Puff of blue smoke after coasting

[Estens]

Noticed today that my 2001 S6 gives a puff of blue smoke when I get on the accelerator after coasting down a hill.
I`m thinking valve stem seals or maybe piston rings.
Have searched the forum and internet in general but has failed to find some good info..

So my question is: Does these cars/engines have a history with bad seals/rings? or any other problem that can cause the blue smoke?

[NickyAsixx3sixx]

Most likely the valve seals.

To test it:
1. drive in 2nd gear, bring the rpms all the way up to redline
2. let off the gas, dont get out of 2nd gear
3. let it rev all the way down to like 2,000rpms
4. floor it
5. look for blue smoke out the back

[Scotty@Advanced]

Noticed today that my 2001 S6 gives a puff of blue smoke when I get on the accelerator after coasting down a hill.
I`m thinking valve stem seals or maybe piston rings.
Have searched the forum and internet in general but has failed to find some good info..

So my question is: Does these cars/engines have a history with bad seals/rings? or any other problem that can cause the blue smoke?

How many KMS are on that car?

Needing valve stem seals are not common but they do wear out from time to time.

Blue smoke can also mean rings, which would show up in a leak down test.

[Estens]

Most likely the valve seals.

To test it:
1. drive in 2nd gear, bring the rpms all the way up to redline
2. let off the gas, dont get out of 2nd gear
3. let it rev all the way down to like 2,000rpms
4. floor it
5. look for blue smoke out the back

Will test tomorrow

How many KMS are on that car?

Needing valve stem seals are not common but they do wear out from time to time.

Blue smoke can also mean rings, which would show up in a leak down test.

Car has done 134.000km, will stop by the local garage monday to see if they can do a leak down test for me.

[alterdcreations]

check the pcv system. Seafoam can free up stuck piston rings and restore compression.

[Estens]

check the pcv system. Seafoam can free up stuck piston rings and restore compression.

I`ll check the pcv system aswell. Not that crazy about additives, and it`s not sold in Norway.
But I guess its the part that goes in the inntake that can free up the piston rings and that water can be used the same way, might be worth a shot if the leak down test says my ring are bad.

[Estens]

Most likely the valve seals.

To test it:
1. drive in 2nd gear, bring the rpms all the way up to redline
2. let off the gas, dont get out of 2nd gear
3. let it rev all the way down to like 2,000rpms
4. floor it
5. look for blue smoke out the back

Did this today with a friend following me, he says there are small amounts of smoke comming out the back when doing this.
We also tried down a hill, and small amounts of smoke came out while coasting and at the bottom of the hill when I hit the accelerator a puff of smoke comes out. He says smoke is comming out of both tail pipes, I have a slight modified exhaust and if I remember correct left and right side is not conected.

[CALL AAA]

Do me a favor, just to rule it out. check your oil level and make sure you don't have too much oil.
That happened to a friend...of another guy...ok, fine. It was me.

[Estens]

Do me a favor, just to rule it out. check your oil level and make sure you don't have too much oil.
That happened to a friend...of another guy...ok, fine. It was me.

Checked the oil level earlier today, it`s about 2 dl. from max level (bottom of top red plastic)
Changed oil and filter 3000km ago so it must have just started burning oil or its burning very little oil

Hope your friends. oh I mean your engine didn`t tak any damage

[NickyAsixx3sixx]

The test I showed you to do will reveal bad valve seals.

Your friend saw the puff of smoke. This was caused by the valve seals letting the oil past them. So it's looking like you need new seals.

I had a V8 S4 which are notorious for this. It smoked for 40k miles until I sold it. Ran fine otherwise. Just keep the oil level correct...and think of it like you are constantly adding new oil. Never have to do an oil change ever again hahaha.

Maybe a filter here and there

Sent from my SCH-I535 using Tapatalk 2

[Estens]

The test I showed you to do will reveal bad valve seals.

Your friend saw the puff of smoke. This was caused by the valve seals letting the oil past them. So it's looking like you need new seals.

I had a V8 S4 which are notorious for this. It smoked for 40k miles until I sold it. Ran fine otherwise. Just keep the oil level correct...and think of it like you are constantly adding new oil. Never have to do an oil change ever again hahaha.

Maybe a filter here and there

Sent from my SCH-I535 using Tapatalk 2

I`m pretty shure it`s valve seals, but ordered a leakdown tester just to be shure.

Haha, not shure I want to do that. Planning on selling this car so I want everything to be OK ;)

If it turns out to bad valve seals, I guess I should replace rocker cover seals and cam shaft end cap seals at the same time. Anything else I should concider doing at the same time?
And i don`t have the time or tools to do this myself, so how many hours do you think it would take a mechanic with the right tools to do the job?

