Newer oils bad for older SLs? - PeachParts Mercedes-Benz Forum

MadMike · #1 03-05-2008, 12:46 PM

I have heard from a couple of different sources that the newer SL or SM designated oils are problematic for older engines. It would seem that they dramatically reduced the amount of zinc in the oil. This results in high rates of wear on the top end with the camshaft being hit particulary hard.

Anybody know anything about this and what should we do? There are no longer any SJ designated oils available.

I had to replace the drivers side cam on my 76 450SL last summer. That was a very expensive repair. I had been running Valvoline MaxLife 10w40 here in Wisconsin and changing it about every 3K or so. (This is not the synthetic or synthetic blend). Car always had good oil pressure and did not use oil.

Anybody know anything about this? Should I be using something else?

ScottinSoCal · #2 03-05-2008, 04:15 PM

Quote:

Originally Posted by MadMike

I had to replace the drivers side cam on my 76 450SL last summer. That was a very expensive repair. I had been running Valvoline MaxLife 10w40 here in Wisconsin and changing it about every 3K or so. (This is not the synthetic or synthetic blend). Car always had good oil pressure and did not use oil.

This was more likely due to a failed oiler tube than it was the type of oil you used, especially if you changed it every 3K miles. The plastic clips that hold that tube in place get old and brittle and crack, and it stops lubricating the cam shaft. An oiler kit for both sides is about $6, and well worth the time you'll spend. Although it probably got replaced when you had the cam replaced. But did he do the passenger side?

MadMike · #3 03-05-2008, 04:26 PM

No. They only did the drivers side. However, they did have both valve covers removed. I know this as they were not reinstalled properly and I had to take them off and redo them myself. When I had them off, I did inspect the entire valvetrain, and everything is tight on both sides so I think it is ok now.

It is possible that the cam was just old and worn out. I am certainly not looking to go after them for the cost of a cam. I am just trying to get to the bottom of whether or not SM and SL rated oils are a problem for engines with flat tappet cams.

Anybody else know anything about this?

1989560SL · #4 03-05-2008, 04:39 PM

As I understand it, many older car owners are now using synthetic with good success. I'm currently using dino in my two M-B's without problems, changing every 4K.

MadMike · #5 03-05-2008, 07:07 PM

OK, I have looked into this the best that I can. This is what I have discovered, and this is what I am going to do;

Indeed it is a problem of accelerated wear on oils with low levels of ZDDP. Oil companies were mandated to lower ZDDP levels in most oils to lengthen the life of catalytic converters.

Mobil has confirmed this to be an issue for certain performance engines and some Mobil1 products still have higher levels of ZDDP.

For my mb, I will switch to Mobil1 15w50. It might create some seal issues, but minor seapage is better than major wear.

Good luck to all.

sokoloff · #6 03-05-2008, 07:10 PM

Mobil 1 15W50 and 5W40 have the highest zinc content in the Mobil 1 line. The Mobil 1 site has a chart giving the specs of all of their oils.

82gray380 · #7 03-05-2008, 07:41 PM

I do believe this oil damage issue is more during the breaking-in of rebuilt engines. If your talking about older engine which have miles on them, I don't think the lack of ZDDP is as big an issue. There have been reported very early engine failures (usually cams going bad) when not using a ZDDP additive while breaking in newly rebuilt engine. I just rebuilt an engine on my Triumph TR3 and I purchased a ZDDP oil additive for the break-in period. I haven't started it yet, but I did do a fair amount of research on the subject and this was what I concluded about the oil issue. Considering I have several older cars, for PEACE OF MIND I do add a ZDDP additive to all my older cars oil once every several oil changes. But that is just for precautions.

waybomb · #8 03-05-2008, 08:32 PM

I now only use off-road only oils in my boat. For a while, I was able to use Rotella T, but they started reducing the zddp in it as well.

The biggest effect is on non-roller cam engines, such as those in my boat. After wiping flat a few cams, I learned alot about this.

Only off-road-only oils now have the old level of zddp in them.

I also use Mobil One Gold Cap in the 97 and 01, and use off road in the rest.

ScottinSoCal · #9 03-05-2008, 09:53 PM

Quote:

Originally Posted by MadMike

No. They only did the drivers side. However, they did have both valve covers removed.

I'd check the passenger side oiler tube and replace the plastic if necessary. As far as oil goes, I've only used Mobil 1 5W-50 since I got my car and haven't had a problem with it. I also use it in my Honda hybrid and my Toyota.

Strife · #10 03-06-2008, 02:55 AM

Quote:

Originally Posted by MadMike

No. They only did the drivers side. However, they did have both valve covers removed. I know this as they were not reinstalled properly and I had to take them off and redo them myself. When I had them off, I did inspect the entire valvetrain, and everything is tight on both sides so I think it is ok now.

It is possible that the cam was just old and worn out. I am certainly not looking to go after them for the cost of a cam. I am just trying to get to the bottom of whether or not SM and SL rated oils are a problem for engines with flat tappet cams.

Anybody else know anything about this?

If you removed and reinstalled the oiler tube fittings after someone else had installed them, you should install a new set. These pieces are barbed and I don't think they grab as well the 2nd, 3rd, 4th time as they will the first. It specifically mentions in the shop manual to swap them out if they are removed at all. They might look ok now, but a few years from now with high oil pressure in the winter...who knows?

Did the person who installed them first not get them in the "V" entirely?

Philoprof · #11 03-06-2008, 08:22 AM

Quote:

Originally Posted by Strife

If you removed and reinstalled the oiler tube fittings after someone else had installed them, you should install a new set. These pieces are barbed and I don't think they grab as well the 2nd, 3rd, 4th time as they will the first. It specifically mentions in the shop manual to swap them out if they are removed at all. They might look ok now, but a few years from now with high oil pressure in the winter...who knows?

Did the person who installed them first not get them in the "V" entirely?

I wanted to mention that the barbed, plastic pieces for installing the oiler tubes that I recently bought from the Benzbin were so loose I couldn't use them. I was just wondering if anyone else has had this problem with oiler kits?

MadMike · #12 03-06-2008, 10:18 AM

Thanks for the help everyone.

I have not removed the oil tubes at all. All I did was remove the valve covers and reinstall them. The mechanic did not put them back on properly and they were leaking. When I had them off, I did inspect the rockers and oil tubes, but did NOT remove anything. Everything is tight. I will leave it as is for now.

Car is still in winter storage. I think I will reinspect the oil tube on the passenger side when I get it out.

ScottinSoCal · #13 03-06-2008, 12:22 PM

Quote:

Originally Posted by Philoprof

I wanted to mention that the barbed, plastic pieces for installing the oiler tubes that I recently bought from the Benzbin were so loose I couldn't use them. I was just wondering if anyone else has had this problem with oiler kits?

I've heard there are two sizes, but I can't confirm or deny that because all my experience is with 117.985 engines. Verify you got the right kit for your year car.