Is it my turbo?

[fridayman Senior Member Find all posts View Profile Close fridayman]

Today my Prado started making a new noise under load. It is making a very brief whinning noise just as the boost gauge needle passes 12psi (I have a manual boost controller). Once the needle has passed 12psi I can't replicate the noise by trying to keep the boost gauge at 12psi, or making move up and down over 12psi. To replicate the noise I need to back off completely, then accelerate past 12psi again and the noise will return very briefly. Could it be the turbo? It sounds like the noise might be turbo rpm related, and only happens when the turbo is accelerating past a certain rpm but I can't know for sure. Anyone have any ideas? Does the turbo need to come off to check it, and what do I need to watch out for if I pull the turbo off?

[OziOffroad Senior Member Find all posts View Profile Close OziOffroad]

Have you checked for boost leaks? (hoses, fittings and intercooler end tank etc etc)

With a little pain (Read - Skinned knuckles) you can get the turbo intake elbow off while the turbo is still installed. It's fiddly but here's enough room to check shaft end-play with a dial indicator gauge. You can also visually check the vanes at the same time. That's about all there is to checking it.

The stainless compression gasket on the elbow can be reused.

Expect some oil in there from the crank case breather which enters at the elbow.

Doing it this way saves removing the whole unit, draining coolant, buying gaskets.

Mick

[fridayman Senior Member Find all posts View Profile Close fridayman]

I haven't checked for any leaks yet, but will do tomorrow. Although if it was a leak I wouldn't expect the noise to stop so suddenly while the boost was still increasing... Thanks for the info, that has saved me a heap of time tomorrow. Hopefully I can buy a dial indicator somewhere tomorrow morning.

[fridayman Senior Member Find all posts View Profile Close fridayman]

I forgot to ask... What would be acceptable runout if I can get hold of a gauge tomorrow?

[OziOffroad Senior Member Find all posts View Profile Close OziOffroad]

Don't thank me yet it's a fiddly friggin job with bugger all room for your hands, on the up side at least you vehicle isn't off the road for a whole day.

Set up the dial indicator (either use the magnetic stand or take that off and use vise grips to clamp the arm onto something rigid - depends on what stand you have and what the arm configurations is) and move the shaft with a long pair of needle nose pliers by the nut that holds the impeller on. The really long pliers with a bend in them are useful for this if you have a pair.

Just be very careful not to slip and damage the vanes of the impeller.

Not sure what the specs are off the top of my head but can get them for you if you don't have access to a workshop manual.

Mick

[OziOffroad Senior Member Find all posts View Profile Close OziOffroad]

I forgot to ask... What would be acceptable runout if I can get hold of a gauge tomorrow?

PM me your email. I'll send you what you need.

Mick

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

Fridayman what part of Brisbane? I have dial indicators you can borrow but not really sure what runout will tell you. There will be some lash in the bearings but how much I don't know. Bearing noise will usually get worse with increasing rpm. Change your boost controller lower and higher and see if you get the same issue. I can't really offer anything.

[OziOffroad Senior Member Find all posts View Profile Close OziOffroad]

Fridayman what part of Brisbane? I have dial indicators you can borrow but not really sure what runout will tell you. There will be some lash in the bearings but how much I don't know. Bearing noise will usually get worse with increasing rpm. Change your boost controller lower and higher and see if you get the same issue. I can't really offer anything.

Yeah I got my doubts too, such a small plain bearing would never make enough noise to hear over the engine. Only thing could be a bit of impeller harmonic noise at certain shaft speeds if its flopping around too much.
I'd be looking for other (easier) things first.

Mick

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

I thought the 1kz turbo was a pretty robust unit. Might just have achieved a build up of yuck that causes a whistle at that flow. Pull the intercooler and have a look, might be a bit manky in there!

[OziOffroad Senior Member Find all posts View Profile Close OziOffroad]

If you have a shuttle valve style boost controller maybe give it a clean and make sure the check valve is free and not worn. They have a tiny hole in the body of them which might need cleaning too.

End thrust on the turbo should be 0.15mm or under.

Radial play should be 0.11mm or under (you measure this through the oil feed hole)

Mick

[OziOffroad Senior Member Find all posts View Profile Close OziOffroad]

I thought the 1kz turbo was a pretty robust unit

Very! almost bullet proof.

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

Anyway fm offer stands, you'll have to come over to get them though as I will be up to my navel in Colorado, cleaning a dirty dirty dirty white thing and mowing. Unless the heir to the throne can be convinced to jump on the tractor.

[fridayman Senior Member Find all posts View Profile Close fridayman]

Fridayman what part of Brisbane? I have dial indicators you can borrow but not really sure what runout will tell you. There will be some lash in the bearings but how much I don't know. Bearing noise will usually get worse with increasing rpm. Change your boost controller lower and higher and see if you get the same issue. I can't really offer anything.

Awesome, thank you. I'm in Pullenvale. I'll have a poke around first thing tomorrow and if I can't find anything loose/leaking, I'll give you a shout. Can you pls pm me your number.

[fridayman Senior Member Find all posts View Profile Close fridayman]

If you have a shuttle valve style boost controller maybe give it a clean and make sure the check valve is free and not worn. They have a tiny hole in the body of them which might need cleaning too.

End thrust on the turbo should be 0.15mm or under.

Radial play should be 0.11mm or under (you measure this through the oil feed hole)

Mick

I have a turbotech controller. I'll add it to the list of things to check/clean before I open up the turbo. Although with nearly 300k on the clock I am curious to see what condition the turbo is in...

I do have a slightly bodged hose setup between the turbo and intercooler, so that will be the first thing that I swap tomorrow (the new hose is waiting in the shed).

The fact that it starts and stops so quickly while the boost is still increasing, and it can't be made longer by varying acceleration/boost is what makes me think it might be specific turbo rpm related. I was also thinking it is some sort of harmonic sound.

[fridayman Senior Member Find all posts View Profile Close fridayman]

As suggested, the problem was down to a leak. It was the dodgy turbo to intercooler hose that I had temporarily bodged together when I fitted the intercooler. With the new correct hose fitted the noise is gone. Nice and easy.