Benemerson

Changed timing belt and water pump on 2008 GX470. Double and triple checked timing marks on belts on cams and crank before reinstalling. Ran for 5 seconds, made clunking noises and now crank only spins about 3/4 of a revolution. Ideas?

vwynn

iTrader: (4)

did you TDC the "T" on the cam or the "I" on the cam?

Benemerson

IanB2

That's where my head went when I read your original post. That really sucks.

Get your dealership to break out the labor portion of their quote, and source your own engine if you want to save some money. Good luck.

jimzilla

So sorry this happened to you. Nightmare material.
I am planning on tackling this job myself though and wanted to ask a few questions. What belt or kit did you use? did you use the OEM AISIN kit? Did you turn the crank twice by hand to ensure the lines still matched on the cams before you started it up? Sorry if this is rubbing salt in the wound, but i'd like to understand what went wrong to avoid the same mistake. What type of guide did you use to perform the operation? youtube or official toyota manuals? Thanks in advance.

spacekase

This is rough. Its basically everyones's fear when cranking that engine for the first time after the job.

Did the cams move at all? When the belt was off?. Using the "I" leaves the cams under tension.

EddieK05

Yes, I used the Aisin kit. Ordered this : . You'll want to add a thermostat and drive belt as the kit doesn't come with them.

I had my indy do mine and after the above story, I would never even consider doing it on my own.

FrankT

vwynn

iTrader: (4)

Yea i did mine and didnt run into any problems so long as i REALLY double checked the markings.

Check Passenger cam mark on "I" + Check belt mark line
Check Driver cam mark on "I" + Check belt mark line
Check crank mark is at 2 o clock position on the notch
Get under the car and check that the belt mark on the crank is correct as well.


This is the video i used. 25:50 is when he starts double checking the reference marks.

Good luck in your decisions. 13k for a motor is essentially a whole used GX in decent condition.

Benemerson

Thanks for all the comments. Yes, the cams did move after I took the old belt off. I lined them back up as I put the belt on. I checked the marks three times as I went through the various stages of reassembly. First, I put the belt on and lined up the marks on the cams, the crank, and the new belt line underneath the crank. Then checked the I and camshaft marks again after rotating the crank two revolutions. At this point, you can’t check the new belt line indications anymore as they’ve rotated. Then I rotated it again two revolutions and the marks lined up. Proceeded to reassemble and checked it one more time before covering up the crank. Yes, rotated the crank twice each time. Obviously, I missed something as others have had success. I followed the same video as identified above - which I found quite good.

I would really challenge yourself with some critical thinking if you’re considering doing this. I consider myself a decent mechanic but this is a complicated engine. I do remember thinking to myself before I took off the old timing belt, wow, this is mechanically complex - I’ve rebuilt several old engines but this was my first major work on a modern engine. In retrospect, I wished I’d stopped right there. In other retrospect, I believe that some other folks have marked the old belt before removing it - I only marked the cams and crank.

I did use the OEM Aisin kit which included the water pump, both pulleys and a new tensioner. I’ll also note that the original belt looked FANTASTIC when I pulled it off after 120K miles - verified with the dealer that sold it to us that there’s no record of it being changed. Seriously, there was no discernible visible wear. But I’ve read the stores of what happens if the belt breaks on these engines so decided better safe than sorry. There are so many other maintenance projects you can do yourself, I would leave this one to the pros. Again, thanks for the comments. I’ve found this forum to be very helpful in the past.

As a final update, I’ll note that we elected to go for the used engine - it’s actually refurbished and comes with a 12 month warranty. About $7K all in - the timing belt was going to cost about $2K to have done by the dealer so I’m $5K in the hole but have a somewhat “new” engine that should propel us another 8-10 years in this vehicle - which has been a terrific vehicle, my self-harm incident notwithstanding! I’ll be happy to share our experience when we get the vehicle back in a week or so. The dealer is Stevinson Lexus in Frederick, CO and they’ve been great so far.

spacekase

Man, glad you've found a solution to get back to normal with the used engine. With all things said and done I can only think of a few things that may have happened one being moot since you manually rotated.

1. The cams did move after the belt was removed. That could possibly have an effect on the valve timing, however. You manually rotated and would have surely come to a stop if the there was no clearance...sooo.

This is why I went against the grain of the majority of videos using the "I" mark instead of the "T". The "T" is purposefully there to use for the belt replacement and puts the cams in a neutral state. Everyone uses the "I" because thats what others have used. Technically you can use any position "I", "T", whatever as long as all three pieces are in sync (both sprockets and the crank). I verified this with a Toyota Master Mechanic as well as a local shop that only works on Lexus vehicles that only hires Toyota/Lexus techs with dealer experience. They all said the "T" is what they use, So thats what I used and I had zero movement on the cams through the whole process.

2. Failed tensioner.

T Mark for reference

JLee50

Used engines are all over car-part.com for ~$1500. I'd get one of those.

Edit: Oops, should have read first! I'm glad you got it sorted

jimzilla

spacekase, if you use the T marks then the crank marks won't be aligned. is that correct? Do you just need to make your own marks with a paint market then for the crank or is there a second factory marking for the T position on the crank? does it even matter?

spacekase

Same process just line the cam mark with the T. All the physical markings are there. The crank marks will be towards the bottom when using the "T" marks. This link was the best reference: ToyoHeadquarters




Just make sure to get a belt with the markings to make install more confident.
I did mark my old belt and matched up the new belt tooth for tooth and the markings all lined up just for piece of mind.

jimzilla

excellent, thank you