# Loud tractor noise from engine



## jonnyl888 (Dec 10, 2012)

Hi, after a long hard drive today there is suddenly a rattling noise coming from the back of the engine, sounding like an exhaust leak. When I bought my TT in nov, it made a similar but quieter sound only above 3000 rpm when the turbo would kick in. However after ragging it today, the noise has gotten louder and occurs at around 2000 rpm. Initially I thought the worst and believed a bearing in the turbo had gone. But after driving it a bit more, my boost gauge is reading fine. Giving max boost of 1 bar. Which means the turbo is running fine... Anyone any ideas? Gonna have a look at it tomorrow, just wanna know what to look out for.

Thanks


----------



## NotFromSomerset (Nov 11, 2012)

Sounds like the heat shield has come loose under the car. Common problem. Get the front jacked up and rip it out


----------



## V6RUL (May 28, 2009)

+1 visual inspection required.
Steve


----------



## jonnyl888 (Dec 10, 2012)

Gonna have a look at it today after lunch, it's not so much a rattling. Sounds like a tractor...


----------



## jonnyl888 (Dec 10, 2012)

Hi,

Ok so was under my car for 5 hours today, and couldn't find anything. Except some oil on the base of the oil sump and transmission which I don't know is new or old oil from messy oil changes etc. There doesnt seem to be an oil leak on the ground. The exhaust looks fine, there is no heatshield on the cat. Since I bought the car it has been consuming oil, whether it is burning it or leaking somewhere I don't know.

On Monday I took the car out for a drive when suddenly oil pressure light came on. I drove it gently for about a mile where I could safely stop and quickly topped up. Since then, the tractor noise has gradually gotten louder until 2 days ago when it could be heard on idle, and even worse when revving. However the turbo is fine, and can run at 1 bar boost.

Does anything have any idea or experienced anything like it before. I hope it's just an exhaust leaking but I can't tell. If the turbo was starting to fail, I wouldn't get full boost would I? How do I go about checking whether the turbo oil feed pipe is blocked?

I'm going to upload a video of the sound, for anyone to relate to.

P.S. I want to leave going to a garage as a last resort as I'm a bit tight on cash right now. So I would rather pin point the problem first before paying anyone to check it.

Thanks


----------



## Hoggy (May 8, 2002)

Hi Jonny, when did you last check oil level before the alarm came up. 
I would get the oil pressure checked as oil pressure may be low, not low enough to bring up alarm but low enough to cause extra wear & rattle. Sump off next I would think,to check sump strainer @ least.
Hoggy.


----------



## jonnyl888 (Dec 10, 2012)

I check it every two weeks or before long journeys. If I really floor it, the oil will drop quicker.

After some extensive research, I have found two other people with the same problem.










That's what it sounds like, like a tractor/old diesel engine. Their conclusions are the hydraulic belt tensioner. How does one of these fail? If it does will it cause the belt to slip and ruin the engine?


----------



## J•RED (Feb 10, 2013)

Is the oil pressure light still on? First thing I would be doing is taking the sump off and having a look at oil pump, strainer and pick up pipe. If the tensioner fails then yes your pistons will collide with your valves and will be an expensive list of parts and labour.


----------



## jonnyl888 (Dec 10, 2012)

No the oil pressure light turns off when I top up. What would cause it to lose oil? The oil level on the dipstick goes down every few hundred miles, if the pump/strainer is blocked it wouldn't pump at all and probably would have killed the engine already right?

I'll have a look at it first, to see what's in there anyway. And give it a clean. 

Thanks


----------



## Hoggy (May 8, 2002)

Hi Jonny, the oil pressure could still be low, but not low enough to bring up low pressure alarm. 
Get it checked out & sorted ASAP.
Hoggy.


----------



## jonnyl888 (Dec 10, 2012)

If anyone else is interested, here are a few links that I've been reading through:

viewtopic.php?f=2&t=178279&start=75
http://www.pistonheads.com/gassing/topic.asp?t=866754

And also
http://www.audi-sport.net/vb/a4-s4-foru ... ymbol.html

(he seems to be getting a tractory noise as well)


----------



## roddy (Dec 25, 2008)

as said,, the first thing to do is get oil pressure checked,, fit a guage, i dont know it it can be done via vagcheck


----------



## jonnyl888 (Dec 10, 2012)

How would I go about checking oil pressure?

I have a turbo boost gauge fitted, any chance I can relay that to check oil pressure?

UPDATE: It was the oil level light that came on NOT oil pressure light. Sorry didn't know there was a difference.

ALSO: I get this on start up. 



 then it goes away after driving. Well it used to... Now the tractor noise is too loud and covers everything. Bad kombi valve? What is that?


