Sunday, Mar 09, 2008 at 16:07
The specs for the 5w 30 fully synthetic means it will handle extreme heat and pressures. I also think that the extremely fine tolerances that they achieve these days of engine design requires a fine oil otherwise everything will not be fully lubricated. Prior to the CRD I had a 4.7 V8 Laredo which had the same oil spec and I always insisted on full synthetic.
I remember I forgot to tell the service manager at one of the oil changes and they put in Castrol Magnatec 5w30 and the engine sounded noisier at idle, I took it back and asked what oil they had used when told it was Magnatec I dumped it and replaced it with a full synthetic and the noise went so what this said to me was the full synthetic was obviously lubricating far superior to the magnatec even though the viscosity was the same.
My son has an ss commodore and he changed to a full synthetic same deal quietened the engine.
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