correct oil

[gnj588d]

Hello again.does anyone know if its ok to use Castrol Magnetec 15w40 synthetic motor oil in the engine and the injection pump or should I stick with the old castrol GTX 10w40.Many Thanks Mike Rutledge.

[Shvegel]

Speaking as a lifelong mechanic I offer the following advice:

Synthetic oils from major manufacturers are great. I am particluarly a fan of Mobil 1 due to years of personal experience with customers who put 200 to 300k on turbocharged engines I have torn down at the customers request "just for a look" that looked beautiful inside.

The downside of synthetics is that they tend to have a very strong detergent package(helps to keep the engine clean during those long change intervals) Which means that it will clean all the goo out of your 40 year old engine, all that sound great on paper but some of that goo may be keeping the oil from leaking out of your engine. Seals and gaskets loose their elasticity and the goo may be the only thing between a relatively dry engine and a sieve. Especially since these engines have a chunk of wax encrusted(graphite on the replacements)fiber that seals the oil at the rear of the crankshaft. Since this seal is only replaceable by removing the pan and the pan is only removeable by pulling the engine having a major leak there is a bad day.

As for the injection pump that is a pretty low load application so probably OK there.

All that said my daily drivers get Mobil 1 and my recently rebuilt 280SL gets good old fashioned GTX.

[DavidBrough]

Hi Mike,

There has been an awful lot written about various oils on this site and a search will return you more thoughts and comments than there are hours available to read them. As ever with these things you won’t get a definitive answer either but, it will give you lots of useful information and insights if you have the time.
 
The main issue as I understand it is the leakage possibility outlined by Shevegl. However if you have a clean/recently rebuilt engine you do have a choice. I took the view that I prefer frequent oil changes especially as the car does not get a lot of use during winter so I use the oil it was designed for at £10 for 5 litres instead of synthetic at £30/50 and change it twice a year or every 3,000 miles.

Hope that helps.



David Brough
1969 280SL

[gnj588d]

Hi David.Just been to Halfords for my GTX but noticed the wording on the container has changed,for modern engines manufactured after 1990 I wonder have they changed the fomulation making it less suitable for our old engines,has it always been 10w40 also its £17 now Iwonder what alternatives do we have.Hello Shevegl do you still get the original GTX Best Regards Mike Rutledge Liverpool.

[DavidBrough]

Hi Mike,

Sorry for the delay in replying, been a bit busy.

I use Halfords own brand 15/50 basic mineral oil for pre 1980 vehicles which comes in a red container. This was recommended to me some time ago as a good quality own brand product and it has worked very well for me. In truth, my car has a pretty easy life with regular but easy summer use and irregular winter runs mainly to burn off any moisture and keep thinks in tune. I never let the oil get dirty so really begrudge paying for extended life I just wont use.


David Brough
1969 280SL

[rb6667]

The oil today is not what it was just a few years ago.  Since 2006 oil sold in the US has no Zinc in it.  That's what protects our flat/solid  lifter engines. I started see this info a few years ago, and thought it was just rumor.  Seems the feds made the oil companies take zinc out because it poisons cat converters.  Solution:  Run Diesel oil like Chevron Delo or Shell's Rotella.  Racing oil also still has zinc it it as well.  In 2007 the feds stuck again, even Delo and Rotella have reduced zinc, but still enough to protect our engines.  There has been a lot of discussion on this topic on other forums.  I believe it all to be true.

I am now running Rotella 15-40 in all my flat tappet engines.  If you look at the label, it is approved for gasoline or Diesel engines.  

rb6667

rb6667

[Naj ✝︎]

David,
 

quote:I use Halfords own brand 15/50 basic mineral oil for pre 1980 vehicles which comes in a red container.

Isn't 15/50 too 'heavy' for a rebuilt engine?

Did you fit the higher HP starter?

naj

68 280SL

[Rolf]

I talked to a product specialist who works for the same oil company as I do. He said there were some regular motor oils made in the US that contain zinc. He suggested using a diesel oil that was either 15w-40 or 10w-30 which contain a higher concentrate of zinc.

Rolf
1966 230SL Auto
1992 300D

[JimVillers]

Everything said about the benifits of using an oil with zinc is true and all US automotive oils (spark ignition) do not have any zinc (zero).  Castrol GTX Diesel 15W-40 is available at most auto parts stores and it contains 0.13% zinc (per its data sheet).  

