Interference Engine...or Not?

[mickg]

My '94 Owner's Manual lists two maintenance schedules: A & B.

Timing belts are listed for replacement at 60,000 mile intervals, but only under Schedule A (extensive idling, low speed driving, police, taxi or door-to-door delivery use).

Interestingly, replacement is not called for AT ALL under Schedule B, which defines all other driving styles.

I have to then believe that with routine inspections, my timing belt should last at least until the water pump gives out, and then the job becomes worth the cost and effort.

If rupture of the TB resulted in catastrophic failure of the Gen I engine, surely this would be noted in the maintenance schedule.

gen1 (90~94) & gen2 (95~97) are all non-interference engine. gen3 (98+) are VVTi which is an interference type to get more horse power.

90~96 is recommended to change TB at 90K, but for 97 and up, lexus factory recommends 120K or 7-year whichever comes first.

←

[silvermate]

I have to then believe that with routine inspections, my timing belt should last at least until the water pump gives out, and then the job becomes worth the cost and effort.

If rupture of the TB resulted in catastrophic failure of the Gen I engine, surely this would be noted in the maintenance schedule.

yeah thats what throws the TB, when the water pump seizes/fails. its pretty rare for the belt to break on its own, they are extremely ridged.

the Gen 1 LS400 is a non-interference engine, its a fact.........end of discussion.

[027922]

For what it's worth...my 90 LS at 133k developed a slow coolant leak at the water pump. Along with the pump I had the timing belt replaced - it was the first time the belt was replaced.

[99lsguy]

I have to then believe that with routine inspections, my timing belt should last at least until the water pump gives out, and then the job becomes worth the cost and effort.

If rupture of the TB resulted in catastrophic failure of the Gen I engine, surely this would be noted in the maintenance schedule.

yeah thats what throws the TB, when the water pump seizes/fails. its pretty rare for the belt to break on its own, they are extremely ridged.

the Gen 1 LS400 is a non-interference engine, its a fact.........end of discussion.

←

Agree again and again

A buddy of mine has a 97 Coach edition w/ 120k+ and has no trouble with TB. If I don't hear any "growling" from the WP I'm not going to change it out either ---should get 120K+ w/ no problem

Just keep an occasional eye on her for any leaks & ears open...........

[JPI]

Guys and Gals,

Let's clear something up shall we? Just remember one thing. Anything with VVT-I is interference engine.

JPI

[99lsguy]

Guys and Gals,

  Let's clear something up shall we? Just remember one thing. Anything with VVT-I is interference engine. 

            JPI

←

Absolutely