Old Hoses for Lexus older than 2000 LS400,etc (1998)

[Zeus253]

I found that it is a very good idea to change hose clamps from OEM to new type (flat head/hex bolt), wrapping with High Temperature Electrical tape, not to tighten with power especially at the end of tightening. Helps with life of the seal at inlets. For all other rubber hoses not replaced, recommend using (an approved for rubber) silicone lubricant to gently condition the hoses. Same stuff can be used to condition window/rubber track and door seals. Refer to use details on can. Last, even the smallest of air/vacuum leak will cause numerous issues including engine functioning, engine life, check engine lights, vsc off code, and more.

[paulo57509]

Worm gear clamps should be tightened to 15 in-lb per this reference:

https://www.amazon.com/Fasteners-Plumbing-Handbook-Motorbooks-Workshop/dp/0879384069/ref=sr_1_2?crid=3URGE7KS5052A&keywords=automotive+fasteners+and+plumbing&qid=1677445807&s=books&sprefix=automotive+fasteners+and+plumbing%2Cstripbooks%2C156&sr=1-2

Worm gear clamps do require periodic re-torquing.

[RX400h]

Rubber hoses lose their plasticizers over time. As they do, the rubber cannot act as a compression spring of sorts, causing leaks from insufficient conformity to the neck, or from cracking/splitting of the hose.