Video: strange noise at V6 engine start - chain?

[banzaj]

https://www.youtube.com/watch?v=eQ0LyHhtSFk

Hey guys, I've uploaded a very short video on youtube of how my engine starts (don't know how to embed it here, could only copy and paste the link). What's that strange noise? It appears every time the rig has been parked 4 or more hours and definetely every morning. If parked less than that, no sound. Seems to be the chain, right?

No check engine light, no errors - checked with dealer scanner. Low oil level indicator on the dashboard disappears immediately after start so there are no symptoms of low oil pressure. My mileage is 110K. I use OEM oil filters and AmsOil 5w30 or Motul 5w30.

My initial guess was that the chain tensioner (which is activated by oil pressure) is late in providing tension due to abnormally low initial pressure. But then I noticed it started happening sometimes if I press gas real hard and rev up the engine while going uphill - i.e. when I really load on it. The noise also appears for a second, not more.

Anyway, I removed the oil pan and cleaned the oil pump inlet grid and also replaced the tensioner: to no result. The old tensioner is pretty good and its rod is only a third way out of its body - it proves that the chain is not worn / streched too much.

Here's what several mechanics guess: 1) could be insufficient oil pressure - try higher viscocity oil (say 5w40) or different brand; 2) could be oil filter fault - bypass doesn't work properly or something - try another brand; 3) instead of the chain noise it could be the alternator belt rollers or tensioner's noise - replace them (I am of course still running original ones); 4) over time the chain tensioner will move out one increment more and will tense the chain up to the required level and the problem will be gone.

What are your thoughts?

 

[Greydog]

It sounds like the valve lifters are tapping just a bit until oil pressure goes up once the engine is running.

 

[drewm]

It sounds like the valve lifters are tapping just a bit until oil pressure goes up once the engine is running.

I agree. I don't think it's the chain either.

 

[KidVermicious]

x3, not a timing chain sound.

 

[banzaj]

Thanks! So what shall I do to get rid of this clatter?

 

[drewm]

Thanks! So what shall I do to get rid of this clatter?

There's no oil on the valvetrain on start until the squirters start up, this may be normal. You may want to see if other trucks do that too, my guess is they do and nobody noticed.

 

[2014 Warthog]

I don't know if this is true any more, but way back when (with my 86 toy truck) this was caused from not using a Toyota oil filter which had a backwards check valve in it so when the engine sat, the oil didn't all flow back into the pan. The filter and downstream would hold a lot of oil in place so that the lifters would get oil as fast as possible when restarting.

Regular filters didn't have this and so required the pump to completely refill the system all the way up to the top of the heads before the lifters got oil again.

At least that's what I understood at the time...

 

[banzaj]

Just an update: it was all due to the VVT-i clutch on the driver's side - it might've been stuck a bit and therefore acting slower than normal or not turning to the full range. Resolved by just working it out via Techstream - just by turning it to the full range, there's a special test for this in the software.

 

[miller507]

Just an update: it was all due to the VVT-i clutch on the driver's side - it might've been stuck a bit and therefore acting slower than normal or not turning to the full range. Resolved by just working it out via Techstream - just by turning it to the full range, there's a special test for this in the software.

Glad everything worked out.

I have the same issue, where exactly is the option for this test?

I think i'm gonna buy a techstream off ebay... any suggestions on what i should be looking for?

 

[banzaj]

I think i'm gonna buy a techstream off ebay... any suggestions on what i should be looking for?

You'd be looking for MVCI Toyota (or mini VCI)
toyota mvci | eBay

I've got one like this: V10 0 028 Mini VCI Diagnostic Tool Cable Scanner for Lexus Toyota Tis Techstream | eBay

In the Techstream you'll find the engine section, there you chose Active Test, then go for VVT-i tests, there are four of them: Linear Bank 1, Linear Bank 2 and the two others (can't remember their names) are also for Bank 1 and Bank 2 respectively. Read the description, out of those four you'll need the two ones where you change the VVT-i position manually. You can only do it with the engine idling, don't press on gas. There's a horizontal moving bar in the manual test, representing the range of VVT-i clutch turning, from minus 127% to plus 128%. Initially it's sitting at zero in the middle of the bar. If you slide it with your mouse in any direction the VVT-i will change it's position accordingly. If you slide it to the left (negative range) 0 to -127%, you won't feel any changes in the engine running. Now if you slide it to the right, after +30% and more the engine will start slightly shaking/ idling roughly (same feeling as if you had one cylinder stopped working). My passenger's side bank VVT-i was ok: while testing it, the engine instantly stopped shaking and getting back to normal once I put the slider from the positive range back to zero. As for the driver's side bank - after I moved the slider to +30% and further, moving it back to zero led to nothing - the engine continued idling roughly. It could only get back to normal if I first moved it to -15%. I had been moving the slider throughout the whole range (-127% to +128%) for about 15 minutes and then it started slowly changing to better. To stop the engine shaking, I now had to reverse the slider to -10%, then to -9%, etc. The best I achieved was -3%, almost perfect. You'll understand what I'm saying once you're there in the Techstream.

I should also note, that before I got this thing resolved I checked and replaced the main chain tensioner (which wasn't necessary because the old one was perfect), removed and cleaned the oil pan and oil pump inlet - it was kinda dirty, replaced all v-belt rolling bearings with the tensioner (all four of them), removed and cleaned the VVT-i filter nets (whatever you call them correctly - anyway, they were clean though) switched to TRD oil filter instead of Toyota 90915-YZDD3, switched to AmsOil SS 5w30 synthetic oil. I can't say if all of this helped in combination, but I've calmed myself by thinking that it was worth doing as a preventive maintenance.