Smoke and hesitation while accelerating on freeway.

**hemantpd1** · 05-22-2016 02:42 AM

I have a 2007 Audi A4 B7 2.0T. It has 130K miles on it. It used to consume 1 quart of engine oil every 1000 miles.

Recently I replaced following parts by my own:
-Thermostat, because of cooling performance CEL.
-Rear coolant flange as it was leaking.
-Vacuum pump(update version) because the older one was leaking after re-sealing it.

After all these I could see that oil consumption reduced. One day I was cruising at freeway speed and press the pedal little. Suddenly saw a lot of smoke coming out from the exhaust. Car hesitated a little but became fine after few seconds. Now same has happened 3 times in last month. I think it happens only at high speed after diving for some time on highway.

Now I see smoke comes out in the morning on cold startup after sitting overnight. It lasts for few seconds after startup. You can see the video at:

I read through forums and decided to do a dry compression test.

Cylinder 1: 175
Cylinder 2: 185
Cylinder 3: 185
Cylinder 4: 185

The number looks good to me. But I see some oil on the spark plug and at the tip of coil packs. I am considering to replace spark plugs as they look bad now.
Picture at: https://www.dropbox.com/sc/mqlbr00lv...8V1i9l-6nL5Qla

It may be due to valve cover gasket leak. No oil leak on outside, though. PCV looks okay as it is only 10000 miles old and I tested it by blowing air from the end of "C" shape PCV plastic hose. No idling problem.
One more thing I would like to mention here that when the car is idle I hear heartbeat sound near airbox(probably coming from turbo). This goes when car runs. You can hear in the video at:

Car runs great without any other problem. All the services are done on time. My coolant level is ok and the color is consistent. No oil in coolant or coolant in oil.

Any suggestion what could be wrong? Is my turbo starting to wear?

Thanks in advance!

**dalmation53** · 05-22-2016 03:10 AM

I'm having thr same issue as you i got my pcv installed yesterday at dealer for free. Then my valve cover is leaking so i smell it in the cabin like burned oil though it is a simple fix. The other part about your turbo going out i don't know but i did replace my DV and made a world of a difference indeed. Also did you replace you N80?

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**hemantpd1** · 05-22-2016 05:05 AM

Originally Posted by dalmation53

I'm having thr same issue as you i got my pcv installed yesterday at dealer for free. Then my valve cover is leaking so i smell it in the cabin like burned oil though it is a simple fix. The other part about your turbo going out i don't know but i did replace my DV and made a world of a difference indeed. Also did you replace you N80?

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I have not replaced my DV or N80. I will check it tomorrow if they are in good shape. Do you think these can contribute to smoking issue?

**Denio24** · 05-22-2016 01:37 PM

A heartbeat noise in the airbox may also indicate a pcv issue as a result of an excess of pcv gasses going through the rear pcv and into the turbo/intake side of things. It wouldnt hurt to change the diverter valve as well as the pcv valve. Good luck!

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**08 classic** · 05-22-2016 02:22 PM

Do you have a oil catch can? If you do then its normal at idle to hear the valve in the pic tube fluttering. If you have stock pvc, then there could be a problem.

**hemantpd1** · 05-22-2016 04:47 PM

Originally Posted by 08 classic

Do you have a oil catch can? If you do then its normal at idle to hear the valve in the pic tube fluttering. If you have stock pvc, then there could be a problem.

I have a stock PCV. Just checked the breather tube and can see lot of oil inside it. Please see the picture below:

https://www.dropbox.com/s/cuspmn91j2..._0055.JPG?dl=0

Is it normal?

**hemantpd1** · 05-22-2016 04:49 PM

Originally Posted by Denio24

A heartbeat noise in the airbox may also indicate a pcv issue as a result of an excess of pcv gasses going through the rear pcv and into the turbo/intake side of things. It wouldnt hurt to change the diverter valve as well as the pcv valve. Good luck!

