Replaced Timing Belt, Engine Seizing

I went and replaced the timing belt and some other things like the water pump at 95k miles after my dad put water in the coolant, but now the engine is seizing (it would start before I changed belts).

While taking off the old belt, one of the cams somehow shifted a little bit, and I had to crank it around again to line it back up. I got worried it was 180 degrees out so I think I did an extra revolution after that. I put the new belt on and lined it up fine. I'm not even sure that's a thing with this engine though. Maybe I put the belt facing wrong? The pics are how the belt was after I opened it all up again, I didn't crank it at all since then.

 

More than anything you need to verify the timing before you drive another mile. I highly recommend reading this page: https://www.toyoheadquarters.com/threads/toyota-2uz-fe-timing-belt-marks-4-7l.335/

But … If you’re not going to give us a lick of info about your truck, (year, cab, drivetrain) how the hell are we supposed to help you?

Also, you didn't touch the cam seals in that "other stuff" you did but aren't listing out, did you? There's a mistake others have made that will cause big ass headaches if so.

 

If the cam jumped - you didn’t place it in the correct position before removing the belt. It was crucial to have the timing aligned before putting the new belt on.

what does water in the cooling system have to do with any of what’s going on?

 

Hopefully your engine is OK, but not enough info to help.

 

The timing was lined up fine. Its a 2006 4.7l double cab. All I did was rotate bank 1 cam by hand back around to realign it. I replaced a tensioner, serpentine belt, battery, oil, while I was in.

It was lined up to the "T" before I took it off and it still had slipped. The water pump had been corroded and some pink caulk stuff had formed around a belt wheel.

 

If you rolled the cam full revolutions without moving the crank there is an extremely high likely hood that valves contacted pistons.

I’m not clear on whether or not you tired to run the engine following the belt change…

what brand belt did you use?

 

I'm focusing on this. When the cam jumps it is only a few degrees, say from 12 to2 position or 12 to 10. There is no need to " crank it around again".

 

Also one revolution of the crank is two revolutions of the cam

 

For clarity, isn't it the other way around? The crank gear is smaller than the cam gears, requiring two revolutions of the crank (suck, compress, expand, blow) to turn the cams one full revolution.

 

Correct - 14:25

https://youtu.be/fM1A0DWhRHc?t=864

 

I ran the engine and it wasn't turning over. I used an ADELCO TB298 timing belt.

 

Yikes. Did it feel crunchy and with varying resistance when rolling the cam?

 

I think people here want to try and help you, but you need to post with a little more detail and try to use correct terminology. Diagnosing engine problems through the internet is hard enough. Nine word answers makes it impossible. If English is your second language have a friend post your comments.

An engine can not be both running and "not turning over"

 

Yes, I typed it bassakwards

 

Only at night .....or is only in the southern hemisphere?

 

OK IF THE TIMING MARKS LINE UP THEN THE CAMS ARE IN POSITION AND I DONT HAVE TO WORRY ABOUT 180 DEGREES OUT?
The old belt never snapped and the pistons/valves should have been fine. Rotating the cam around back into place as gentle as it would go was enough damage to stop the engine from turning over?

 

I'm not familiar enough with DOHC setups to answer the first part - but as for rolling the cam - you’re forcing metal valves into the top of the piston(s) that are up… something is going to bend or break if they aren’t working in conjunction on an interference engine.

 

what are the easiest diagnostics to check

 

Borescope in the spark plug hole would tell you a lot. Like whether the crank is TDC or 180 and if anything got mangled on the bank you spun the cam. If that all looked normal I’d try rolling it over by hand.

 

My mechanic just doing mine. Doesn't look to bad just a slight crack but I doesn't have record before so mental health first I already have 3 years with the truck

 

My pump was completely corroded, had to replace it as well as the thermos and thoroughly clean off the mating surface. Still need to add coolant and rinse it all out once its back together.
Also I mistakenly said the engine was seized in the topic title when I meant to say that it wasn't turning over.

