New motor oil smells just like gear lube, wtf?

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Zorba

Zorba

Lifer
Oct 22, 1999
15,613
11,254
136
So tonight I was doing an oil change on both of my cars, using Castrol GTX 5w-30. I've been using this for at least 5 years now with no issues. I had most of a 5 quart bottle left over from my last oil change, which did most of the first car except for about 1/4 of a quart.

So I open up the new 5 quart bottle and as soon as I pulled the seal, I was hit with the very strong smell of gear lube. I decided it was probably okay and I topped off the first car, just about a 1/4 quart. Then decided something just wasn't right, so I poured some into a cup it was dark in color much more like gear lube, than the normal amber color.

I've decided to not use it on the second car and go get a different brand. My question is, do you all think I should drain the oil out of the first car and put fresh in? I couldn't find anything on Google.
 
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3chordcharlie

3chordcharlie

Diamond Member
Mar 30, 2004
9,859
1
81
You need to find out what it is - I would imagine gear lube isn't intended for the kind of temperatures motor oil sees, and I have no idea if it would be stable.

For the minor cost I would drain and refill if you can't confirm what was in the bottle.
 
LTC8K6

LTC8K6

Lifer
Mar 10, 2004
28,520
1,575
126
If you are suspicious, it would be cheap insurance to just change it.
 
jlee

jlee

Lifer
Sep 12, 2001
48,518
223
106
It may be worth giving Castrol a call - they might give you a coupon for a replacement 5qt jug. :)
 
Zorba

Zorba

Lifer
Oct 22, 1999
15,613
11,254
136
I did try to give Castrol a call, but they were closed. I am going to call them again tomorrow.

I ended up draining and refilling the oil, not worth worrying about it forever for $20 in oil and 20 minutes of labor. I decided to give Valvoline a shot. I also poured about 1/2 a quart of fresh Valvoline in with the plug out to help flush any residual that may been left behind. Even though it was diluted 16:1, when I pulled the plug it still smelled strongly of gear oil.

It also did seem a little thicker when I poured it into the cup, but that could be my imagination.

I asked the guys at O'reilly's if they had ever had motor oil smell like gear oil and they had never heard of it.
 
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disappoint

disappoint

Lifer
Dec 7, 2009
10,132
382
126
Sounds like someone changed their oil then poured the used motor oil back in the container and returned it. Although they are supposed to have a seal. Was the seal intact when you opened it?
 
Zorba

Zorba

Lifer
Oct 22, 1999
15,613
11,254
136
disappoint said:
Sounds like someone changed their oil then poured the used motor oil back in the container and returned it. Although they are supposed to have a seal. Was the seal intact when you opened it?
Click to expand...

Yes, the 5-quart jugs have a foil seal under the cap, which I had to remove just like normal.
 
Kaervak

Kaervak

Diamond Member
Jul 18, 2001
8,460
2
81
The Walmart brand SuperTech stuff smells like gear oil. Surprised me a bit to say the least. Check over on BITOG and see if anyone else has had similar experiences.
 
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quakefiend420

quakefiend420

Lifer
Aug 26, 2004
14,685
1
76
disappoint said:
Sounds like someone changed their oil then poured the used motor oil back in the container and returned it. Although they are supposed to have a seal. Was the seal intact when you opened it?
Click to expand...

I've actually had that happen before, there were even sticks and leaves in the container :/

Best part was that Autozone didn't believe me and I had to throw a fit to get them to exchange the container for a new one.
 
pcgeek11

pcgeek11

Lifer
Jun 12, 2005
22,102
4,887
136
Throckmorton said:
I thought they were the same stuff. People put Mobil 1 5W-30 in their manual transmissions.
Click to expand...

My old 92 Usuzu Pickup takes 30 weight motor oil for the manual transmission. Some manual transmissions use automatic transmission fluid.
 
Zorba

Zorba

Lifer
Oct 22, 1999
15,613
11,254
136
If this was a new brand of oil for me I might not think it was that weird, but since I've been using it forever and it all of sudden drastically changed smell and color something just doesn't seem right.

LTC8K6 said:
I though he meant rear end gear lube...
Click to expand...

Yeah, I meant differential fluid, the 80w-90 or 80w-140 stuff that smells like hell, not ATF.
 
slugg

slugg

Diamond Member
Feb 17, 2002
4,723
80
91
Did you ever hear back from Castrol? I'm also wondering WTF is going on. I use Castrol GTX, too. I've never had this problem...

Where did you buy it? Walmart?
 
Zorba

Zorba

Lifer
Oct 22, 1999
15,613
11,254
136
Okay, I called Castrol back this morning. They immediately asked it was a 5W-30, which I confirmed. They told me there is a batch of 5W-30 GTX and MaxLife that was found to have a bad aroma and color, but they have tested it and it should be good. I wish they would've let their vendors know or posted info on their website, I contacted three vendors last night and searched all over their website.

I told her that I had tried to call them last night and they I searched for information on their website, but I ended up draining all of the oil and starting over. She told me they will send me some coupons for free oil for the inconvenience and cost. I am still going to try to take the oil back.

slugg: I did buy it at Wal-Mart, it is just so much cheaper there. I also generally don't worry about lower quality from Wally on items made to a specific specification.
 
SpatiallyAware

SpatiallyAware

Lifer
Sep 7, 2009
12,960
3
0
Didn't castrol get caught flubbing numbers and making false statements about GTX? Seems like mercedes or someone tested it and found it didn't meet whatever requirements were for the grade.
 
LTC8K6

LTC8K6

Lifer
Mar 10, 2004
28,520
1,575
126
Zorba said:
Okay, I called Castrol back this morning. They immediately asked it was a 5W-30, which I confirmed. They told me there is a batch of 5W-30 GTX and MaxLife that was found to have a bad aroma and color, but they have tested it and it should be good. I wish they would've let their vendors know or posted info on their website, I contacted three vendors last night and searched all over their website.

I told her that I had tried to call them last night and they I searched for information on their website, but I ended up draining all of the oil and starting over. She told me they will send me some coupons for free oil for the inconvenience and cost. I am still going to try to take the oil back.

slugg: I did buy it at Wal-Mart, it is just so much cheaper there. I also generally don't worry about lower quality from Wally on items made to a specific specification.
Click to expand...

Good nose you got there... :D

I would have changed it out too, even with the explanation.
 
slugg

slugg

Diamond Member
Feb 17, 2002
4,723
80
91
Zorba said:
slugg: I did buy it at Wal-Mart, it is just so much cheaper there. I also generally don't worry about lower quality from Wally on items made to a specific specification.
Click to expand...

Yea, I buy mine at Walmart too. Never had a problem before. I do avoid Fram filters for the Miata, though.

If you're getting a coupon for a free jug, head over to a parts store and pick it up there. Maybe that way, you'd probably be picking from a different "batch" that might be good. Explain your story and I bet they'd even let you open it in the store before you leave.
 
SpatiallyAware

SpatiallyAware

Lifer
Sep 7, 2009
12,960
3
0
It wouldn't be the first time wal-mart knowingly accepted lower quality goods at a discount. It also happens with tires.
 
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