bad alloytec rattle only at 3000rpm+

[oi nah]

Get the intake off. Get the injectors off. Remove the lower intake gasket. That will be one place if you are convinced that’s the location of the sound. It is combustion pressure you are hearing. Not mechanical.

However, rather than fk about with guesses do a smoke test and without removing a thing and 30 mins of your time, you locate the exact place or places and be able to do a quick targeted repair and solve the issue. Unless that’s a head gasket, it won’t be quick.

One thing that is weird about it is as soon as you give it any revs the noise goes away, it’s only at idle, not sure if that’s from an increase of pressure making it go away. But yeah I’ll have a look at trying to make a smoke machine soon, or taking it in somewhere. I don’t think it should be a compression issue because it drives fine, and no check engine codes about compression, purley just o2 sensor codes. But yeah if it’s a head gasket that’s gonna be a pretty big job

 

[oi nah]

Get the intake off. Get the injectors off. Remove the lower intake gasket. That will be one place if you are convinced that’s the location of the sound. It is combustion pressure you are hearing. Not mechanical.

However, rather than fk about with guesses do a smoke test and without removing a thing and 30 mins of your time, you locate the exact place or places and be able to do a quick targeted repair and solve the issue. Unless that’s a head gasket, it won’t be quick.

But what do I do once I’ve got the lower intake manifold off, are you talking about replacing the gasket for it? I did take that gasket off when I did the cams

 

[Fu Manchu]

But what do I do once I’ve got the lower intake manifold off, are you talking about replacing the gasket for it? I did take that gasket off when I did the cams

Yes, great. However there is a huge leak. Let’s first hope it’s the lower gasket on the intake.

Or you have a leaking exhaust manifold. Either from a poorly fitting gasket, or a crack.

There is a problem. In order to eliminate the possibilities you need to confirm they are good. That is different to assuming they are good.

Smoke test would confirm the leak and it’s/their location. If a smoke test is not going to get done, then it will involve more labour going back and redoing things and doing it really well. That is what needs to be done. That is working on cars.

 

[Fu Manchu]

One thing that is weird about it is as soon as you give it any revs the noise goes away, it’s only at idle, not sure if that’s from an increase of pressure making it go away. But yeah I’ll have a look at trying to make a smoke machine soon, or taking it in somewhere. I don’t think it should be a compression issue because it drives fine, and no check engine codes about compression, purley just o2 sensor codes. But yeah if it’s a head gasket that’s gonna be a pretty big job

Just because it drives fine doesn’t mean it’s fine. If it drove fine, you’d not have a problem. You have a problem.

Look here’s a case in point where the car drove “fine”. Posted today. A VZ misfire. Owner had loaded the parts canon. Fired it. A few workshops couldn’t find the fault because they don’t have the diagnostic skills.

Blown head gasket.

This is the equipment and skills needed to fault find cars made in the last 20years. Thats just how it is.