increasing idle vibration

aoleks

aoleks

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Hi all,

2008 2.0 TDI 143hp CAGA engine code
132k miles, well maintained (castrol edge only once every 6 months or 10000 miles, whichever comes first, mann filters, all fluids replaced yearly, brand new sachs DMF + clutch + bearing + slave cylinder, new timing belt + water pump + tensioner + pulleys (dayco), shell v-power only!!! etc.)

car pulls like a train and the fuel mileage is great. exhaust is like new even though I'm on the original DPF. no errors in computer, last time I took it to the Audi specialist in Harrow they said injectors had very good values.

the only problem is that I have an increasing vibration at idle. needle is perfectly stable, car always idles at 800rpm (except for regen), but there's a vibration that can be felt in the cabin, along with an irritating whine when accelerating.

I looked at the engine at the auxiliary belt tensioner seems to be dancing. also, the crankshaft damper seems to be uncentered. power steering vibrates at very low speeds + idle. can't see anything suspicious on engine mounts, but haven't looked really well.

auxiliary belt + tensioner + idle pulleys are brand new (dayco) and have been installed correctly, crank damper and alternator clutch are old.

I suspect alternator clutch + crank damper OR engine mounts. what do you think? how do I test?

thanks
 
Sounds like engine mounts to me, check for visible fluid leaks, should be able to pick it up with a scan too.
 
engine mounts are hydraulic and have sensors I think.

Perhaps an engine mount is throwing a fault code?
 
I have similar problems and my vw specialist is suggesting bad engine mounts after the test drive. Steering wheel vibration at idle is a common character of these cars and not a fault

Sent from my SM-G928F using Tapatalk
 
i had same issue with mine, changed all pulleys, belt and tensioner, i even changed timing belt and tensioner, still had the vibration. it was only when i took gearbox out to replace clutch and dmf that i noticed os engine mount was clapsed, once i replaced the mount it was like a new car, so smooth
 
can the engine mount be bad without throwing an error? after reading about it, it seems that only the passenger side mount is electronic, the other one is just a piece of rubber. am I correct? :)
 
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aoleks said:
can the engine mount be bad without throwing an error? after reading about it, it seems that only the passenger side mount is electronic, the other one is just a piece of rubber. am I correct? :)
Click to expand...

Engine mount failures do not throw up a CEL light, they will only show an error stored in the ECU that is seen on a VCDS scan. So unless you get a scan done by someone who has VCDS or a proper dealer tool you will never know.

As for which mounts have sensors, on some cars it's one on other cars it's both, but from what I understand most of the time it is just one and that one tends to be the passenger side.
 
Hi. I know the mounts don't throw any CEL engine light, but I have VCDS. No errors show up. That's why I was wondering if both mounts are electronic.

Is there any way to find out?
 
aoleks said:
Hi. I know the mounts don't throw any CEL engine light, but I have VCDS. No errors show up. That's why I was wondering if both mounts are electronic.

Is there any way to find out?
Click to expand...

You can get under the car and look at them. If they have an electrical connector they are the sensor type, if they don't then they are not.

Also, on my B7 A4 the passenger side mount has clearly leaked, as there is a red-ish / pink stain all over the mount which is the classic sign of the fluid leaking out. However....no errors in VCDS for engine mounts! Even though I can see that sensor has an electrical connector. Maybe not all the fluid has leaked out, maybe some other reason why I don't have codes, who knows.

However, what I'm getting at is that nothing beats a proper visual inspection. The sensors will not always throw a code, even if upon inspection it's clear they have failed.

So best thing to do is get under the car and have a look for yourself.
 
aoleks said:
can the engine mount be bad without throwing an error? after reading about it, it seems that only the passenger side mount is electronic, the other one is just a piece of rubber. am I correct? :)
Click to expand...

Mine didnt have any sensors, it was os one thay went down but i coudnt see anything wrong until the gearbox was out
 
quick update: it's not the belt, not the pulleys, not the mounts. it was oil pump on it's way out...

this engine is notorious for this problem, but mine seems to have lasted a lot more than all the others (137k miles).

hopefully I only need to change the shaft driving the oil pump with the new version, which is £11...

I'm sure I can do the work myself, so hopefully it won't be an expensive thing.

how much is an oil pump btw? I want to change it anyway, if I take half the engine apart.
 
http://www.kmbpartsdirect.co.uk/oil_pumps.html

Kit 9 from the above, change the shaft at the same time, not just the drive, otherwise the shaft will wear on the new drive and will end up with the same problem and double the work. Do the job right first time!

They also sell new oil pumps for circa £180 on the same page.
 
I was thinking to change the drive shaft (hexagonal one) and the oil pump. Febi does a kit for £115 delivered. What's the point in getting a brand new balance shaft?
 
The problem is the balance shaft AND the key are made of soft material that doesn't fit very well. So over time the hex key will wear and the internal hex of the shaft will wear, as you are experiencing. However, if you simply fit a new hex key (newer ones are hardened) then what happens is the hex receptacle in the balance shaft will begin to round off more and more, so you end up with the exact same issue where the pump is no longer being driven and you lose oil pressure, even though the new shaft will fine, the receptacle wont fit it any more.

