Gas Smell in Oil...Need Your Help.

[europaisch]

I drive a 2008 2.0T Avant tiptronic.

The day after I had my car serviced for its 25,000 mile interval I had to drive to Las Vegas for work. (9 hour drive) It seemed to be idling a little rough and sluggish in power. I attributed the symptoms to the staggering 100+ heat that Vegas offers in the summer months.

After returning home in SF the rough idle never went away but the 'zippiness' of the motor seemed to return. Recently, the car has started chugging upon starting. It compensates by elevating the revs and eventually the car returns to it's rough idle.

Another recent development within the last week: When driving if I have to stop quickly or normally, the motor and power seem to drop out right at the end of the braking. Then the motor/tranny coughs and brings the car back to it's rough idle. (An easy way of explaining this would be like: Coming to a stop sign in a Manual transmission and using only your brake to slow for the sign and not pushing in the clutch. You know how the car/tranny starts to chatter? That's what mine is doing.)

Tonight I popped the hood to find oil leaked and splattered out of my oil cap on the motor. My first thought is too much oil. I check the oil, it seems a bit high. But the more alarming discovery is that the oil really smells of gasoline. This can't be right, I've never experienced that before.

Thoughts, feelings, concerns, diagnoses?

Thank you in advance.

[CBRmatt600]

PCV. Replace it.

[europaisch]

Also: I'm not getting a Check Engine Light.

The common problems thread does not mention if a bad PCV throws a code/warning.

[CBRmatt600]

It spews oil around the cap, and that is the only thing I know of that does.

[mttst]

PCV valve, genius. You have too much crankcase pressure.

[UGwagen]

PCV check valve failed. When it fails, it allows the boosted intake air pressure to pressurize the the crankcase. That's why it exploded out of the oil filller cap. VW/Audi has gone through several revisions of this.

Smells like gas? Normal. The FSI system is prone to cause fuel dilution in the oil.

[boosted4life]

While we are on the subject of PCV, is there a DIY anywhere for replacing the PCV on a B7? I have searched and haven't found much.

[UGwagen]

While we are on the subject of PCV, is there a DIY anywhere for replacing the PCV on a B7? I have searched and haven't found much.

need torx screw driver. I forget what size to use.

remove the hoses from the pcv valve. remove the screws (Don't drop them). Reinstall is opposite of removal.

Pliers help with the hose removals

... it's pretty straight forward

[Rotond0000]

PCV doesnt throw a CEL. i had the problem twice and it showed up the first time temporarily and went away and the second time it didint at all

[scoobycarolan]

My 08 just flipped 20k and I put in the Eurojet PCV. breathing way better now. $70.

[europaisch]

Very cool. It sounds like the PCV is the problem. Thanks for the responses.

Couple of questions:
- Which PCV replacement is best? OEM updated? Eurojet? Other suggestions?
- It was asked before; any DIY write-up on replacing the part?
- Lastly, should I just try to get this covered under warranty as opposed to spending the money and time myself? Or will I end up with the same crappy product?

[RS4POWER]

PCV check valve failed. When it fails, it allows the boosted intake air pressure to pressurize the the crankcase. That's why it exploded out of the oil filller cap. VW/Audi has gone through several revisions of this.

Smells like gas? Normal. The FSI system is prone to cause fuel dilution in the oil.

You are correct. Oil that smells like gas is from fuel dilution. This is common on the FSI motors but it should not be disregarded. The more fuel dilution the more the oil loses its lubricating properties and its flash point drops substantially. That is the point where FSI motors have seen an accelerated rate of carbon build up.
Every time you catch your oil smelling like gas you should change the oils immediately. That might mean even as little as 2k miles on the particular oil.

OP- How many miles are on your car and which oil are you using?

[europaisch]

28K for the miles. And I can't remember what they put in the last time I was at the dealership. I'm almost due for an oil change as it is anyway.

[darmz]

I am not quite sure what it is, but whenever i fill up the gas tank(full tank) my car smells like a gas station. My car is due for an oil change @64K, is this the PCV problem as well? I do have a CEL on but it came on like 2months after i could smell the gas inside.

[diagnosticator]

It is completely normal for the oil to have a gassy smell from unburned fuel blow-by past the piston rings. If you are concerned that the fuel contamination is severe, get an oil sample and have it tested.

[europaisch]

Diagnosticator, look at that rep. Hot damn.

Thanks man. I'm a little less leery about the gas in oil smell now. Just gotta get that PCV replaced next week.