----------



## Hoggy (May 8, 2002)

Hi, To check oil press, a pressure requires fitting in place of or Tee-ing in to oil press switch.
Engine doesn't sound good, but some of that noise is coming from a belt drive, either being driven by cam belt or ribbed belt. 
Hoggy.


----------



## jonnyl888 (Dec 10, 2012)

Ok, so this is my car  :


----------



## Hoggy (May 8, 2002)

Hi Jonny, That sounds like an exhaust leak.
Hoggy.


----------



## .Griff. (Dec 17, 2011)

Hoggy said:


> Hi Jonny, That sounds like an exhaust leak.
> Hoggy.


I was just about to post the same. Sounds like a leak from the exhaust manifold to me (I'm no expert mind..)


----------



## jonnyl888 (Dec 10, 2012)

Really? I really hope so, how easy is it to access the manifold?

It can't be between manifold and turbo because I'm still get full boost pressure. Is there a way to check for exhaust leaks e.g. put some dry ice in the system and see if it comes out? 

Just removed oil sump and cleaned it out, it was looking fine, the strainer had hardly anything in it. Tiny bit of sludge from previous oil in the corner of the sump. BTW, how bad is it to leave the sump off? The car is out on my drive way, but I won't be able to put it back till tmw.


----------



## roddy (Dec 25, 2008)

it is no prob at all,, could be a bit messy by morning tho


----------



## roddy (Dec 25, 2008)

the ex manifold is not easy to access


----------



## jonnyl888 (Dec 10, 2012)

roddy said:


> the ex manifold is not easy to access


any tips on getting there?

my plan:
- remove turbo charge pipe
- remove brackets, and heatshields
- it should be there right?


----------



## kazinak (Mar 23, 2010)

Check egt and lambda sensors, maybe one of them is loose, both of them next to exhaust manifold.

Sent from my LT18i using Tapatalk 2


----------



## ElTurn (Apr 9, 2013)

Dude - get it checked by a recommended (independant) garage. You've a lot going on by the sounds of it and if you aren't sure and have diagnosed by Internet you could be replacing unnecessary parts, which goes against your lack of cash.. Also, what if your engine goes pop in the mean time? That won't be cheap..


----------



## jonnyl888 (Dec 10, 2012)

I'm not changing anything till I'm sure, what's wrong with having a look myself? I'm learning a lot about the car.


----------



## roddy (Dec 25, 2008)

jonnyl888 said:


> I'm not changing anything till I'm sure, what's wrong with having a look myself? I'm learning a lot about the car.


you can check of course,,, it might be worth trying the old plastic tube method to see if you can locate the noise,, easier than striping things off


----------



## jonnyl888 (Dec 10, 2012)

Just took off charge pipe, and stuff around it and got to the exhaust manifold. On it there is a loose bolt??? What is this for? And why is it loose? And could it be causing the horrible noise?

EDIT: Are these the bolts that hold the turbo on? Looks like someones played around here before...


----------



## holla_j (Jan 1, 2012)

My car makes same noise, topping up the oil seems to cure it. I heard somewhere its a oil return valve that causes the noise when turning the car on but I have yet to change it. Hope you get it sorted, I'll be keeping a eye on this thread so I can get mine fixed.


----------



## jonnyl888 (Dec 10, 2012)

My suspicions confirmed, it is an exhaust leak... The bolt above (holding the turbo to the exhaust manifold) has sheared off. Looks like it slowly rusted through. Note that these are not OEM bolts, the previous guy who worked on the turbo must have put the wrong type of bolt in, which couldn't withstand the high temperatures and just gave up.

Time to remove exhaust manifold, turbo and drill the rest of it out. Hopefully the thread in the turbo is fine. [smiley=bigcry.gif]

BTW how do I find out part numbers for these bolts and gaskets?


----------



## brooksesi (May 8, 2012)

Very annoying, but at least you have a solid diagnosis of the problem. If that was the work of the previous owner, there is a high chance they didn't replace those bolts, as I'm sure those are stretch ones that are supposed to be replaced.


----------



## jonnyl888 (Dec 10, 2012)

Spent two more hours trying to get to the bolts on the manifold... Such a headache, any tips on removing the exhaust manifold?

How do you remove this metal piece on top of the manifold (labelled 26)


----------



## jonnyl888 (Dec 10, 2012)

Tightening the bolt didn't help, took it to a garage and they say the gasket between turbo and exhaust manifold has had it. Is this an easy job to change. I'm guessing you don't need to remove the manifold do you? Surely you can just take out the 3 turbo bolts remove the old gasket and slot the new gasket in?


----------



## jonnyl888 (Dec 10, 2012)

Ok just sorted the problem out, wrote a how to here

http://www.ttforum.co.uk/forum/viewtopic.php?f=2&t=330416&p=2580483#p2580483


----------

