Posted by RDavis on Thursday, December 05, 2002 at 3:31AM :
In Reply to: Re: Anyone use Mobil 1 10W30 synthetic oil? posted by John Diehl on Thursday, December 05, 2002 at 1:00AM :
I put mobil 15-50 syn. in my 1990 mazda PU after it reached 100,000mi. I had been using mobil 20-50 since breakin mileage was reached
with no problems. The moble syn 15-50 seemed to lack in viscosity as the lifters began to clattered and other strange faint noises were detected.
After about a week of enduring the noises and fearing some sort of eng. damage due to what I percieved was a lack of viscosity, I drained out the syn. oil and filter,replaced
with the mobil 20-50 I had been using and after approx.50mi.I drained again and refilled with new 20-50 oil and filter.
The noise was immediately gone and even eng. power seemed to improve. It now has 207,000 mi. and the engine doesn't smoke or leak.
Personally I believe syn. oil may perform well in a new engine with tight tolerances but, after any
bearing that works on a oil wedge begins to wear, syn. oil may lack the viscosity or maybe is just too slick to adhere to the metal to give adequite pressure for the oil wedge to work properly.
Maybe it was just my eng. and others have had no problems but I have heard others complain after switching to syn. oil.
Quality oil and filter with regular 3-5,000
mi. changes will do as well as most anything out there to give long eng. life. Good driving habits and good maint. is hard to beat.