[RS4POWER]

There will be fuel dilution on any direct injection engine. Some oils can withstand fuel dilution better than others. The Audi approved oils on FSI engine do not do a good job of that and depending on driving habits can knock the oil out in 2k+miles. Once fuel gets in the oil its starts breaking down its lubricating properties and lowers flash point. As you can start to see this is not a small problem.

I have been through your symptoms in my RS4. I understand the engines do differ but the problem you have been reporting has haunted a lot of 2.0tfsi. Unburned fuel is a problem, if its not burnt its sitting on the back of your intake valves and joined with oil vapor which is the root cause of carbon build up on these FSI engines. Once carbon is built on the valves and top of the combustion chamber air flow is decreased and so is HP. The engine protects itself by retarding timing and the car feels substantially slower (sluggish) than when you first bought it. Rough cold starts and idling is also common when a car is built up with CB.

There is tons of info on this issue and feel free to PM if you care to know more.

At this point I would advise you to change oils as soon as you smell fuel in your oil and forget about changing the oils every 10k miles as prescribed.

[diagnosticator]

At this point I would advise you to change oils as soon as you smell fuel in your oil and forget about changing the oils every 10k miles as prescribed.

I agree with you on this, changing the oil is the only way to limit the amount of oil contamination from combustion residues, fuel dilution and wear particles, including harmful dirt inducted with the intake air. However, the engine oil will begin to smell from fuel dilution even before there is enough fuel in the oil to effect the suitability for continued use, but the amount of fuel dilution can quickly increase above the maximum dilution percentage depending on driving conditions. Shorter OCIs are particularly crucial for engines the are mostly driven in the city, that is considered Severe Duty on the engine oil, compared to mostly highway driving. The situation justifies changing the oil more frequently than the factory OCI requires. Audi states that severe duty use will require shorter OCI intervals, the 10K OCI is not suitable for a large number of cars that are driven in a manner consistent with severe duty on the engine oil. Stop and Go city driving being the most severe duty for the oil. Finally, the 10K OCI is not specified because it's the best OCI for the engine, the real reason is that it's best for Audi's bottom line and reduces the cost of warranty period maintenance expenses. Obtaining a couple of oil sample tests, will show how much fuel and other contamination is accumulating in the oil of each engine resulting from the unique driving conditions for each owner and the mileage and type of driving since last changed.

[Msu2312]

It spews oil around the cap, and that is the only thing I know of that does.

x2

[diagnosticator]

x2

Is that with the cap screwed on all the way? If that is the case, either the cap gasket requires replacement, or the crankcase pressure is very high, due to crankcase ventilation failure. IE, is plugged up tight.

[europaisch]

RS4 and Diagnosticator, since the topic is up, is there a particular oil that is more resistant to fuel dilution?

[RS4POWER]

RS4 and Diagnosticator, since the topic is up, is there a particular oil that is more resistant to fuel dilution?

I would advise you to do an oil analysis. I would recommend Terry Dyson as he is already familiar with FSI engines.

The only oil proven to combat fuel dilution in the RS4 FSI engine is the RLI 5w40. A lot of RS4 owners are running on this oil now even though it is not an AG approved oil. Since the results were so good A6 3.2 FSI guys have converted over and so have 2.0tfsi.

This oil was formulated based on extensive testing on the RS4. The RS4 motor is a bear on oils in a way that the 2.0T might not be. That is why I suggest/urge you to do analysis. Terry has analyzed 90% of Audi approved oils (for the RS4, not sure if 2.0T is the same) and would steer you in the right direction if an approved oil would work for your engine. If not there is RLI which I am running in my RS right now and I am very pleased with it.
Let me know if you need more info...

[diagnosticator]

RS4 and Diagnosticator, since the topic is up, is there a particular oil that is more resistant to fuel dilution?

Regarding fuel dilution alone, there is no particular oil more resistant to viscosity loss than any other oil's resistance against fuel dilution. In general principle, when fuel dilution rates are high, higher viscosity oil is used to offset the lost viscosity from the fuel dilution, together with oil analysis and frequent oil changes based on the test results. For each case, OCI is adjusted after deciding on the maximum fuel dilution permitted for the engine and operating conditions with consideration of the real world sensitivity that fuel dilution has for a certain engine design and exhibited for the unique driving conditions relevant for each case.

[europaisch]

Just following up for future seachers.

I had my PCV replaced at the dealership. Rough idle is gone. Stuttering start is gone as well.

I also had my oil changed for good measure. Car feels smooth and cool again.

Thanks for everyone's help.

For reference - PCV replacement:
06F-103-221-H VENTHOSE
06F-129-101-E VALVE (apparently this is the revised part/part #)

[diagnosticator]

Thanks for the solution update, this is the most important part of the thread!