If you have any questions about an oil, search on-line for the data sheet.  The only oils with zinc sold in the US are marketed for deisels, motorcycles or racing oils.  The GTX deisel oils still retain the API SL and SJ certifications for spark ignition engines.    

This subject is IMPORTANT.

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor, MGB 5-Speed

[harleydan]

Jim,

If I may be so bold to ask....what specific oil do you personally use in your own W113?  If it is good enough to be used in your own car, then I for one would surely use the same in mine.

Cheers/Thanks,
Danny
1970 280SL silver Euro 4 speed

[deacon]

OK - I know I'll get jumped on, but I might learn something.

I just brought my 65 230 in to my mechanic because when still a little cold when I excellerated through 3500 rpm I got a flapping sound.  Maybe piston slap, maybe worse...  my mechanic changed the oil and replaced it with Swepco (also seen as Sweepco) 15w40.  Problem gone.  Should have asked why.  I will and follow up.

David

David
65 230SL
Blue Grey 162 - manual

[Benz Dr.]

15 W 40 is very high in detergents for use in diesels. I've used this oil in some of my cars before without problem but I kind of like 10 W 40 better for colder weather.
Zinc is an anti wear additive and gear lube is rich in the stuff. I think synthetics pretty take care of these problems. Not sure why more people aren't using them.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061

[JimVillers]

Danny .... I have Castrol GTX Diesel 15W-40 in my car.  Before researching this topic, I also was a synthinic advocate.  At this point, I do not know what to believe as the lawyers and marketers have so filled the topic that it is hard to know what to believe.  I began with the understanding that zinc is critical to the longevity of older engines.  Lots of arguments that the modern oils are as good as the oils of the 1970's but never a statement that says that the current oil has the same protection as an oil with the zinc addidive (ZDDP).

Until someone presents a factual argument that the diesel detergents are  more of a risk than lack of zinc, I'll continue to use a diesel formulated oil with zinc.

Anyone interesed in a good starting point should read "Is Oil Killing Our Cars". http://www.minimania.com/ArticleV.cfm?DisplayID=1922

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor, MGB 5-Speed

[harleydan]

Jim,

Thanks...I'll switch over to your oil as soon as possible.

In the article "Is Oil Killing Our Cars', it has:

"From Castrol: We are beginning to see a pattern emerging on older cars. It may be advantageous to use a non-approved lubricant, such as oils that are Diesel rated, 4 Cycle Motorcycle oils and other specified diesel oils. They will be supplying “new oils” specifically for our cars in early 2007."

Have you heard if Castol's "new oils" are available yet or when they will be available (it was mentioned early 2007)?  And if you do change to another oil for your W113, please keep us informed.

All...has anyone used a 4 cycle motorcycle oil in their W113?  With the username of "harleydan", I should know what ingredients are in the oil that I use in my motorcycle but I don't.  I'll stop by the motorcycle shop to see....hopefully less detergents than diesel oils but with ZDDP.  Would it be something to use the same oil for my Harley and Pagoda

Nevertheless, I'll still stick with...whatever oil is currently used by Jim on a regular basis, then I'll use that oil also.

Why take chances with our Pagodas...

Cheers/Thanks,
Danny
1970 280SL silver Euro 4 speed

[Raymond]

When I first read this post, it alarmed me.  So I started looking for all the info I could find.  Two weeks later, my eyes are blurry from reading internet articles about this.  There is a lot of conflicting information but the general picture I can get is that the problem exists almost exclusively with flat tappet engines like the MG and American muscle cars. The lack of ZDDP doesn't seem to be a problem for cam follower engines like ours.  

In one article from Hot Rod magazine, this quote summarizes the case for diesel oils like Rotella; "Diesel oils also add a superior detergent package that can keep the piston rings cleaner for better oil consumption control. The drawback, if any, would be on a high-mileage engine where blow-by can cause detergent to accumulate in the combustion chamber, possibly contributing to detonation."

In my case, with just a few thousand miles on a total overhaul and after having read all I could stand, I'm not ready to stop using the synthetic I have used since after break-in.

Ray
'68 280SL 4-spd Coupe