Some background. I have been using Mobil 1 in everything but my Triumphs and lawnmower since the early 90s. Obviously, it is in my Redline and I switched my Outlook to Mobil 1 at 3000 miles. Also, I use Wix filters on everything INCLUDING my lawn tractor. Okay ----
Two years ago my 97 Chevy van (5.7 engine) needed the intake manifold replaced. Just like the V6s that have a national settlement for intake gaskets, the Dex-Cool coolant kills the V8 intake gaskets as well. I had the intake gasket done at a very good shop in my old Snap-On territory. Immediately after the repair I noticed a loss of oil pressure at idle when the engine had fully warmed up. The shop replaced the sensor which seemed to resolve the issue .... for a couple days. Another sensor, same thing. I asked them to check the oil pressure and was told that the tech said the pressure was good. I asked about running temps and was assured all was okay. Since then I have put about 7000 miles on the van (doesn't get driven much since I bought the Sky). Well, yesterday I was forced to replace the fuel pump (in tank, electric) so I took it to what was my Saturn store (now selling 150 used cars a month and servicing them and street customers) for the repair (not a one man job). While there there was suddenly a new noise (lifters rattling real bad) so the tech checked the oil pressure. ZERO at idle. Zilch, nadda, zip. It was nearly a
moment. With the fuel pump resolved I drove the van home.
Today .... up on jack stands to pull the oil pan and inspect the disaster. First the oil was dumped and there was some "fuzz" on the magnet on the end of the drain plug. Down can the pan. Besides the dirty oil, no trash or anything else was present. I pulled a couple rod caps to inspect the expected damage. The journals were perfect while the bearing shell had some wear. But at 85,000 miles and the unintentional abuse, it seemed acceptable. So, off to the parts store for a new high volume oil pump and pan gasket. After buttoning everything back together a new filter an 5 quarts of 5W-30 went in. WELLLLLLLLLLLLLL ,,,,,,, the engine fired right up , the oil pressure (cold) was 40 psi @ idle. After driving the van to bring it up to temp the idle pressure is about 25-30 psi and running it's about 50-60. This is substantially above factory specs but I installed a high flow/pressure pump as I feared excessive clearances in the engine would need to the extra flow. Factory calls for 6 psi at 1000 rpm and about 30 psi at 3000 rpm. I am guessing that a standard pump would have been fine, but I wasn't going to do the job twice.
Bottom line, I will never be persuaded that the Mobil 1 was not the reason the engine survived through all the abuse of idling at ZERO psi so MANY times and for SO long. Will I ever use anything else? Nope. I am SO happy the fuel pump failed !!!!!!
Just to make something clear, I am aware that some damage MUST have been done, and a lot of evidence was thrown away with a couple oil filters. But, it still had all five quarts of oil in the engine after 5000 miles and there is NO engine noise at all.