[NickyAsixx3sixx]

We are talking about the V8 4.2 right?

[Scotty@Advanced]

I`m pretty shure it`s valve seals, but ordered a leakdown tester just to be shure.

Haha, not shure I want to do that. Planning on selling this car so I want everything to be OK ;)

If it turns out to bad valve seals, I guess I should replace rocker cover seals and cam shaft end cap seals at the same time. Anything else I should concider doing at the same time?
And i don`t have the time or tools to do this myself, so how many hours do you think it would take a mechanic with the right tools to do the job?

If it's the valve seals then it's highly likely that the valve guides are worn out. Replacing the valve stem seals requires removal of one head, or removal of the entire engine, as the rocker shaft has to be removed and the car is on the way. If your guides are worn.. Then replacing the seals won't help much as they will leak shortly there after.

[Scotty@Advanced]

we are talking about the v8 4.2 right?

2001 s6 = 4.2 v8

[Estens]

yes

[Estens]

If it's the valve seals then it's highly likely that the valve guides are worn out. Replacing the valve stem seals requires removal of one head, or removal of the entire engine, as the rocker shaft has to be removed and the car is on the way. If your guides are worn.. Then replacing the seals won't help much as they will leak shortly there after.

So alot of work then :( so I`ll add head gaskets and valve guides.
Turing into a long shopping list

[Estens]

Since the leakdown tester wont be here until tomorrow I started checking the crank case ventilation. Started with the easiest part, the pcv valve.

Doesn`t seem to be a clog in the valve, so is it worth checking the parts of the system that are harder to get to?

Btw, the vlave looked like this.

[alterdcreations]

I would clean out that valve and all of the pcv hoses..it should help or at least be a start.

[Estens]

Not any better after cleaning valve and hoses, and to prepare for the leakdown test i pulled coils and plugs and discovered oil on the spark plug threads.

Will update as soon as I`m done with the leakdown test.

[Scotty@Advanced]

Not any better after cleaning valve and hoses, and to prepare for the leakdown test i pulled coils and plugs and discovered oil on the spark plug threads.

Will update as soon as I`m done with the leakdown test.

That could be valve cover gaskets. Also if your PCV system is plugged, that can blow oil past rings.

[Estens]

Can I turn the engine using a socket on the cam bolt? Or do I use the crank bolt?

[Scotty@Advanced]

Can I turn the engine using a socket on the cam bolt? Or do I use the crank bolt?

I'd use the crank bolt, the cam bolt diameters are pretty small, and you risk breaking the bolt.

[Estens]

You have been very helpfu Scotty, thank you very much :)

Done with the leakdown test now, biggest leak was 2psi. Since I used 80psi in, the worst cylinder has a 2.5% leak, thats OK right?
Pvc system is not clogged up, so I guess it`s valve stem seals then.

Pic of leakdown test gauges at the cylinder with biggest leak.

[alterdcreations]

That could be a stuck ring. Did you listen to the oil filler cap, air box or exhaust while you did the leak down test?

[Scotty@Advanced]

I'd address the pcv system first.. All that sludge could be the issue, when crankcase pressure increase, the additional pressure can blow oil/gas past the rings into the combustion chamber at the intake stroke. It would also register a good leak down test.

[Estens]

That could be a stuck ring. Did you listen to the oil filler cap, air box or exhaust while you did the leak down test?

I was under the impression that under 10% is good. The small amounts of air escaping went past the ring. But I belive this is normal

I'd address the pcv system first.. All that sludge could be the issue, when crankcase pressure increase, the additional pressure can blow oil/gas past the rings into the combustion chamber at the intake stroke. It would also register a good leak down test.

When I start the car with the pcv valve off the car, I can hear air rushing inn to the hose that connects to the valves underside.
And if I put my finger on it i I can feel the vacum.
When I put the valve back on without connecting the other hose, there is no vacum from where the hose from rocker cover connects to the valve. This tells me that valve is closing on high vacum in crankcase like it should and that hoses down to crankcase is not blocked.
Is this correct?

If I take the valve back of I can blow through it, so its not permanently shut.

So to me it seems like the pvc system is working like it should.

[Estens]

While waiting for parts I started stripping her down today. When I pulled the top of the intake manifold there was some oil inside of it.
Is this normal or is it because the pcv system might have been clogged up?


I don`t want to pull the heads and change the valve seals if I don`t have to, but I also don`t want to put her together again just to find out that cleaning the pcv system and intake manifold didn`t do anything.