# Gas smell in oil???



## majorahole (Sep 17, 2009)

checked my oil last night, cause i had to add some to my wife's jetaa 2.5 and i figured i havent checked my oil since i bought the car about 2 months ago, and i noticed it smelled different than the normal oil smell. it took me a second but i figured out it was fuel. some google searching tells me that can just happen aparently?, is there anything else that could cause it?? 
i was thinkin PCV??

any opinions??


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## Krieger (May 5, 2009)

its pretty normal for our engines, that's one of the reasons why we change our oil every 3-4k miles.

if it ever becomes much more than usual, you could be looking at a leaky seal in your HPFP or the like.


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## majorahole (Sep 17, 2009)

thanks, im suprised i never heard about that before. kinda seems like a design flaw, id like to stop this if i could, just because it happens to everyone doesnt mean its right.


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## jmj (Feb 6, 2001)

You may want to spring for a Used Oil Analysis to see how much fuel dilution you're getting.


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## skier45 (Jul 27, 2009)

*oil smell*

one of the supliers they use is fuchs, there oil smell like the divil. i use their titan 5w-40 with great success. smell like h*** though. i can't smell your oil so i don't know.


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## majorahole (Sep 17, 2009)

jmj said:


> You may want to spring for a Used Oil Analysis to see how much fuel dilution you're getting.


where can i have that done?? dealership?


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## jmj (Feb 6, 2001)

This is the one I use: http://www.blackstone-labs.com/


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## EosDistress (Dec 11, 2010)

*Oil analysis after smelling gasoline.*

To the poster whose oil smelled of gasoline; did you ever do the oil analysis to check for gas contamination? 

I have a 2008 Eos 2.0T with 18,000 miles. After 1,700 miles oil has no lubrication to the touch and smells of gasoline. An oil analysis done at this interval revealed that crankcase is now 3.5% fuel (2% is not good and that is after 5,000+ miles). At 3.5% the viscosity has broken-down beyond acceptable limits. VW Techs (Manufacturer) say they’ve never “heard” of an oil analysis so they have nothing against which to compare (?) and since there is no “error code” they feel there is nothing wrong. 

Has anyone done an oil analysis on his or her car? What levels of fuel have you found? What levels of viscosity breakdown? Any help would be appreciated.


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## bificus99 (Aug 2, 2008)

LOL never heard of an oil analysis. The crap some dealers say.


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## HalvieCuw (Mar 20, 2003)

bificus99 said:


> LOL never heard of an oil analysis. The crap some dealers say.


 ....you have been here since 08 and haven't seen threads on blackstone oil analysis...


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## vliou (Nov 22, 2009)

3.5% is way out of wack. I've had 2 oil analyses done. I use GC and the first oil analyses had 2.0% fuel dilution and the oil sheared way down after 2700km. It didn't turn out to be rings, but I had used fuel injector cleaner and the one I used (Redline SI1) caused it to end up lowering the flashpoint (another member had the same issue). 

http://i140.photobucket.com/albums/r34/saaber1/oil.png 

I later redid a sample and didn't have an issue 
http://www.imagebam.com/image/b16b1096780116 

Thing to also remember: cold winter drives where your car doesn't get fully up to temp contributes to fuel dilution. Our cars also run rich and don't enter FSI (Fuel Stratified Injection). Therefore, no ultra lean burn. B/c our car runs rich - it also tends to promote fuel dilution. 

Is it a problem? No, not unless you do frequent short, cold weather driving


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## saaber2 (Jul 15, 2008)

vliou said:


> Is it a problem? No, not unless you do frequent short, cold weather driving


 Agree with vliou that fuel injector cleaner can give false impression of too much fuel dilution in some cases. But I have to respectfully disagree that it is not a problem. In some ways you could say it plays a major role in many/most of the "problems" we see in this engine. I've been fortunate to talk to some of the brightest oil formulators out there who have studied oils for many years and here is what is going on as I understand it. 

