What gives used oil a foul smell?

[gedcruise]

Drain oil is usually noticeably darker than fresh oil, and sometimes has a strong smell. Now, oil from a diesel has a jet black look (at least out of one of the old 240Ds I had) and has a distinctive smell.
Oil drained from a gas car may smell rather foul. I drained PP 5W-30 from my '97 Accord after about 6K, back in March, and the oil really stunk. Why? It had been run in some really cold weather. Fuel dilution? You can bet that on a below zero F morning, that puppy ran in the driveway for a bit, with me in the house, before I set out to work.
What makes used oil stink?

 

[TallPaul]

I don't know, but you said it better in your message when you said "distinctive smell." Yes it is different, but I don't consider if foul, but rather pleasant. It brings back many fond memories of past oil changes.

 

[oilyriser]

The smell of engine exhaust direct from the cylinders is pretty bad, too.

 

[Sienna Driver]

could be fuel.

 

[Fester]

Last oci on the Jeep I used formula shell, it stunk in a freshly open qt. I figure if used oil dint smell, then it's just not doing the job.

 

[Pablo]

Pretty much anything with a good stink has S (sulfur) associated with it. S from the fuel, or S in the oil, or S additive (thio = sulfur-carbon) compounds breaking down.

 

[Merkava_4]

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I drained PP 5W-30 from my '97 Accord after about 6K, back in March, and the oil really stunk.

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PP has been the subject of many smell complaints on this board. Doesn't bother me though; gives me an excuse not to buy it.

 

[06VtecV6]

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Drain oil is usually noticeably darker than fresh oil, and sometimes has a strong smell. Now, oil from a diesel has a jet black look (at least out of one of the old 240Ds I had) and has a distinctive smell.
Oil drained from a gas car may smell rather foul. I drained PP 5W-30 from my '97 Accord after about 6K, back in March, and the oil really stunk. Why? It had been run in some really cold weather. Fuel dilution? You can bet that on a below zero F morning, that puppy ran in the driveway for a bit, with me in the house, before I set out to work.
What makes used oil stink?

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What gives used oil a foul smell, simply the same thing that gives humans a bad smell. Bad stuff inside however I do recall that MC had a pretty inhospitable smell when I cracked it open right before purchase. I also recall one instance of foul smell soon after but never again. Never stuck around when I drained that MC whether it had a foul smell because I paid someone else to do it.(GY Gemini) I guess I don't know what would give oil a foul smell *when* you drain it.

 

[Dr_No]

Pablo is on the right page, just basic elements from oil breaking down

 

[3putter]

All them rotted out Dinosaurs it's made out of.

 

[06VtecV6]

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Quote:

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I drained PP 5W-30 from my '97 Accord after about 6K, back in March, and the oil really stunk.

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PP has been the subject of many smell complaints on this board. Doesn't bother me though; gives me an excuse not to buy it.

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I tried it once, PP 5w-20 and wasn't overly impressed. However, their 0w-20 specs have me intrigued especially now that I have surpassed the warranty period by more then 'a few Hondo'..has anyone seen them recently..

 

[JAG]

Motor oil that's just been heated to high temps stinks too...obviously no fuel or combustion products were in it.

I always add a little rose oil to my motor oil so it never has that "not so fresh feeling". j/k

 

[Fester]

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Motor oil that's just been heated to high temps stinks too...obviously no fuel or combustion products were in it.

I always add a little rose oil to my motor oil so it never has that "not so fresh feeling". j/k

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LOL. Someone come up with an engine douche. Maybe they did "auto RX"

 

[Harley Anderson]

You need to smell rotella (AKA rosmella) right after an oil change on a hot day in a cummins with open crankcase breather. Most people think you spilled half a gallon on your exhaust.

 

[lovcom]

Don't get too close to the used oil. It's Car FECES! Yuk!

 

[wantin150]

I LOVE the smell of used motor oil. After changing it, I put the pan in the car so it makes the car smell like it. Am I the odd ball here?

 

[TallPaul]

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I LOVE the smell of used motor oil. After changing it, I put the pan in the car so it makes the car smell like it. Am I the odd ball here?

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Finally someone else who likes the smell of used motor oil. I am not alone after all.

 

[Max_Wander]

I prefer the smell of used diesel oil over gas oil. I mean, if i had to choose

Used gas oil can sometimes smell like burnign gas/polyester.. it really does smell carcinogenic, if carcinogens had a trademark smell. Used diesel oil smells more like plumbers putty (and old ships)

 

[Merkava_4]

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Used diesel oil smells more like plumbers putty. . .

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That's something I didn't expect to learn today.

 

[JohnBrowning]

I have often smelled a rancid smell like what you would smell from a grease trap that catch's food type grease.I usualy smell this with dino oil. I have only smelled that smell once with a synthetic.