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Thanks for your suggestion. Planning to change PCV, DV and valve cover gasket.

**dalmation53** · 05-22-2016 05:29 PM

Originally Posted by hemantpd1

Thanks for your suggestion. Planning to change PCV, DV and valve cover gasket.

I already changed those 2 exept valve cover gasket but car seems more peppy

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**Low and Behold** · 05-23-2016 11:03 AM

I would check your IC hoses because they're likely full of oil thats being sucked through the intake. I chased a similar problem for months on my car - turned out to be the turbo.

**KJack** · 05-23-2016 11:49 AM

I had the same issue. Turned out that I had a crack on the underside of my valve cover. Replacing it made everything better again.

**hemantpd1** · 05-23-2016 02:04 PM

Originally Posted by KJack

I had the same issue. Turned out that I had a crack on the underside of my valve cover. Replacing it made everything better again.

I am planning to change
-VCG
-DV
-New spark plug
-PCV+breatther hose

I hope these will solve my problem. Will update this thread with results.

**KJack** · 05-23-2016 05:57 PM

Originally Posted by hemantpd1

I am planning to change
-VCG
-DV
-New spark plug
-PCV+breatther hose

I hope these will solve my problem. Will update this thread with results.

Inspect the valve cover closely when you remove it to replace the gasket. It's probably cracked. Also be sure to drain the oil that is likely collecting in the intercooler pipe.

**hemantpd1** · 05-23-2016 10:39 PM

Originally Posted by KJack

Inspect the valve cover closely when you remove it to replace the gasket. It's probably cracked. Also be sure to drain the oil that is likely collecting in the intercooler pipe.

Thanks for the suggestion! Parts are on the way from ECS

**hemantpd1** · 05-24-2016 06:00 PM

Originally Posted by KJack

Inspect the valve cover closely when you remove it to replace the gasket. It's probably cracked. Also be sure to drain the oil that is likely collecting in the intercooler pipe.

I drained almost a half quart of oil from intercooler pipes. equal amount from both sides. Is it due to the turbo is failing or VCG? Picture at: https://www.dropbox.com/s/tpu0wgahd5..._0064.JPG?dl=0

**dalmation53** · 05-24-2016 06:11 PM

Originally Posted by hemantpd1

I drained almost a half quart of oil from intercooler pipes. equal amount from both sides. Is it due to the turbo is failing or VCG? Picture at: https://www.dropbox.com/s/tpu0wgahd5..._0064.JPG?dl=0

hard to tell. what happens when you go wide open throttle?

**hemantpd1** · 05-25-2016 02:04 AM

Originally Posted by dalmation53

hard to tell. what happens when you go wide open throttle?

The car is responsive in city riding at low speed. But at highway speed, if try to accelerate(sometimes only) then smoke and hesitation for few seconds and then it becomes normal.

**Low and Behold** · 05-25-2016 10:16 AM

Originally Posted by hemantpd1

The car is responsive in city riding at low speed. But at highway speed, if try to accelerate(sometimes only) then smoke and hesitation for few seconds and then it becomes normal.

The VC is easy enough to take off and inspect. Put a new gasket on it while you're at it. Then clean out the IC pipes as best you can and check on it after a week or so to see if its still collecting oil.

I swapped to a new VC a while back in hopes that it would fix this exact issue, along with a bunch of other shit. Unfortunately it didn't, but hopefully it will in your case.

**KJack** · 05-25-2016 12:44 PM

Originally Posted by hemantpd1

I drained almost a half quart of oil from intercooler pipes. equal amount from both sides. Is it due to the turbo is failing or VCG? Picture at: https://www.dropbox.com/s/tpu0wgahd5..._0064.JPG?dl=0

In my case it was cracked valve cover that was causing oil to dump into the turbo intake and collect in the intercooler pipe. My VC gasket and turbo were fine. The cover itself was the issue due to the crack.