Basically you have 2 failure modes and replacing the hex shaft only fixes one of those, replacing the balance shaft and the hex drive fixes both.

It's not a small job, the whole subframe needs to come off on the B8 (can simply lower it on the B7), so do the job once and do it right. KMB Parts (I linked to above) take old worn balance shafts, fit a longer (100mm) hardened key way, weld it in place, machine it all smooth and flat, then supply a brand new OEM VW / Audi 100mm hardened hex key. You will not get any better than this.

Audi only sell full balance shaft modules for circa £1200 + VAT, hence KMB do it on an exchange basis of £215 + £125 deposit that you get back when you return your old balance shaft. Deposits are returned quickly, I got mine back in the evening, the same day the received my old balance shaft.

I have just done it on my B7, the old one was a very sloppy fit and was showing signs of wear / rounding, but the new one is tight as a drum.

Do will need to lock the engine at TDC and get a timing tool for the balance shaft module, it all needs to be timed up properly. You also need some special Audi tools to ensure the subframe is properly lined up when re-fitting.

The timing tools are made by Sealey and are cheap, but the subframe tool is an Audi only part. I got mine from a supplier in Germany, but was still only about £25, and then you need a 100mm long ball ended allen socket to undo the 2 bolts near the gearbox for the sump.

You also need 1/4", 3/8" and 1/2" torque wrenches. The balance shaft needs to be torqued down in stages (hand tight, then 6nm, then 20nm, then another 90*) and the subframe bolts, etc are all torqued to yield. So a lot of bolts need to be replaced as well.

Think I spend about £80 on bolts and £20 for the proper VW / Audi sump sealant.

Like I said, it's a big job, so do it right first time and ensure it's the only time you need to do it.
 
Last edited:
I understand, it makes sense now. The only problem is getting the subframe off. I thought it was a matter of removing the oil sump. Does the suspension need to come off?
 
I have added more info you my last post, so you might want to re-read it.

To remove the sump, the subframe needs dropped, it passes right over the sump and prevents you removing it and gaining access to bolts until it's out of the way.

I will look on ElsaWin when I get home and get more info for you. On the B7 you just need to lower the subframe, but last I read, the B8.5 (2013) requires the subframe to be totally removed according to ElsaWin, so I suspect a 2008 B8 will be the same.
 
I do have the timing tools, as I changed the timing a while ago. I have threebond gasket silicone, which I used before in many vehicles and is the only thing I trust. I have a torque wrench and all the required sockets, but I'm not sure how tight the subframe bolts have to be, I might need to buy another wrench (mine only goes to 150Nm). Bolts will be replaced anyway... I was planning to change the oil pump too, but I don't see anyone mentioning that. It's mainly the shafts that fail, right?

I have all the official workshop manuals at home (bought them from Audi for this particular car, updated in 2015). I will do my homework and see what exactly needs doing. It looks like I'm in for a lot of fun...
 
aoleks said:
....but I'm not sure how tight the subframe bolts have to be, I might need to buy another wrench (mine only goes to 150Nm)....
Click to expand...

Not sure on the B8, but on the B7 it is 110nm + 90*
 
right, I printed out the relevant pages. everything is sweet and simple and I have all the tools, until I get to removing the subframe...

now there are 2 things: the subframe and the brace connecting to the subframe. the brace is easy to get off and as far as I can tell, the brace is the only thing preventing access to the sump. I can't visualise the subframe being in the way, but I'll have a look this weekend. thing is, the front will have to come off as well, as I need access to the timing belt too.

my main dilemma is not knowing what to do in terms of cost. do I invest hundreds of pounds in tools, bolts, silicone and another couple of hundred for the right parts on a car that's 10 years old and did 137k miles? do I sell it as it is and buy something else?

any sensible advice?
 
I'm sure from my time over in the B7 section there was a company mentioned a few times that did the job complete for a not too excessive cost considering the work involved ??

Might be worth a browse in the B7 forum.....
 
aoleks said:
right, I printed out the relevant pages. everything is sweet and simple and I have all the tools, until I get to removing the subframe...

now there are 2 things: the subframe and the brace connecting to the subframe. the brace is easy to get off and as far as I can tell, the brace is the only thing preventing access to the sump. I can't visualise the subframe being in the way, but I'll have a look this weekend. thing is, the front will have to come off as well, as I need access to the timing belt too.

my main dilemma is not knowing what to do in terms of cost. do I invest hundreds of pounds in tools, bolts, silicone and another couple of hundred for the right parts on a car that's 10 years old and did 137k miles? do I sell it as it is and buy something else?

any sensible advice?
Click to expand...

As for whether or not it's worth it....I did it on my B7 and that car is worth less than yours. When it comes to tools, I don't know about you, but I look for any excuse to buy them, and it's something I will have well beyond the job I originally bought then for, so it's a bit of an investment. Some of the special 1-off Audi tools can just be resold on eBay to recoup some of the money.

