Mobile 1 Classic oil??

-

johnboy73

Member
Joined
Jun 5, 2025
Messages
6
Reaction score
3
Location
sevierville
318 fresh build in 74 duster. drove / ran perfect. changed from the break in oil to Mobile 1 classic , drove 5-6 miles and car overheated.
started rattling , immediately pulled over and had towed home. Dug into motor and now bearings have ware but the oil is thinner than any oil I have ever seen and the smell is like a chemical horrid smell. Not just a burnt smell from running hot. Crank needs repolished rod and main bearings need replaced. has anyone experienced this? the car ran perfect until the oil change.
 
318 fresh build in 74 duster. drove / ran perfect. changed from the break in oil to Mobile 1 classic , drove 5-6 miles and car overheated.
started rattling , immediately pulled over and had towed home. Dug into motor and now bearings have ware but the oil is thinner than any oil I have ever seen and the smell is like a chemical horrid smell. Not just a burnt smell from running hot. Crank needs repolished rod and main bearings need replaced. has anyone experienced this? the car ran perfect until the oil change.
What did your oil pressure gauge tell you? What filter did you use?
 
Excessively rich carburetor (likely damaged or other failure in the carb) will dilute the oil and destroy the engine. Pictures of damage? Is the hatch gone in the cylinder walls.

The known issue with Mobile 1 was the Synthetic version. Many Subaru engine (WRX) lost their rod bearings to that stuff.
 
Excessively rich carburetor (likely damaged or other failure in the carb) will dilute the oil and destroy the engine. Pictures of damage? Is the hatch gone in the cylinder walls.

The known issue with Mobile 1 was the Synthetic version. Many Subaru engine (WRX) lost their rod bearings to that stuff.
Highly possible on the rich carburetor, I didn't find anything on the Subaru bearing issue, not that it didn't happen, just that nobody posted anything about it
 
Many unanswered questions. If the bearings were damaged in a short time either the clearances were wrong or the oil was contaminated with fuel or antifreeze. No mention of the oil being over filled. I would capture some of the horridly spelling oil and have it tested. You can fix the damage but not fix the cause.
 
What weight of oil were you using? It would seem that that would be relevant. Mobil1 15W50 contains ZDDP for flat tappet engines. Other weights do not. But your symptoms really sound like contamination, probably by fuel.
 
I tried Mobil One when it first came out. Took the 273 out and wrung it out for about 10 miles. Didn't like the hot oil pressure, drained it out and put Valvoline Racing straight 30 back in and dumped the Mobile One. Never looked back.
 
What weight of oil were you using? It would seem that that would be relevant. Mobil1 15W50 contains ZDDP for flat tappet engines. Other weights do not. But your symptoms really sound like contamination, probably by fuel.
Wasn’t fuel. No fuel smell to the oil but I can’t describe the smell well. Maybe more like gear oil than motor oil. I used 10/30 mobile 1 classic for motors 51 to 96. First time I’ve ever seen it.
 
What weight of oil were you using? It would seem that that would be relevant. Mobil1 15W50 contains ZDDP for flat tappet engines. Other weights do not. But your symptoms really sound like contamination, probably by fuel.
Mobile 1 classic 10w30 has ZDDP in it as well according to their website
 
Excessively rich carburetor (likely damaged or other failure in the carb) will dilute the oil and destroy the engine. Pictures of damage? Is the hatch gone in the cylinder walls.

The known issue with Mobile 1 was the Synthetic version. Many Subaru engine (WRX) lost their rod bearings to that stuff.
I’ve run mobile one synthetic in all my modern engines and never had any problem. My drive to work and back Camry has 220,000 miles on it and has always run mobile 1. Not sure where you’re getting your information but mobile one synthetic is a great oil.
 
Mobile 1 synthetic oil is pretty great I've used it forever in my slightly newer vehicles. I wouldn't hesitate using any mobile 1 products. I do use valvoline VR1 in my old Mopars which I drive quite often.
IMG_2598.jpeg
 
There's a recent video by the motor oil guy on YT (Lake Speed Jr.). He found that modern motor oils have anti-wear compounds that work the same or even better than the zddp everyone harps on. "Classic" oils would have been good to have back in the 90s-early 2000s but now are kinda redundant. Just my $2.00 (adjusted for inflation).
 
See post #10.
doh.gif

Thanks Rusty :)
Personally, Ive always gone at least a good five or six hundred miles before switching over to synthetic, but thats just me.
Like @toolmanmike said, there are places that you can send your oil to and get it analyzed to dig into it further, perhaps find out what that horrid chemical smell is and if it was the oil itself that was contaminated.
 
Last edited:
I’ve run mobile one synthetic in all my modern engines and never had any problem. My drive to work and back Camry has 220,000 miles on it and has always run mobile 1. Not sure where you’re getting your information but mobile one synthetic is a great oil.

If it's working for you, great.
 

Mobile 1 synthetic oil is pretty great I've used it forever in my slightly newer vehicles. I wouldn't hesitate using any mobile 1 products. I do use valvoline VR1 in my old Mopars which I drive quite often.
View attachment 1716444681

Is there any oil you can buy off the shelf these days that's actually "bad"? I don't think so... Except allegedly what the OP has tried...?
 
The only bad thing I've found about synthetics, is if there is ANY possibility of an oil leak.....it'll leak. I started using it in my sportbikes in the 80's.
My new GSXR1100, picked up 3 mph top-end. Same road, same weather, etc....
 
What weight of oil were you using? It would seem that that would be relevant. Mobil1 15W50 contains ZDDP for flat tappet engines. Other weights do not. But your symptoms really sound like contamination, probably by fuel.
M1 Classic has the same add pack as M1 15w50 check out Lake Speed jr. the motor oil geek on you tube.
 
-
Back
Top Bottom