve) 2004-2006 LS430.PCV valve is threaded into valve cover. It would also appear the inlet side is slightly larger. Will compare and advise. 1990-2000 LS400 and 2001-2003 LS430 use a rubber grommet on valve cover with press in PCV valve.
The right bank valve cover of the 2001-2006 3UZ-FE dispensed with the small diameter ventilation tube in favor or larger diameter that appears capable of doubling airflow.
This should increase scavenging efficiency of the PCV system, while reducing noise flowing through the LS400 90 degree match-cut valve cover tube.
The rubber vent tube is also larger I.D., so matching the LS430 valve cover port to the LS400 will require modification to the mating port on the air intake resonator.
Numerous posts on the plastic tube for PCV hose breaking off, so simply a matter of using a larger barbed brass hose threaded fitting.
My original was broken, and repaired with a brass hose barb so will locate and reinstall with larger fitting.. LS430 on left, LS400 on right depicting larger vent tube. Preliminary efforts at polishing the LS400 valve cover. Close-up depicting valve cover vent tube. LS400 is match cut at 90 degrees with smaller diameter and is noisy, while the LS430 employs a solid, quieter and more efficient 45 degree transition.
Lexus parts diagram of Left and right bank vent tubes
PCV system upgrade 1998 - 2000 ls400
