Engines become really loud

[PlenumBiscuit]

My VS of 345,000kms lol seems to be running louder than normal

It runs smoothly is quite zippy and responsive but but sitting in the cabin its starting to sound like a tractor haha

I changed my mounts within last 2 years ive put fresh 20/50 oil in on weekend. I cant see any cracks in exhausts manifolds. Checked all vaccum hoses and airbox

Dont know what else to look for

If put ear to plenum it sounds like a big rattle box in there

Its most noticeable when not accelerating. Whether it be rolling or sitting idle the decibels are higher than normal im sure of it

 

[greenacc]

At those k's it could well be an internal issue. Low oil pressure, worn lifters, rockers, pushrods etc..

 

[PlenumBiscuit]

My ecotec of 346,000kms lol is not as quiet as it once was

On idle and sitting in the cabin it sounds as loud as a tractor

Its still runs smooth and is responsive and zippy but when im not accelerating the decibels are quite loud

Ive put new mounts in about 2 years ago, ive checked vaccum leaks and cant see any holes in exhaust manifold

If put ear to the plenum it sounds like a big rattle box in there

Its got fresh oil and newish sparks

I remember when i got it after having a VL how impressed i was by the quietness of the VS but now its like an army tank lol not that bad but...

Is there anything commonly known that i could tweak

the inlet gaskets are new about 4 years and mot losing coolant

Exhaust seems to blow a lot of smoke and fair bit of black soot on exhaust tip

Main seal leaks slowly

No errors on paper clip

 

[PlenumBiscuit]

Thanks mate

I thought this post got deleted as i accidently put it in my ride section

 

[Immortality]

I've done high ratio rockers on a few ecotecs now and each time I've pulled the old rockers off I've found worn push rods. If this gets bad enough it will cause a noisy engine. Since I put new high ratio rockers in the missus L67 with a new set of push rods it's quietened down a lot Worth checking I'd say.

A lot of black soot would indicate it's running rich too. Clean the MAF, run some injector cleaner etc. How old are the O2 sensors?

Our old VS used to sound like a tractor when you first started it up, once the exhaust heated up the leak at flexi joint sealed up and it sounded normal again.

 

[hako]

Could also be a shot harmonic balancer rattling.
Low oil pressure should bring the oil light on at idle also light will stay on for a few seconds longer than usual after starting.
If it was a cracked exhaust manifold or leaky gasket you can usually notice the blast marks that the hot gases leave as they exit.

Good Luck.

 

[harrop.senator]

Balance shaft rattles pretty common too also seems to wear pushrods when it becomes dicky.

 

[PlenumBiscuit]

Thanks some interesting info there

I read up a little about pushrods sounds like an easy job to do? I can do most thing but pulling the heads apart or timing belt off id ruin the car

However pushrods arent that deep inside hey just take a rocker off and the rods come out?

O2's are about 4 years old ive cut the pink wires too lol

I changed my cas about 3 months ago and HB seemed fine

Does stock vs hav a flexi point on exhaust never noticed one and google dont show many

Getting new tools soon so might do a couple of exhaust gaskets

Yea i asked mechanic about balance shaft bearing he said its a very big job to do

Also i saw a thread once about some little ticker thing on the timing belt once and it mentioned it causes a lot of noise and can be taken off anyone know what im refering too

 

[Immortality]

MY bad, it's not really a flexi joint as such. It's where the merge pipe joins to the single system just before the Cat. It's held together with 2 bolts which are spring loaded. All this only applies if you still have the standard exhaust system fitted.

The V6 has a timing chain, it's common enough for the timing chain tensioner to wear out/fail and end up in the sump and then the timing chain is really sloppy which can create some noise. Use a long screw driver like stethoscope to diagnose. To fix a new tensioner will need to be fitted requiring the removal of the front timing cover.

Yes the balance shaft bearings are a big job but less likely to be an issue than it was on the older 3800 V6 engines because the rear needle roller bearing is pressure fed oil. Can normally determine a balance shaft bearing issue by using a long screw driver like a stethoscope and listening at the back of the engine in the middle of the valley area between the top 2 bell housing bolt locations. If the balance shaft is an issue than the simplest solution is to dis-engage it by removing the drive gear from the front of it and leave it in place. This would require the timing cover to be removed from the front of the engine.

Push rods are by far the easiest of the jobs to do on your list.

 

[PlenumBiscuit]

awesome immortal

is there anything else under the rocker covers i could renew without having to take timing covers off

am going to wreckers today to get a feel of the setup

sometimes my mechanic says thats just noisy tappets, whats would he be referring to there? lifters, rockers, pushrods?

id actually wouldnt mind looking at timing belt & tensioner, just getting the HB off and on is my hurdle