. “if the timing belt broke, it bent valves”
NoT true. For the 5S-FE 4cyl. to bend a valve because of a timing belt break is extremely rare, I personally have never seen it. And have replaced the broken belts on many, and had my own go due to failed water pump. The V-6 on the other hand will almost always damage a valve or three.
@PvtPublic
Which Toyota V6 are you talking about . . . ?
3.0 1MZ-FE
3.3 3MZ-FE
From what I heard, the 1MZ-FE is non-interference, while the 3MZ_FE is interference
im sorry i should have been more specific, if the timing belt breaks it doesnt bend valves on every car. sometimes not even on interference engines,
examples that i have encountered are the nissan 3.0 engine in two hands on broken belt occasions. i also seem to remember reading something about this being because ford used this engine in the quest and wanted to make sure it wouldn’t bend valves, although if you look that v6 up it comes up as interference. Also had one lucky honda 3.0 that didnt bend valves.
@PvtPublic and you are correct about the ford 4 cylinder, i believe i read at one time the only ford four cylinder engine in that era that bends valves was the dohc engine. if you look up the sohc engine i think it says it will not bend valves, and ive personally done a few. i hate to admit ive installed the belt wrong once or twice on a broken one because of the marks being so confusing.
what i meant was, if that toyota broke a belt it bent valves, 4 cylinder or six cylinder, ive seen it too many times, though im sounding like a know it all now. ha
Edit. just to cover myself here, i cant be sure on the specs of these toyota engines as i havent looked them up recently. I am purely basing this off of experience with seeing belts broken on the v6 and 4 cylinder toyota. . and installing belts, and watching them not run.
With that being said, more times than not when a broken belt comes into my shop i would rather throw a belt on it than do a leak down test, because cars will come up low on a leak down test and still run perfectly fine. it just depends if you consider low 40% or 0% . if it wont hold any pressure at all then you know something is wrong. if it holds a little pressure, put a belt on it and see what happens. thats my opinion.
40% leak down is quite bad, assuming the leakdown test was performed correctly
Even if the engine starts and seems to run just fine, it’s definitely well worn
It seems I may have spoken too soon. there are differing reports about the 1MZ with VVTi and that the 3MZ is non-interference, I sit humbly corrected ( hanging head in shame)