**IC Asmodai** · 05-29-2016 01:25 PM

Have any of you changed to a billet aluminum VC? I'm curios/wondering if this fixes this (what seems to be an ongoing) issue. I have this issue with mine as well, the whole oil loss, smoke when I get on it, and brief loss of power.

Sent from The Lands of Always Winter

**hemantpd1** · 06-05-2016 09:12 AM

Changed the valve cover gasket, spark plugs, coil pack, PCV, breather tube and hoses. Test drove the car on freeway. I always accelerated hard and it did not smoke. But, I will keep checking it. If it does not smoke over a month then I will assume the problem is sloved. Will update the thread.

**hemantpd1** · 06-05-2016 09:19 AM

Originally Posted by IC Asmodai

Have any of you changed to a billet aluminum VC? I'm curios/wondering if this fixes this (what seems to be an ongoing) issue. I have this issue with mine as well, the whole oil loss, smoke when I get on it, and brief loss of power.

Sent from The Lands of Always Winter

Not sure how good it is. You can first change the VCG and see if it solves you problem. I changed PCV and hoses also along with VCG.

**IC Asmodai** · 06-05-2016 05:30 PM

I'll def. try this and thanks for the update. Glad yours seems to be fixed, hopefully it's the same with mine.

Sent from The Lands of Always Winter

**hemantpd1** · 06-10-2016 08:31 AM

Unfortunately, smoke came back yesterday when I was merging onto the freeway and accelerated hard. Unlike last times, it was not severe and hesitation was there for very less amount of time. Smoke was also less compared to last times before repairs.

Till now I have changed following:
1. VCG
2. Spark plugs and coil
3. DV
4. PCV, breather tube and hoses.
5. Cleared oil from intercooler(almost 1/2 quart)
6. Cleaned the MAF

I am thinking of logging the data using torque pro app. I believe following parameters are important:
1. MAF air flow rate
2. short and long term fuel trim
3. RPM
4. Speed
5. Boost and vacuum
6. MAP
7. O2 sensor

Anything else I should include to diagnose the problem? Is the severity of the problem is related to the amount of oil in intercooler?

**KJack** · 06-10-2016 10:02 AM

I'm still thinking it's a cracked valve cover. Have you checked the underside for cracks?

**hemantpd1** · 06-12-2016 11:28 AM

Originally Posted by KJack

I'm still thinking it's a cracked valve cover. Have you checked the underside for cracks?

Checked the VC yesterday. When I blow air from PCV end while blocking the rear PCV port, I see bubbles coming out of VC passage. It seems I need to change it. Will update the thread once I change the VC. Thanks KJack!

**Deebes** · 06-12-2016 12:41 PM

This is exactly what my car is doing, I can't find anything to fix it. I hope you figure it out because I can not.

**Caconway2322** · 06-12-2016 02:00 PM

I'd check the compression and make sure the rings aren't sealing. It's easy to check. It will cause large amounts of smoke and rough eng conditions.

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**Caconway2322** · 06-12-2016 02:03 PM

It may be worst case but it's good to start their so you can x it out be for you just throwing parts at it.

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**hemantpd1** · 06-12-2016 07:49 PM

Originally Posted by Caconway2322

It may be worst case but it's good to start their so you can x it out be for you just throwing parts at it.

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First thing I did was compression test. Compression seems good.

Cylinder 1: 175
Cylinder 2: 185
Cylinder 3: 185
Cylinder 4: 185

**Caconway2322** · 06-13-2016 04:36 AM

Cylinder 1 seems too far away. Put about a tablespoon of oil in the cylinder to help seal the rings then recheck. If compression goes up then you have bad rings.

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**Caconway2322** · 06-13-2016 04:49 AM

It's still not horrible. But def a bit low. Next I'd say Find a way to hook up an air line to the intake Home Depot sells expanding rubber plugs in the plumbing aisle. Block off intake at air filter and apply pressure and check for leaks in CAC system.

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