screeching noise!!!!

[toyotav84x4]

Great to hear all fixed Sandgirl!

You have reminded me to fix mine.........soon.

[M35A2]

There have been a few of us with the same problem. Mine still does it since head replacment. Could be a belt but almost the same sound appears to come from the turbo when failing (bearing wear causing blades to hit the sides) or an air leak around the same area.
One guy said the inlet manifold gaskets didn't seal properly and a bit of instant gasket did the trick.
I'm sure mine is the turbo but I do have a small blowby on the exhaust manifold which may be causing the multi layers steel gaskets to whistle.

I don't think it's your turbo mate. The turbine spins at 10's of thousands RPM a minute. If the blades hit the sides the turbo would be fu*ked.

I have to say I've not had this problem with mine since putting my head on. Have you checked the torque of your manifold nuts?

[toyotav84x4]

The reason I was thinking the turbo was that the truck uses a small amount of engine oil over time. I hope its not the turbo! I have noticed that the sound goes away at first if its been driven in the wet? This suggests a belt but the sound is up the top side of the turbo. If I can just get the time to have a good look. Head change was 6 months ago now so from what you are saying the turbo wouldn't last that long if really bad!

[M35A2]

The reason I was thinking the turbo was that the truck uses a small amount of engine oil over time. I hope its not the turbo! I have noticed that the sound goes away at first if its been driven in the wet? This suggests a belt but the sound is up the top side of the turbo. If I can just get the time to have a good look. Head change was 6 months ago now so from what you are saying the turbo wouldn't last that long if really bad!

A turbo can suffer wear, or go without warning. Do you idle your engine for at least a minute EVERY time you shut the engine down? But, if the blades hit the sides at 80,000 RPM the turbine blade would explode into a thousand bits.

Use a long screwdriver and put it up against the turbo when it's making the noise then put your ear against the end of the screwdriver. This acts like a stephoscope and you can hear where the noise is.

After an oil change does the sound get really bad until the oil pressure has built up?

[toyotav84x4]

Yes I do idle the enging before shut off for about 30 seconds or more if just in from the motorway or towing.

The sound is mainly under light acceleration, and towards the 2250 rev point. In fact the sound appears/increases to the higher reves in 1st gear and then disappears when the auto kicks up to second. I did try the long screwdriver a while back but it just seems too noisy in there to tell?

If I give the engine a bit of a thrash about in the lower gears the noise will start to disappear. I thought this would be the turbo getting more oil and preventing the bearing tolerances from causing play. The general oil pressure on the dash appears to be good like everyone elses with a 3.0.

I had better get in there and sort it out step by step but it has got no worse in 6 months.

[stormforce]

The bearings on my turbo went at xmas on my way home from Salisbury and it sounds like a tin of nails rattling.The rattle got worse as the revs increase.There was quite a bit of play on the shaft when i checked it and was surprised it was still in one piece

[coolsv650]

There have been a few of us with the same problem. Mine still does it since head replacment. Could be a belt but almost the same sound appears to come from the turbo when failing (bearing wear causing blades to hit the sides) or an air leak around the same area.
One guy said the inlet manifold gaskets didn't seal properly and a bit of instant gasket did the trick.
I'm sure mine is the turbo but I do have a small blowby on the exhaust manifold which may be causing the multi layers steel gaskets to whistle.

I had exactly the same noise.... it turned out to be a exhaust blow on the No4 cylinder that had nearly burnt through the gasket. Replaced with a spot of grease did the trick

[toyotav84x4]

Thanks Guys
Lots of good advice here and I don't think it's the turbo but a gasket rasping noise. Looking briefly today I can see some blowby on the exhaust manifold against the head. I think it must be a warped manifold. I guess I will pop it off and grind it level although that's not the best of fun from memory.
Also the turbo whistles perfectly all through the revs with no other rattle sounds as suggested from bad bearings.