GS400 430 Timing belt question

[BillH2]

Looking at a number of GS400's and 430's with 45 to 85K. I have been told that Lexus service calls for a timing belt replacement at 90K. Do these engines bend valves if the belt breaks? Anyone know if belt replacement HAS to be done by a Lexus dealer. (140 miles away from here)
Looking for a red 2000 2001 GS400 430. Nav would be nice, but not necessary.
Thanks
Bill in Washington State

 

[Zuffen]

If the belt breaks no harm will come to the valves. But why wait for it to happen when you can change it at a time that suits you?

You can do the belt change yourself. Whilst changing the belt it is a good idea to to change the tensioner idler and the waterpump as they are both exposed when you have the front cover off the engine. In reality it would be a good idea to the whole hog and replace dizzy caps, rotors and probably leads.

There's a write up on a belt change on www.planetsoarer.com Website.

 

[BillH2]

If the belt breaks no harm will come to the valves. But why wait for it to happen when you can change it at a time that suits you?

You can do the belt change yourself. Whilst changing the belt it is a good idea to to change the tensioner idler and the waterpump as they are both exposed when you have the front cover off the engine. In reality it would be a good idea to the whole hog and replace dizzy caps, rotors and probably leads.

There's a write up on a belt change on www.planetsoarer.com Website.

Rod
Respectfully, what are dizzy caps? I assume leads are the plug wires. I most certainly would do the whole thing including the waterpump.
Thanks
Bill

Horsepower: Some is good, more is better, too much is just enough!

 

[Lextreme II]

Here is another article on timing belt change www.lextreme.com/timing.htm

 

[BillH2]

Never mind, I figured it out.

Thanks
Bill

 

[TundraEddie]

In reality it would be a good idea to the whole hog and replace dizzy caps, rotors and probably leads.

There are no caps,rotors,or wires on GS400/430 1UZ/3UZ engines,indvidual coil ignition

 

[Zuffen]

Sorry Eddie,

I'm still stuck in the "Dark Ages" of the 1UZ!

 

[JBrady]

Actually YES... you would bend valves. The orginal 1UZFE is non-interference at 10-1 compression but the 1995 going to 10.4-1 is interference and the 10.5-1 VVTi in the GS400, SC400 and LS400 from 1998 on are all interference engines.

 

[Lexuslvr]

Mine failed....at only 68000 miles

My 98 LS400 failed....I am wondering if anyone else has had one fail like this.

Car has been perfect....until now.

I hopped in, and started it up. Sounded like lifter noise (loud) so I shut it down within 5 seconds.

Tried starting it up again and it acts like the timing is advanced. My thought is that it jumped a tooth in the timing belt.

The noise...is bothersome. I am hoping I didn't bend valves.

I hope to pull the covers and take a look so I know what to expect. I hate to take it to a dealer and get "surprised".....

Any feedback is welcomed!

T

 

[Lextreme II]

I hope your Valves are ok.... I think 98 and up have interference engine. I have some tutorial on it www.lextreme.com/timing.html and www.lextreme.com/timing2.html

 

[Lexuslvr]

Update on 98 LS400

Finally got a chance to pull the RH cam cover and spin the crank. The timing marks line up and the belt is OK...Now to try starting again and see what the problem really is.

Tom

 

[Lexuslvr]

98 LS 400 cam belt problem

Although the symptoms seemed to indicate a timing belt slip/failure, careful inspection revealed no damage. Timing marks lined up, so I reassemble the little I had taken apart, held my foot to the floor and cleared the engine out until it started.....runs just like it had before....perfect.

NOT a cam belt problem...my misdiagnosis.

Will change it at 90k.

Tom

 

[pinoiryder]

on the 90 ls400, will the cam get bended if the timing belt get broken? my belt got shreded today,

 

[qca]

should be fine

 

[Lextreme II]

Pino,

My mechanic installed the wrong cam gear position and the engine was cranked many times but it didnt hurt the valves. I have a 1990 LS400. However i dont have low compression pistons.

 

[pinoiryder]

Lex,
just finish installing my new tming belt, thank you for the information on how to replace the timing belt. it took me twice to remove and put t bcak together again, second time i was in luck,my car start right away, once again thank you for the information..

 

[Lextreme II]

Pino,

You are very brave.... The information i had was just for search engine. I didnt know it would work. Just kidding...lol.... good job....

 

[pinoiryder]

Crank timing seal leaking

after replacing my timing belt, i notice some oil dropping on the dround, went to check it if it is coming from my oil pan gasket, i cleaned the oil pan gasket to see if the oil is coming from there, i strarted the car and went under the engine to see if the leak is coming from the oil pan, i noticed that the leak is coming from my crank timing, in my conclusion i think it is my crank timing seal that is leaking, when my timing belt got shreaded half part of it is rolled on the crank timing and it even bended my timing belt guide crank angle sensor, my question is can this be a DIY project? has anyone done this before? do i have to bring my car to a real mechanic to get it fix?

 

[Lextreme II]

Yes you can. You will need to take out the crank pulley. Bascially, you have to redo the whole timing deal again. Normally, people change seals, water pump and some pulleys also.....

 

[JBrady]

90k miles is a conservative recommendation as you would expect from Lexus. Yes, if the belt breaks valves will contact pistons and substantial damage would occur. However, the belt is very strong and reliable. Check out my post.

http://www.lextreme.com/forums/showthread.php?t=3918

Unless you consider me a Lexus dealer (not) then the answer is any compentent mechanic can replace the belt. You can order one online for about $50. Since the labor gets you well into the engine many recommend replacing the idler and tensioner pulleys along with the water pump. Some recommend doing camshaft seals. I felt all of these items were fine on my motor and only did the belt. Of course if needed I will replace them myself and therefore I am not concerned about repeat labor costs.