Thin vs Thick Discussion, Chapter 6

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Jan 9, 2005
Sarasota, Florida
Motor Oil 106
Part Six. Personal recommendations (Updated in 2021)

There are many more types of oils one can select from today. For any given single grade and brand there may be several levels of Good-Better-Best “general” motor oils. Then we have break-in, turbo, high milage oils, heavy duty oils. There are fully mineral based oils, semi synthetic, fully synthetic and maybe several types of each of those. Then we have several specifications available, SN, SN conserving, SN Plus, SP... as well as older specifications, SM, SL... as examples. Wow. How does one keep up?

Certainly one cannot go bad by using the recommended oil for your car as suggested in the owners manual. As the car ages it may be useful to use a high milage variety if it appears the seals are starting to leak. These formulations often contain higher levels of additives that enhance the integrity of seals. But thats a whole topic in itself. Seals in cars that are not used often enough usually leak. Ferrari engines are famous for this as they are simply used infrequently. For those who drive them all the time the seals do not leak.

If your car does not specify a synthetic it may be a waste to use one unless you are using your vehicle in some unusual manor. A compromise may be to use a semi synthetic. One of my favorite motor oils is Motorcraft semi synthetic 5W-20. I have used this in every high powered car we have owned except for the Enzo. Oil analysis revealed normal wear.

I also like Red Line 0W-20 that I have tested in these same engines. When changing gear oils I use Red Line exclusively. For gear oils I also generally use a thinner grade than specified by the particular engine. Note that I never use my vehicles at their upper end of stress. Though I may have filled my SUVs to the brim while transporting items I have never done so while also towing 8,000 lb. trailers up hills, mid-summer in Arizona.

My favorite oil is Renewable Lubricants Incorporated. I do not care that they are biodegradable. Everything is recycled anyway. The results of oil testing in my Enzo was a determining factor as here: Dropping from a 60 Grade to a 20 Grade Oil Revisited.

It seems that many engines work best with a multi-grade 30 weight / grade oil. Others would do better with a 20 grade oil and few would require a 40 grade oil. You can only determine what is best by experimenting. Admittedly I did not think my Ferrari Maranello would need a 20 grade oil (I used 0W-20 Mobil One). In truth I could actually have used a 10 grade oil. A 0W-10 would be good but it simply does not exist for normal use. Red Line does make 5W and 10W oils (this acts as a 0W-10 multi-grade oil) but they are for racing only. One Formula 1 team has actually used off the shelf oils from Red Line.

If while on the road you are forced to add oil there are rules. Let us say for example that our engine has synthetic Mobil One 0W-30. Use the same type and brand if you can. If you are using Mobil 1 then it is acceptable to mix different grades but use a close grade when possible. It is not a good idea to mix say 1/2 your oil tank with 0W-30 and 1/2 with 15W-50 Mobil 1. If there is no Mobil 1 available then use the mineral based Mobil oils next.

The last choice is to mix a synthetic of another brand. They should not react adversely if mixed but it may dilute additives. One motor oil company may use a different additive to do the same job as another company. If you mixed the oils 50-50 you would dilute each of these differing chemicals in half. This would not be ideal. Use this combination if you must but only until an oil change can safely be performed some time soon.

I personally used 0W-20 Mobil 1 in the 575 Maranello and for the first oil change I drained the Murcielago’s (OEM) 5W-40 Agip and replaced it with 0W-30 Mobil 1. The engine became much quieter. A valve tappet like noise disappeared. I then used the 5W-20 Red Line in the Lamborghini. Used oil analysis showed that this oil worked well for my non racetrack application. The same oil went into my original Maybach 57. My Enzo Ferrari called for the Shell Helix Ultra racing 10W-60 but I have used the Castrol Syntec European Formula 0W-30. I last used Renewable Lubricants Inc. (RLI) 0W-30 in the Enzo and 0W-20 RLI in the new Maybach 57s AMG.

If you want to try different oils you have to try by experimentation what operating oil grade your engine requires. In all cases however, you want the oil that gets least honey-like at startup and thins to the appropriate thickness for normal operation. Always recheck the oil label as they change a lot.

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