Mobil 15w50 in 0w20 engine.

[Graham Piccinini]

My engine's oil cap recommendation states 0w20. I have been using Pennzoil 0w40 SRT for quite some time. Last oil change I switched to Mobil 1 15w50, just for S&G. I drive a lot and have a lot of idling time too. On average I go through 1 tank of gas per day. So if any changes take place - I notice them right away and can confirm if the change is permanent, or a one-time spike. Here are the results of Mobil1 15w50 in 2009 Scion xB: - Fuel economy did not take a hit over the past 7 tanks of gas, compared to the SRT 0w40. I was surprised, because I was under the impression that SRT 0w40 is a very "light" 40w and the 15w50 is a very "heavy" 50w. Expected an MPG drop, but that did not happen. - Really enjoying the smoothness of throttle response in the lower RPM range. Feels like the engine gained some torque. Can't explain why... Better ring seal?... BUT hate the slight HP loss in the upper RPM range. Very minor, but the loss is there. I will run this oil for 7k miles (my longest OCI yet in this vehicle) and will send it off for a UOA.

 

[TheKracken]

What are you trying to do here? Or did you just find a really good price?

 

[mightymousetech]

Back when I first started to drive, put 20W50 in my Civic (that called for 5W30) cause I drove the [censored] out of it, and someone said I should. Six months later spun a couple rod bearings.

 

[bubbatime]

Dont stop now!! SAE 60 and SAE70 are just right around the corner!!

 

[lexus114]

Originally Posted By: mightymousetech

Back when I first started to drive, put 20W50 in my Civic (that called for 5W30) cause I drove the [censored] out of it, and someone said I should. Six months later spun a couple rod bearings.

that might have happened anyway regardless of what weight oil was in there. the other reason could have been cold flow into the greatly needed areas when cold?

 

[aquariuscsm]

I'm a thick oil guy,but I think thin oils have their place,in 4cyl engines. The thickest I'd go is 5W30.

 

[userfriendly]

Thin oil in small engines and thick oil in big engines aquariuscsm? Sounds just like tired trucker... "10w30 in a 13 liter jerking 80,000 pounds on 10w30", implying that a Duramax should only need 0W16.

 

[FCD]

I run 20W-50 in an engine spec'd for 10W-40 with no issues, and it's a small 1124cc gas engine and i have not noticed any drop in fuel economy either.

 

[tig1]

In 1978 I put M1 5-20 in my Chevy engine calling for 10-40 when I lived in Maine. In cold temps(-5 to -20F) the lifters clattered awful on cold start with the 10-40. After the switch my engine ran smoother and all of the lifter clatter stopped, a little MPG was noticed, and I was able to increase my OCI to 10K without an issue.

 

[Graham Piccinini]

Originally Posted By: TheKracken

What are you trying to do here? Or did you just find a really good price?

I had a few quarts laying around from last year's Autozone clearance sale. My OPE have a lot of QuickSilver 25w40 stashed for it, so I decided to use the 15w50 in the DD.

Originally Posted By: mightymousetech

Back when I first started to drive, put 20W50 in my Civic (that called for 5W30) cause I drove the [censored] out of it, and someone said I should. Six months later spun a couple rod bearings.

What time of the year was it? It's gonna be above 70°F here for a while, will hit triple digits soon. So no cold starts to worry about. And the hot temps and frequent idling should keep the viscosity on the lower end.

Originally Posted By: bubbatime

Dont stop now!! SAE 60 and SAE70 are just right around the corner!!

If I get Castrol 10w60 for free or less than $2/qt - I'll dump it in without thinking twice about it. But that's about as viscous as I'll ever go...

Originally Posted By: aquariuscsm

I'm a thick oil guy,but I think thin oils have their place,in 4cyl engines. The thickest I'd go is 5W30.

I see what you mean, but at the same time most of Europe (slightly colder climate for the most part) runs on 10w40-20w50 in sub-2L engines until the cars rust out. And most, if not all, Mitsubishi Evo 4-cylinders run on 20w50. According to Evo forums that is... Yes, my engine is nothing like an Evo, but still fits in the 4-cyl topic.

 

[Dyusik]

I run 15w40, as thick as 10w50 before in a 1.0L 4 cylinder that revs up to 15.5k rpm, I'm sure my engine tighter than a plane Jane 4 banger designed to putt to the grocery store...

 

[andyd]

I would use 20w 50 in any car with a carburettor. 20w50 gives safety margins over a thinner oil. When a leaky radiator led to a hole detonating a hole in #4 piston, the rod bearing and journal were pristine. I attribute this to the 20w50 Castrol I was using in the Datsun 1.6 . I dropped to 10w 30 for winter.

 

[philipp10]

Originally Posted By: FordCapriDriver

I run 20W-50 in an engine spec'd for 10W-40 with no issues, and it's a small 1124cc gas engine and i have not noticed any drop in fuel economy either.

Guys...if there was a decrease in fuel economy it would be in the sub 1% range. I doubt your highly calibrated instruments (gas pump) would be accurate enough to notice...

 

[Graham Piccinini]

Originally Posted By: philipp10

Guys...if there was a decrease in fuel economy it would be in the sub 1% range. I doubt your highly calibrated instruments (gas pump) would be accurate enough to notice...

I once tried Valvoline 5w40 MST in my previous vehicle with 1zz-Fe engine. It felt like I was pulling a 5000 lbs trailer and my MPG decreased by 30-35% until next oil change. Needless to say it was a shorter OCI due to listed factors.

 

[aquariuscsm]

My reasoning,my gf had an old high mileage (200k+) Probe that used oil like it was going out of style. I tried 20W50 in it once and it made that slow car even slower haha. On the other side,my friend used 20W50 in his old 350 V8 Nova and you couldn't tell any difference.

 

[bigj_16]

I remember when my brother and I put Quaker State 50 weight racing oil in our 3 1/2 Briggs and Stratton go-kart engine in the 70's. It easily cut the horsepower in half

 

[53' Stude]

Originally Posted By: aquariuscsm

My reasoning,my gf had an old high mileage (200k+) Probe that used oil like it was going out of style. I tried 20W50 in it once and it made that slow car even slower haha. On the other side,my friend used 20W50 in his old 350 V8 Nova and you couldn't tell any difference.

You are a "thin oil" guy trying to "convert" :^) Try 5w20/0w20 in that 300Z :^)

 

[aquariuscsm]

Originally Posted By: car51

Originally Posted By: aquariuscsm

My reasoning,my gf had an old high mileage (200k+) Probe that used oil like it was going out of style. I tried 20W50 in it once and it made that slow car even slower haha. On the other side,my friend used 20W50 in his old 350 V8 Nova and you couldn't tell any difference.

You are a "thin oil" guy trying to "convert" :^) Try 5w20/0w20 in that 300Z :^)

Oh my goodness I'd never ever feed her those It was traumatizing enough pouring 10W30 in her haha.

 

[FCD]

In South America, Africa, South east Asia, they put Mineral 20W-50 into [censored] near anything with an internal combustion engine. In fact in Sotuh America you will find most high mileage oils are 25W-50 or even 25W-60 oils!, but in a tropical climate near the equator where there aren't 4 defined seasons it likely doesn't matter that much as the temperature fluctuations are rather small.

 

[L_Sludger]

Next step is 85w140 gear oil.