Overall, spending a few hundred is going to be cheaper than replacing the car, but whether it is worth it to you is something only you can decide.

Thing with the subframe is the beam that runs left to right which connects the 2 sides together sits right under the sump. So that's why you need to lower it to gain access. See image of a subframe below. That beam in the middle is causing all the headache.

563c830cae84c_ori.jpg



gary_a4_quattro said:
I'm sure from my time over in the B7 section there was a company mentioned a few times that did the job complete for a not too excessive cost considering the work involved ??

Might be worth a browse in the B7 forum.....
Click to expand...

That would be the garage KMB Parts Direct use. KMB supply the modified shafts and their recommended garage was doing the job for circa £350-ish if I'm not mistaken. All done and dusted in a morning.

They are based in Sheffield if that is anywhere near the OP?
 
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Ah yes, I've heard of Ring Engineering, they are meant to be good also and I've seen a few guys recommend them, but not used them myself personally.
 
The last B7 I worked on with this problem had all the balance shaft assembly removed and the oil pump replaced with a chain driven unit from the older indistructable PD engine,,, don't know who did the work or what it cost but imagine my surprise after a days work stripping it all down to inspect the Hex shaft, which was no longer there... On another note and whilst I do hope you have found your problem did you have the alternator freewheel pulley changed when you had the tensioner and ancillary belt changed ?? the alternator has a clutch assembly inside it's pulley and this seizes in time and causes the tensioner to dance around as you called it, this makes idle noisy , also makes the power steering noisy on full lock and also on my current car caused what felt like clutch judder when setting off in first, changing this one £40 part cured 3 separate problems on my car
 
I didn't replace the alternator pulley, but was on my to-do list as I know it causes issues.

Regarding my problem, I'm confused. Spoke to fire engineering yesterday, £650 to do the work. That's if turbo and main bearings are food. If turbo gone, another couple of hundred. If main bearings are gone, I still pay £300 and decide not to fix.

I can also "risk" the £300 and buy parts and tools and attempt myself. Another option I need to think about is brand new engine, found one on ebay for £1400. The only downside is, how will that work with old injectors and dpf?

What to do, what to do?
 
Personally, I would buy the tools and bits and do it myself for £300 if you have time. Reason is that if you pay someone else £300 and it's had it, then that's £300 down the pan, where as tools you buy can be kept and used in future, so more of a long term investment, regardless of what happens with the car.

Also, you don't need to buy any parts (subframe bolts, KMB Balance Shaft kit, etc) until after you have the car stripped down and can see if it's worth paying for that stuff or not.

As for a replacement engine....I wouldn't have thought old injectors or DPF would be an issue to be honest. As long as they all work and the ECU is happy, I don't see there being a problem, but I am not an expert, so there might be something I am missing.
 
not the oil pump, the shaft driving the oil pump. at least that's my theory. it fails under normal circumstances, just by driving the car. keep in mind I was at 137k miles, which is not little. I'll know more when I actually take the pump assembly out, if I manage to do it.
 
aoleks said:
not the oil pump, the shaft driving the oil pump. at least that's my theory. it fails under normal circumstances, just by driving the car. keep in mind I was at 137k miles, which is not little. I'll know more when I actually take the pump assembly out, if I manage to do it.
Click to expand...

Have you actually had the "Low Oil Pressure" warning appear on your dash? Or are you doing this as a precaution? As that's something we haven't fully established yet.

Reading between the lines it does sound like you had the warning show up on the dash. Could also be worth putting a mechanical oil pressure gauge on it or at least testing the current sensor to confirm it is indeed low oil pressure and not just an electrical fault.

Either way though, I would be changing the current shaft & 77mm hex for a modified shaft & 100mm hex.
 
initially the low engine oil light came up, which is why I drove another 2 miles until I found a safe spot. I had this light before and it was indeed little oil in the engine, had to top up a bit (nothing extreme, just your occasional top up). I switched the engine off, checked the oil dip stick and it was exactly between the lines, so all good there. engine was hot, so maybe the reading was higher than it actually is, but that doesn't explain the low pressure. that's when I felt something's wrong. second time I started the engine (2 minutes after), I got the low oil pressure light and the engine sounded slightly different. it wasn't vibrating more than usual, it didn't sound clicky, it just felt as if there's not enough sound insulation, if you know what I mean.

I have 3 options really, as I'm going through major changes in my life and can't afford a new(er) car:

1. attempt to fix myself, see if turbo and main bearings are damaged, if not continue and fix it cheap. £400-500 (estimate)
2. attempt to fix myself, can't do it, let mechanic do it, continue if no other damager. £650 or £300 is decide not to continue due to damage.
3. buy brand new engine and turbo, replace and have a "new" car for the years to come. £2000 (estimate)

I'm still researching options and making phone calls. it it wasn't for the ****** subframe, I would've been done already...
 
Ah, fair play. You know my stance. Option 1 or 2 first, then only if the engine is goosed go for option 3, don't pay all that extra money if there is no need to.

If I was closer to you I would have helped out and let you use my tools / garage no bother, but I'm all the way up in the NE of Scotland! So no use I'm afraid.
 
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