Mobil1 15w50 experiment

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Oct 5, 2022
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Gonna do a long term experiment on mobile1 15w50. Temp range where I live goes from -10f to 100f. Gonna use 2 vehicles. A 2001 k1500 4.8l automatic. 205k on it. No cats. No egr. No knock detector. Known cam lobe wear. I forget which one but it was for cyl 7 or 8. Absolute beater of a truck. Was running t6 5w40. 1st impressions of the 15w50 is engine is quieter. But feels more sluggish. According to the horrible gm guages oil pressure has risen about 5 to 10 psi. Idles at 40 to 50. 60+ running down the road. Also about a 5deg rise in engine temp. Running about 180 on a 160 thermostat. 2nd vehicle is a 2008 Toyota yaris 1.5 automatic. 195k miles no catalytics. Was the wife's car and has been abused. Haven't driven that yet since the change from t6 5w40. Wife currently drives a 2011 nissan cube. But I'm not brave enough to switch that from t6 to 15w50 with it being our nice car and with winter coming. Learned alot on bitog and enjoy reading people's posts
 

Imowgrass

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Oct 5, 2022
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That is the experiment. How a 15w50 will do in harsh winter. In 2 different engine types. 1 being a pushrod ls v8 and the other a inline 4 ohc with vvt. The other reason I posted this is because I could find no posts about this particular oil run for a harsh winter in engines that call for 5w30. I may find out that it's a bad idea or it might be fine. But either way I will be able to share real world experince
 
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Not sure what could be determined from this...you admit one is a beater, the other abused....so say the engines develop severe wear, perhaps surmising from cold start wear...but how could you possibly know for certain if the engines may just as well near end of life and it's just, well, their time? :)
 

Imowgrass

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I guess I'm curios to see what happens. My bet is that both will be fine even in winter. I'm also curious if a 50w will affect the toyota vvt. Which I just replaced less than 1k ago. So if it gets vvt stumbling or codes again. Then I know that it's oil related and that a 50w would be to much for this car. The truck already has pretty bad cam lobe wear on cyl7 or8 I forget. So I don't have much to lose on it if 50w doesn't protect well. And if it goes another 50 or 100k then I'll know that the 15w50 is darn good oil.
 
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Don't see what the amount of cylinders has to do with it? I run M1 5w50 in our Land Rover Defender 300TDi and Rover Mini 1.3i?
Years ago I tried Pennzoil yellow bottle 20W50 in my girlfriend’s old 4 cylinder leaker Probe, and it made that car have no low end acceleration. Oil viscosity will affect a tiny high strung 4 cylinder a lot more than a low end rpm torque monster V8.
 
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Years ago I tried Pennzoil yellow bottle 20W50 in my girlfriend’s old 4 cylinder leaker Probe, and it made that car have no low end acceleration. Oil viscosity will affect a tiny high strung 4 cylinder a lot more than a low end rpm torque monster V8.

I've gone from *w20 oils to high HTHS ACEA A3/B4 or C3 oils in quite a few cars and never noticed a scrap of difference.
 
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That oil is too thick. Thermostat too cold. Period.

And I thought I was out on a limb running 10W30 in a Ford :)

Do you have the funds to replace the cam? Isn't this a LS based Vortec engine with a roller cam how did it get wiped? HOW does it have a "known" cam issue?

Also why do your cars have no cat cons?

I might recommend you quit playing games with way too thick thick oil on your cars.
 
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Will be following this post with interest as I run M1 15-W50 in my air-cooled two-cylinder 2013 Triumph Thruxton. Admittedly, I don't ride when temps drop much below 50F, but mostly in 70s/80s during the summer. The motorcycle has a wet clutch so the engine shares the oil with the trans - more demanding. Technically NOT JASO compliant per manu. spec. but many have recommended M1 15-W50 for this bike. Typically, I change my oil/filter about every 5.000 miles.
 
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Will be following this post with interest as I run M1 15-W50 in my air-cooled two-cylinder 2013 Triumph Thruxton. Admittedly, I don't ride when temps drop much below 50F, but mostly in 70s/80s during the summer. The motorcycle has a wet clutch so the engine shares the oil with the trans - more demanding. Technically NOT JASO compliant per manu. spec. but many have recommended M1 15-W50 for this bike. Typically, I change my oil/filter about every 5.000 miles.
You have an entirely different application, so the OP's experience in running a way incorrect lubricant for his engines doesn't apply to you. This M1 product would be more appropriate for an air cooled twin as long as the transmission enjoys it as well - if it is a shared sheared sump.
 
Joined
Dec 26, 2005
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One should not use an oil with a 15W winter rating in a “harsh winter”. Use an oil with an appropriate rating.

And if you have a material or design defect then no grade is going to fix it. A European 30-grade with an HT/HS of 3.5 is adequate for nearly any commercial stock engine. Anything above that is unnecessary. It won’t harm but it won’t provide any real benefit.
 
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on the road in NE Oklahoma
Thermostat is too cold . Should be using a 180 series at a minimum. Using a 160 will just make your engine take longer to reach optimal temperature, leading to moisture in the oil that never gets burned off.

As far as using the Mobil 1 15w-50 goes as an experiment, that’s very old news. The results have been in for decades.

Hundreds if not thousands of vintage car owners have been using it for at least 20+ years, myself included, in all types of temperatures. In seldom used cars, and in daily drivers. My daily driver vintage Mustangs and Shelby’s never had issues starting or driving with the 15w-50 in temperatures ranging from zero F to 120 F. Excellent wear protection .

But I do agree with others here, that Mobil 1 0w-40 is a better all season choice. Much less drag and with all the wear protection of the 15w-50. Surprisingly, I found that both oils, when hot, gave identical oil pressure and temperature.,

Z
 
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