Thread: Noise when accelerating

Originally Posted by Brett1066

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Also, when I replaced the turbo, I noticed the exhaust pipes were coated in soot - would this be due to a blown gasket, or is there something more sinister going on?

I reckon that you have leaking exhaust manifold issues.

Sounds like a boost or vacuum leak.
Check the rubber hose from air cleaner to turbo, mine split to the left of the join in the middle, made a whistle when on boost due to the higher vacuum.
Check all the hose connections again.

A thin layer of carbon in the exhaust manifold I'd say is normal.

When I changed the turbo to a water cooled ball bearing (MTS) unit on my 300Tdi Discovery, I also found a noise like a loose pipe - turned out that is just intake noise - the new turbo is a lot noisier than the old one, you eventually get used to it they told me.

I thought it was a leaky exhaust manifold, and the new gasket blew not long after the turbo was installed due to one of the exhaust studs being stripped and not tightening properly, so yesterday I pulled the turbo off and put a layer of high temp copper gasket sealant around where it had blown, hoping this would fix the problem, but to no avail
As this is my daily drive, will it cause any problems (apart from my sanity having to listen to that damn noise) to keep driving until I get a new gasket and studs? Only driving about 10kms each way, so not far enough to build up any real heat.

Will check out the hose from the air filter to the turbo, apart from tightening up the clamps I haven't given it a good going over, so will do that this arvo

Originally Posted by Brett1066

I thought it was a leaky exhaust manifold, and the new gasket blew not long after the turbo was installed due to one of the exhaust studs being stripped and not tightening properly, so yesterday I pulled the turbo off and put a layer of high temp copper gasket sealant around where it had blown, hoping this would fix the problem, but to no avail
As this is my daily drive, will it cause any problems (apart from my sanity having to listen to that damn noise) to keep driving until I get a new gasket and studs? Only driving about 10kms each way, so not far enough to build up any real heat.

Will check out the hose from the air filter to the turbo, apart from tightening up the clamps I haven't given it a good going over, so will do that this arvo

Every turbo diesel engine needs to have its exhaust manifold mounting face machined every 150k kms or thereabouts - that's just the way it is - they warp and even more so if short trips are the norm - a simple fact of metallurgy. A turbo exhaust manifold runs from 20°C at start up to 450°C as soon as you load it up at boost. No gasket sealant will cope with that especially as it runs at about 1.5 bar pressure when it is on boost. A new gasket/studs may help but the manifold should have been trued up at turbo installation - just plain common sense.

Certainly sounds like the boost leak I had when I changed the hoses on mine to silicon. I was surprised how tight the clamps had to be stop it whistling.

Steve

Originally Posted by Daniel

Every turbo diesel engine needs to have its exhaust manifold mounting face machined every 150k kms or thereabouts - that's just the way it is - they warp and even more so if short trips are the norm - a simple fact of metallurgy. A turbo exhaust manifold runs from 20°C at start up to 450°C as soon as you load it up at boost. No gasket sealant will cope with that especially as it runs at about 1.5 bar pressure when it is on boost. A new gasket/studs may help but the manifold should have been trued up at turbo installation - just plain common sense.

I had a new head put in just over a year ago, and she has only done about 5000km since, so I would have thought the manifold face would still be ok. Having said that, given the amount of trouble the big girl has been giving me of late, perhaps it has warped somewhat, point noted.
If it is the case that it has warped, how much a pain is it going to be to get it true again, and is this something an amateur mechanic can do? No slouch with the tools but certainly no tradesman either....

Originally Posted by Brett1066

I had a new head put in just over a year ago, and she has only done about 5000km since, so I would have thought the manifold face would still be ok. Having said that, given the amount of trouble the big girl has been giving me of late, perhaps it has warped somewhat, point noted.
If it is the case that it has warped, how much a pain is it going to be to get it true again, and is this something an amateur mechanic can do? No slouch with the tools but certainly no tradesman either....

Like the others have said, check the obvious first, remove the bonnet and have someone ride in the engine bay listening to where the squeal is coming from. A spray bottle of soapsuds often helps here as well.

The removal of the exhaust manifold will need to be done to replace the studs anyway. Just take the manifold to a local machinist and get him to true it up if it is found to be warped. I paid $25 to get my td5 manifold done.
People pay $100s to get their manifolds ceramically coated and fit larger studs etc but that is not the issue and not the solution.