docdgt@com

Question: I have a 97 400LS with 90k miles, which, according to the schedule requires a timing belt change. Has anyone had experience with allowing their car to go longer than this mileage with the original belt? Can it be examined visually to see if it is in good condition or not? Would it make any sense to have the belt examined by someone who is familiar with this timing belt, and if this person stated it was in good condition to continue this practice for another 5000k miles or until such time this experienced person states that it is time to change it?

Any help or suggestions will be greatly appreciated.

PureDrifter

iTrader: (10)

please search

https://www.clublexus.com/forums/sho...92&postcount=7

mitsuguy

iTrader: (2)

no way to tell for sure how long... they are typically over engineered, but it's not something you want to break... follow the guide...

not sure if the LS400 in 97 went to interference or not off top of my head, but if it is an interference engine, if it breaks you are buying yourself a new motor... if it's not an interference engine, if it breaks, you just replace it as well...

CptnTonus

According to PureDrifter's post above, the 2LS 1UZ is an interference engine, so that's not something I'd wanna mess around with. Change your belt, and while you're in there it's a good idea to replace all the other timing components like the tensioner/idler pullies and the water pump as well.

PureDrifter

iTrader: (10)

89-94 LS uses 1uz that is NOT interference.
95-00 LS uses 1uz that IS interference.

Harky

The 4.0L engines in the 1989 thru 1997 LS and SC models are NON-INTERFERENCE designs. This can be verified at the Gates site noted in this thread as well as several other authoritative web-sites like lextreme.com.

This makes the decision whether to run your TB beyond the 90K recommended change point rather important. The difference being a broken belt with NO engine damage, or a broken belt and a broken engine!!

You are OK with your 97.

PureDrifter

iTrader: (10)

please link to the exact info u have since in my 5+ years of owning an LS i havent seen such info.

well known member and resource JBrady backs up my original statement in this Lextreme post.
http://www.lextreme.com/forums/showp...09&postcount=5

mitsuguy

iTrader: (2)

welll.... I had to do some research....

here's a table of non-interference lexus motors:

PureDrifter

iTrader: (10)

which 3rd party manufactuer made that list? it doesnt make any sense since Lexus reccod the TB be changed every 90k mi. AND Lexus didnt change the motor between 96 and 97

mitsuguy

iTrader: (2)

Mitchell... only the biggest 3rd party technicians guide in the world...

PureDrifter

iTrader: (10)

Dayco, one of the largest Timing Belt/chain and asst. engine accessory manufacturers in the world.

sonyman

All the information I have gathered has pointed to the 1995-1997 engine being an interference motor, regardless of the information presented by 3rd parties.

mobilyte

iTrader: (3)

my understanding was that the vvt-i motors were interference types and the LS didnt have vvt-i until 98.

maybe the factory service manual has the definitive answer, the engine mechanical section in my manual states:

"Pistons are made of ... , and a depression is built into the piston head to prevent interference with the valves."

PureDrifter

iTrader: (10)

that is true except the fact that the 1UZ was changed (head design mainly) for the 95-97 cars. this is why the 95 is rated ~10hp higher than the 89-94 cars.