3 types of fuel get past the rings, (1) raw fuel which doesn't do that much relative harm (but may contribute to valve deposits some), (2) reacted fuel, which just goes out the pcv system and doesn't do that much harm (but may contribute to valve deposits some), and (3) partially reacted fuel, which is the type that does all the harm to the oil. It is extremely reactive and creates cross linkages with the oil, contributes to varnish, deposit precursers, etc. Basically it raises holy H$ll with the oil. 

Of course as the oil breaks down (especially the anti-oxidant additives), wear potentially increases, but beyond that there are a lot of other problems. These highly reactive and highly polar precursers are strongly attracted to metal, especially hot metal. So ring deposits, injector deposits, valve deposits, increased wear are all heavily influenced by fuel dilution. 

In relation to the valve deposits, the literature is showing that oils which break down in the presence of fuel dilution create more valve deposits (which of course is logical). (Isa, et al) 










The literature also shows that running the oil too long increases deposits. This is also logical if we think about how the supply of this partially reacted fuel to the oil continues over time, continuing to degrade the oil and making new aggressively reactive compounds. These are the likely primary sources of our valve deposits IMO.


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## crew219 (Oct 18, 2000)

@Saaber, is that from the Lubrizol white paper about the effectiveness of ester-based oils in reducing intake valve deposits on direct injection engines?


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## vliou (Nov 22, 2009)

And just when I think I've read enough on the net about fuel dilution, I learn something new from Saaber2. Awesome post!


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## saaber2 (Jul 15, 2008)

The graph and text pic are from some researchers in Malaysia (Isa and Haji-Sulaiman). They tested valve deposit buildup using different oils and service intervals. They also evaluated different blends of gasoline and also different gas blends doped with used oil. Basically the blend of gas had little effect but the oil had a large effect. 

The 3 types of fuel explanation are from an oil formulator who I don't have permission to name. This guy is amazing and can tell you the specific molecule that breaks down and what it cross links with in the oil to form the deposit precurser. 

Both sources indicate that the anti-oxidant ability of the oil is very important. The Isa paper says that simply looking at TBN/TAN, which is often used to indicate how much "life" is left in the oil, is not an accurate indicator of how much the oil is degraded. I've seen this a lot where people say "the TBN is still good so you can run it longer" when all the other indicators show otherwise. Isa identified another study which also showed that deposits are greater from oil run a long time (shown below). 

All of this seems to support what seems to be fairly obvious: Oils are "under attack" from fuel during operation over time. The fuel (the partially-reacted fuel especially) breaks down the oil over time, making/releasing compounds that can be evacuated through the PCV system whereby they reach the valves and can contribute to deposits. I would also throw in here evacuation through the PCV system the broken "relatively unstable" viscosity modifiers which can be the first components to "shear". Oils that can "resist the attack" better (better oxidative stability such as due to type/quality of anti-oxidants) form fewer deposits.


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## bificus99 (Aug 2, 2008)

HalvieCuw said:


> ....you have been here since 08 and haven't seen threads on blackstone oil analysis...


 Undoubtedly you need reading comprehension skills. 
I was commenting on the tech at the OPs dealership.


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## DubbinDubCee (Nov 3, 2009)

Could weak and underrated spark plugs contribute to a problem like this? Such as in a situation like chipped car driving for an extended period with copper plugs?


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## rhouse181 (Apr 13, 2008)

saaber2 said:


> The graph and text pic are from some researchers in Malaysia (Isa and Haji-Sulaiman). They tested valve deposit buildup using different oils and service intervals. They also evaluated different blends of gasoline and also different gas blends doped with used oil. Basically the blend of gas had little effect but the oil had a large effect.


 Saaber, did you find this research on BITOG... or someplace else on the web? Looks like it would be an interesting read. This is essentially what we have been trying to experiment with, but in a more "scientifically controlled" environment that all the naysayers bitch about never achieving in real world testing. 












I read this an immediately thought Mobil 1 0w40...


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## saaber2 (Jul 15, 2008)

Rhouse, I've been trying to track down the Nomura paper, but I can't find it.


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