2004 Broken or jumped timing? help!

Hello,
Long time listener, first time caller here.
I have a 2004 Sequoia, 245K miles, timing belt replaced 20K miles ago, no rust, love the truck! This past Friday I was driving down the highway, roughly 70mph, i stepped on the gas to pass a vehicle and heard a big clunk, followed by loss of power and misfiring/running really rough(flashing cel). I l slowly drove it to the nearest mechanic, roughly 1 mile. We ran the codes, p303, p300 were firing, swapped out the plug and coil but no dice. Mechanic calls me today thinking that it may have jumped time and that the belt tensioner was ripped clean off! He has not torn into the engine yet but called me to see if he should proceed with a $1500 timing belt job, knowing it may have bent valves and the engine being shot.

Couple questions:
1. is there a way to know that the valves are bent without doing the timing belt replacement?
2. Would the belt tensioner be visible to know it was torn clean off? Wouldn't he need to take the front shield of to see the tensioner?
3. I've read others replacing their belts after breakage and not have any engine damage?
4. What would you do??

Thanks for any help or advice in advance.

 

I think most of the survivors were early pre-VVT motors. You might try pulling the spark plugs and using a bore scope camera to inspect for carnage. Tensioner actuator is front passenger side visible from underneath but the tensioner wheel is under the cover. Broken belt in 20K is very unusual - may want to question work of whoever did the last TB install.

 

I've got the mechanic attempting to do a borescope, probably by tomorrow at the earliest. Question: How would I know if my 2004 2uz-fe is part of the "pre-vvt"?

 

It is, VVT on the 1stGen Sequoia ran from '05-'07.
The giveaway for the early motor is the aluminum intake

 

Would that mean it’s not an interference engine??

 

Mechanic called back with the borescope results. Apparently he could see "marks" on 2 of the pistons which indicates damage to the valves. Is it safe to assume since the marks are visible that the engine is toast? Should I get a second opinion?

 

Unfortunately it sounds like you have your diagnosis. Sorry to hear that man. I just posted (not mine) a 2UZ from a 2003 on the BST thread. Comes with trans and transfer case.

 

Unless you trust this guy very highly I'd get it and for just the price of a borescope from Amazon (pretty cheap) and a tow you could see for yourself. Or if you really want, take it to a Toyota specialist and see what they say.

 

I have no reason not to trust him, he seems honest and is trying to help. He's going to send me some photos from the scope, hang tight.
Since the truck is a 2004 could it be possible its a non interference motor? This guy mentions it at the beginning of this video....

https://www.youtube.com/watch?app=desktop&v=SzO8X5SJDsE

 

We have been considering it a light interference engine. If the belt breaks at idle you might be OK but since it seems you were at a decent RPM it's definitely possible that you had some damage occur.

 

ok good to know, also the belt is still in tact, apparently the tensioner broke clean off which caused it to skip time.
Hoping to get photos soon so I can post here and get yours/others opinions. He is also planning on doing a leak down test if we think the damage is inconclusive.

 

Right, I guess it mostly depends on how many teeth were jumped when the timing skipped.

You're also not getting a lot of input here since this is the less active Sequoia section. I wouldn't consider myself an expert, most of it is just what I've learned on here.

 

quick update from the mechanic, he's having difficulty getting the cams in the right alignmnet for the leak down test. Waiting to hear more from him today. In the event the results are good, i am looking for a recommended TB kit. I think the after market junk could be the reason the tensioner ripped off to begin with. I've notice folks use the AISIN kit?

$183 AISIN TKT-021 Engine Timing Belt Kit with Water Pump - Compatible with Select Lexus GS400, GS430, GX470, LS400, LS430, LX470, SC400, SC430 Toyota 4Runner, Land Cruiser, Sequoia, Tundra

https://www.amazon.com/Aisin-TKT-02...1b&asc_source=01G906CFVNZ35AJ2JPV0Z6Y0B2&th=1

 

So the mechanic called....he has good compression on all cylinders, he installed a new tensioner, re-aligned the belt ( i think) and its now purring like a kitten! He was shocked and could not believe what he was seeing. He's hoping to have it back together and back to me by tomorrow. More proof the 2UZ-FE is AMAZING!!

 

That’s awesome news!