 

When you say it wasn't turning over, can you explain that a bit more? Did you hit the starter once the engine was assembled and it didn't spin at all, or spun a little and is now stuck and the starter doesn't spin it? Or does the engine spin with the starter but doesn't fire up?

 

The engine spins with the starter but didn't fire up.

 

Will it start with starter fluid/ether?

There are a number of things at the front of the engine that will cause no-start. Coolant temp sensor is required to allow start, the crank position sensor is required to keep fuel pump running, etc. More details needed.

Did you already verify timing is 100% correct across multiple revolutions?

 

Hold up. We went from seized to not turning over to not starting... three VERY different scenarios.

It sounds like the truck has been put back together and is simply not starting.

First thing to do. Verify your timing! With the crank set to TDC (0 degrees), do the cam gear alignment marks line up with the alignment mark on the head?
Please note:

• The front of your cam gear looks different than mine, but the alignment marks are still there.
• Since you turned the motor over trying to start it the alignment marks on the timing belt wont be lined up, this is normal.

 

oh yeah thats cause I didnt know the difference. I cranked it, got the sound, didn't start.
The timing marks in the original pics were how it was when I opened it back up, and I believe thats how I left it (I thought that this meant there was no movement in the parts when I cranked it, and I thought that's what not turning over meant). I rotated it to 0 just now, and it lines up like yours with the R-cam mark just a tiny bit past the line, but lines up with the L-cam perfect. There was a little confusion with the belt having a line in an awkward spot between the tooth and the groove, as well as no markings for which cam the line should be placed on, but I don't think enough uncertainty to take it out and put a different one in. I showed it to another auto forum and they agreed the alignment is probably as good it gets with this belt. I don't know if its possible that certain lines were supposed to go on certain cams when placing it on.

I had to charge the battery to get electrical, I'll probably replace it entirely next time but I don't think it was too weak.
The tank may have been empty. I added a gallon of fuel to it, but it is parked on an incline so I don't know if that will cause issues and I should add more.
I replaced the spark plugs before the timing belt. I went and checked on them afterwards, and didn't see anything off.
My mechanic neighbor thought that I had one of the cams 180 degrees out after the mishap, so I pieced it out again, but I thought that if all of the timing marks line up after spinning it around once, that's an impossibility with this engine?

 

The Toyota belt has marks to ensure you aren’t a tooth off anywhere when you pull the pin on the tensioner - wouldn’t be surprised if the AC Delco belt didn’t have that feature. Even if you were a tooth off, I’d expect it to fire so I’d be looking at cam position and crank sensors. Try the starter fluid in the intake as suggested to see if it’s a fuel delivery problem.

 

The 2UZ doesn't care if you happened to rotate a cam 180 out or not. As long as all of the timing marks line up at TDC you are good to go. Based on your description of the timing alignment marks, it sounds like you have it timed correctly. Using a quality timing belt (OEM or Aisin) would have probably made the belt installation far less confusing. While you have the truck torn apart, you may want to do some reading on the forum/online about the extreme importance of using ONLY a Toyota or Aisin supplied timing belt kit.

For what it's worth the 2UZ will run with the crank out of time with the cams by a tooth or two, albeit not well. When I bought my truck it had misfires on all 8 cylinders and couldn't maintain 60mph up a hill. The crank was 15 degrees ahead of the cams It ran like crap.


I speculate the cam position sensor is either not plugged in or the wiring has been damaged. A damaged or unplugged cam position sensor will prevent the motor from starting. The cam sensor is on the drivers side, between the cam gear and water pump. Make sure the wiring gets routed behind the coolant pipe and not in front of it. See this thread for issues it can cause: https://www.tundras.com/threads/p0340-code-camshaft-position-sensor.95343/

Double check all of the electrical connections. If it fires with starter fluid sprayed in to the TB, put 5 gallons of gas in it and see what happens.