A few weeks ago I traded my 1984 diesel Rabbit for a Certified Pre-Owned
2002 Jetta powered by the 1.9L turbocharged diesel. With only 30,000 miles, this machine still has some time to go under the new-car warranty, before the CPO warranty takes effect.The salesman's parting shot was, "You can get oil changes for half price from us, for as long as you own the vehicle."
After a week or so of fun during my 80-mile commute, I called the dealership's service manager and enquired about oil changes. He corroborated salesman's last remark.
I also asked how much oil would cost if I purchased it from the dealership -- that 5W-40, CF-4 or CG-4 as specified in the owners' manual.
I was somewhat surprised when he said, "Oh, we put Rotella 15W-40 in those engines."
"And doing so doesn't void the warranty?" I asked. He insisted it would not.
Not entirely satisfied, I called my independent mechanic, who kept my
1984 Rabbit alive through two engine rebuilds, chronic timing belt slippage, and various other crises. He said, "The service manager is right; 15W-40 will work just fine in your 2002 Jetta."I don't know enough about either the newer engines or oils to decide if I should be suspicious or not.
It does strike me as false economy to put petroleum-based oil of incompatible viscosity into an engine like the 1.9L TDI if it will shorten the service life ... even if the newer oils (or synthetics) cost nine to twelve dollars a quart.
Any thoughts?