Worst oil you've ever used?

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This goes back a ways. We had a truck that burned through oil like crazy, around a quart a week. We used Purelube SAE 30 which was the cheapest oil we could find. It came in a gallon white plastic jug and was stocked at the neighborhood Food King supermarket.
 
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Castrol Magnatec oxidized into a coal black corn dog on the dipstick with only 3k in a Pentastar …
5W20 that turned extremely viscous …
Was this your personal vehicle, or did you witness it? Seems hard to believe, when so many have had good UOAs with this oil in turbo engines.
 

4WD

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Was this your personal vehicle, or did you witness it? Seems hard to believe, when so many have had good UOAs with this oil in turbo engines.
Car I bought new … near 50k miles … was doing gear oil … decided to check oil level.
After seeing dipstick … flipped over the fill cap and not pretty …
Had some QSUD and put that in. Car mostly ran M1 or PG …
 

cwilliamsws6

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How do you know the Q stuff was the worst oil you've ever tried? Anything quantitative?
It's the only oil I've used that has a consumer alert from PQIA out for it, any other time after that I've used trusted name brands or dealer bulk.
 
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Worst oil I ever used has to be the 10w-40 I used back from 1970 to whenever manufacturers declared 5w-30 was the oil to used in cars. By the end of the 1990s there was almost no similarity between a good dino oil and an oil from the 60s and 70s. However, I always used what I judged to be the best oil available at a reasonable price. Way back I thought that was Quaker State or Penzoil although I used a lot of Sears oil over the years. Now, I think it is Mobil 1 on sale.

Quote:
"As a teenager I worked at a gas station that we kept all the used bottles of oil sold to customer's. We flipped them up and drained them into a gallon jug. This oil was then put in a used 1 quart container and given away to customers that needed oil but couldn't afford it. I guess this was my first experience with 'frankenbrew.'"

I think that was an excellent idea for those in real need. When I first started driving oil still came in cans and you had to have a way to open them, an oil spout was best. I cannot even remember when it switched to plastic bottles. It was a vast improvement since you did not have to leave a partial quart open.
 
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I have no idea which is the “worst” oil. But there are a couple oils I dislike. I don’t like Pennzoil PurePlus oils, towards the end of an OCI I always experience oil consumption. For ex: a 5K OCI, the first 4K miles there is no consumption, then from 4K-5K it just starts disappearing. Don’t know why. Multiple vehicles.

I also dislike Kendall GT-1 Max Synthetic. I had high hopes for this one. When draining the oil after an OCI, it reeked of a smell similar to tar. Not very confidence inspiring.

Never really disliked any other oils.
 
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Car I bought new … near 50k miles … was doing gear oil … decided to check oil level.
After seeing dipstick … flipped over the fill cap and not pretty …
Had some QSUD and put that in. Car mostly ran M1 or PG …
I’m sure not doubting what you saw, I just have a hard time believing Magnatec would do this. Any way you could’ve bought a jug of used oil or whatever that some scumbag had returned to the store?
 

4WD

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I’m sure not doubting what you saw, I just have a hard time believing Magnatec would do this. Any way you could’ve bought a jug of used oil or whatever that some scumbag had returned to the store?
Never had any containers look tampered with - all oil looked clean. I always figured ”synthetic“ under $20 a jug have a slug of Grp2+ … but should go 5k-10k without issues … All other oil changes were 5k … Even did a 5k with STP made by Amalie … good run … That car did short trip quite a bit …
 
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I somehow learned at a young age how to read an oil bottle. Plus I bought oil at auto parts stores and didn't see any real junk. I do have some "SA" oil for my tractors oil bath air filter if that counts. I would not use it in the engine. It currently has Castrol 20w-50 that is "SG" rated. Much higher rating than what was around in 1956.
 
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Dollar General branded oil. SA rated, with a note not to be used in engines built after a certain year(1950 maybe?). Cusps to them for properly labeling the oil. It went into the oil bath air cleaner on my 600 Ford tractor.
That's what my uncle uses in his air compressor.
 

SR5

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Not that that bad and not myself, but I was at a fuel station recently and a guy in a nice suit was pouring in 1L of generic oil into his new Audi A4. He must have had an oil light showing.

It was a United station, and it was their own brand of oil, in a plain blue container. It was a 15W-40 conventional rated only API SL/CF. Not exactly VW / Audi spec, and well overpriced for what it was.

I looked into it, and the stuff was made by Valvoline, so at least you could trust it did meet SL. It’s probably repackaged XLD 15W-40 for those in Australia, which you can pick up on sale for as low as $2 per Litre.

At any auto store, for less money you could have purchased a better 15W-40 that was ACEA A3/B3 and SN/CF, or spent a little more to get VW 504/507 synthetic. Still better 15W40 conventional than driving to work each day on low oil.
 
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None of my oil choices ever failed on me.. I wouldn’t say “worst” but maybe cheapest. I’ve ran wolfshead and peak in previous autos of mine.
 
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Chrysler 300 with the 2.7 got this
1629805457674.jpeg


2008 Hyundai Sonata with the 2.4 got this
1629805581252.jpeg
 
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How about Dollar General motor oil? I would not even use that in my lawn mower, but i have clients that do, for throw away wal-mart lawnmowers, and the engines dont explode... at least not instantly, but i would never even think of using something like this in a car. Its still SF, so maybe for an old V8 or something you could get away with it.... Temporary.....
 

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Worst oil? Everything I drained from my air cooled VWs some 30 years ago,
since these engines didn't have an oil filter and just 2.5 l (!!!) total capacity.
.
 
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Actually , the oil that I would never use again is NAPA 10-30 Synthetic . I put it in my V-8 Tundra and immediately noticed more engine noise . I assumed it was a quality oil but I definitely noticed the difference .
 
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