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Model Specific Questions and Info => MK2 Golf/Jetta and Audi 5k => Topic started by: thomas m on May 20, 2018, 10:53:48 am

Title: Would You Use This Oil In Your Diesel Engne??
Post by: thomas m on May 20, 2018, 10:53:48 am
Open question here.

Would You Use This Oil In Your Diesel Engine??

https://mobiloil.com/en/motor-oils/mobil-1/mobil-1

Click the 15W-50 tab.

Just wanting to get reactions from the crowd.

Thanks
Title: Re: Would You Use This Oil In Your Diesel Engne??
Post by: ORCoaster on May 20, 2018, 11:17:45 pm
NOPE!


My diesel is so old I would have leaks all over the place I fear.  Besides that I don't see where that oil is actually made for all the soot that is part of the diesel burn process.  The Rotella Diesel formula is what I use and buy when it goes on sale for 13 bucks a gallon locally.
Title: Re: Would You Use This Oil In Your Diesel Engne??
Post by: libbydiesel on May 21, 2018, 01:11:36 am
I've switched many high mileage engines to synthetic and have never had it cause a single leak, ever.  I'm convinced that's a myth. 

It meets CF rating.  Would I use it?  It depends on which engine.  I have 5 vehicles with AHU and ALH engines and would not use it in any of those as it does not meet spec for them.  I have two other vehicles that it would meet the spec on ('79 rabbit, '85 gasser vanagon) and I'd be ok with using it in either of those. 
Title: Re: Would You Use This Oil In Your Diesel Engne??
Post by: Dakotakid on May 21, 2018, 02:52:19 am
I'd use it if my neighbor had it and left his garage unlocked..................
Title: Re: Would You Use This Oil In Your Diesel Engne??
Post by: thomas m on May 22, 2018, 04:19:04 pm
Quoted from the Mobil 1 data sheet:

"According to ExxonMobil, Mobil 1 15W-50 is of the following quality level:
    API  CF"

I'm not sure what "is of the following quality level" means, but it is a "CF" API designation.

To quote the API.org website, CF is an obsolete designation "Introduced in 1994. For off-road, indirect-injected and other diesel engines including those using fuel with over 0.5% weight sulfur. Can be used in place of CD oils."

So, it is a diesel rated oil. Whether it is too heavy for an old engine is a matter of opinion and experience.

My Delo 400 SAE 40W for diesel engines is rated API CF also.

Title: Re: Would You Use This Oil In Your Diesel Engne??
Post by: libbydiesel on May 22, 2018, 06:49:42 pm
15W-50 is fine for summer.  Your penguin avatar pic makes me wonder if it might be too heavy for at least some of the year where you are. 
Title: Re: Would You Use This Oil In Your Diesel Engne??
Post by: ORCoaster on May 22, 2018, 10:08:37 pm
Not too heavy of an oil.  It is only 15W and gives the protection of 50W   That is how I read that label.  Good to know it is diesel rated. 

And Yeah where did the sulfur in the diesel go?   Not up in smoke that is for sure. 

Title: Re: Would You Use This Oil In Your Diesel Engne??
Post by: theman53 on May 23, 2018, 07:44:12 am
15w when cold 50 when hot is how I read them.
Title: Re: Would You Use This Oil In Your Diesel Engne??
Post by: thomas m on June 04, 2018, 08:28:37 pm
See this link or read below: this is Castrol's take on the viscosity numbers.


https://www.castrol.com/en_gb/united-kingdom/car-engine-oil/engine-oil-viscosity.html (https://www.castrol.com/en_gb/united-kingdom/car-engine-oil/engine-oil-viscosity.html)


How is Viscosity Measured?

The viscosity of oil changes with temperature, therefore multigrade oils were developed to provide protection across a range of operating temperatures.
The SAE (Society of Automotive Engineers) scale shows the viscosity of oil at both hot and cold temperatures. Thatís why the viscosity grade on the oil bottle is made up of two numbers.

Low temperatures

The first number followed by the letter W describes the viscosity of oil at low temperatures (the W stands for winter). The lower the number the thinner the oil.
A thinner oil at low temperatures is good because it flows more easily and is therefore able to protect the engine when it is first started from cold. If oil is too thick when cold, it will not circulate freely and will reduce fuel economy.

High temperatures

The second number describes how thick the oil is at the engineís normal operating temperature.
The higher the second number, the thicker the oil. If it's too thin when hot, it may not protect effectively. If it's too thick, you lose efficiency.

The correct viscosity grade will be displayed in your car handbook.