oddity... 2uz fe... prior to timing belt breaking, there was smoke (1 Viewer)

[angerhater]

so the timing belt in my sequoia broke a couple of weeks ago, while tearing it down I find that the driver side timing belt cover is slightly burned on the surface that seals , near the outside closest to the battery/ above the ac compressor. why?

 

[GLTHFJ60]

Can you tell what it's burned from? Did the belt fly and wear through a bit, or was some misplaced hose rubbing on it?

Without eyes on it or pictures, it's gonna be hard to say.

Also, did the motor survive when the belt broke? I assume it's a uz interference motor, but I don't know sequoias at all.

 

[angerhater]

fingers crossed on bent valves. I tried to peek with a borescope and did not see any impacts, but hard to tell where to look on the piston face. I need to get some pics tomorrow of the burn area. there does not appear to be any marring from the belt. more like a small hole where the cover seals against the head . oddly the truck threw a check engine light, miles before the belt broke.

 

[angerhater]

kinda overwhelmed with so many things going on, that I haven't been able to keep my head focused on the truck. I have parts coming in and feel like I am missing some odd gremlin. likely bad valves.....

 

[lt1fire]

2uz is an interference engine. At the very least I'd say a bent valve or two. As for the burn as Johnny said it's pretty hard to diagnose without seeing it.

EDIT: it appears only the later vvti motors are interference.

 

[roadstr6]

I think what happens lots of times is that the tensioner breaks first and then the belt gets sloppy and either jumps time, or flops around until it wears against something else until it snaps. This might explain the CEL and smoke a few miles prior to the belt letting go. I have read here on MUD that the non VVT engines are not interference. Many folks with broken belts on the older engines with no collateral damage. Were they just lucky? I don't know for sure because I've never been into one. I do know that the timing belt, WP and tensioners should all be done at the same time as part of the timing belt job. A bad tensioner can cause a lot of mayhem.

 

[uzj100]

My daughters 99 timing belt broke on start up and we replaced the belt and it was fine. There is so much info on the web. My understanding is the 98 to 05 non vvti are non interference. 06 and 07 are interference. However i can not find a definitive answer on either.

There were weird burn marks inside the engine from the belt tearing apart. Nothing on the outside.

Good luck.

 

[Comet]

My ‘99 is non interference. My wife’s ’03 GX is the same. It is the VVTI that can cause issues. @angerhater I would guess that you are in luck with the year ‘03 as long as it isn’t plastered with VVTi all over the engine covers. Engine covers, why?

 

[angerhater]

Here is the burn spot

 

[angerhater]

And this is the face where it connects

 

[angerhater]

Maybe timing jumped and caused it to run hotter? Although the temp gauge was normal. I don’t want to put it all back together if something here needs attention. Now the engine had been running for about two hours straight when this happened . The truck seemed to be running fine no loss of power or skipping that I noticed.

 

[GLTHFJ60]

I wouldn't worry about the cover spot you pictured man. Get the motor back in time with a new belt and tensioner, then slap everything else back together.

 

[angerhater]

And water pump is the plan. Wish me luck

 

[angerhater]

got it all back together, fired right up. but has a decent knock or clatter, yet revs smoothly in neutrral.

 

[angerhater]

I think it hates me. the belt jumped a tooth on both cams, So I had to redo a bunch and it still knocks, not sure if it jumped a tooth again or its just hurt. butit does run

 

[angerhater]

i think it jumped again, 2 teeth.. I think I need a bigger hammer... for my forehead...Doh

 

[Hokie LX]

If you put a new tensioner on and lined up the belt correctly it shouldn’t have jumped again. Are you putting all the slack on the tensioner side of the belt? It should be taught on the other 2 sides.

 

[Comet]

I was thinking tensioner too.

 

[lumbee1]

I bought the AISIN 2uz timing belt kit from Amazon. Kit includes Water Pump, Timing Belt, Tensioner, Pulleys, Gasket, Seals, and Installation Instructions
www.amazon.com/gp/product/B008EEYWKI/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[izzyandsue]

Look at 24:30 on this video, could be something like this?