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1987 US 560SL<br> <br> Just wondering what engine oil everyone is using for the 560SL. Currently, I use 20W-50.<br> <br> Has anyone tried using synthetic on this vehicle? I've been reluctant to use synthetic on anything 1990 and older. If you have used synthetic on this vehicle, what weight oil did you use?<br> <br> Though I doubt it would work, can 5W-XX oil be used in this engine? I'm thinking it would be too thin for the seals...<br> <br> Any opinions?<br> <br> <br> <br>
 

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On by 83 380SL, I have been using synthetic for about 2 years. I use 20W-50. <br>
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I was told to expect leaks. But they never materialized. (The first time I changed to synthetic, I did see a few drops under the car; then I realized that I failed to replace the washer on the drain plug. Silly me!!)<br>
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The car does run a bit cooler and in So Cal, this is important.<br>
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Good luck.
 

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20W-50 synthetic. What brand do you use?

<br> 20W-50 synthetic should have the same viscosity as regular 20W-50, so I wouldn't think you would get any leaks (unless that seals/gaskets are really old). 5W-50 oil is really thin and my concern was that it being such a low viscosity oil, it would probably leak out the seals. I've already seen happen on an old Datsun 260Z.<br> <br> Common synthetic weights I've seen are 5W-50 (my favorite), 10W-30, 5W-30, 10W-40.<br> <br> I've never seen 20W-50, but I suppose they'd have to make a synthetic in that weight since it's pretty common in the older cars.<br> <br> I was hoping to get away with 5W-50 oil since I use that in all my cars (except my 1978 Datusn 280Z which still takes traditional 20W-50).<br> <br> Been using 20W-50 regular oil in the 560SL as well, but was hoping to see if anyone has tried 5W oil.<br> <br> I guess I can always stock up on 20W-50 synthetic.<br> <br> <br>
 

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Re: 20W-50 synthetic. What brand do you use?

The reason for the leaks, I am told, was that synthetic oil has better impregnating properties than regular oil. The synthetics will seep through seals and gaskets that have not been saturated with the oil from the begining. <br> <br> If you do not show any leaks, all the better.
 

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Re: 20W-50 synthetic. What brand do you use?

Used Mobil1 15W-50 on my 88 560SL for over 4yrs. no leaks, and running strong.
 
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