Originally Posted By: Jim Allen
Some of you may remember my oil filter bypass test of years ago. They may be still here. I noted the increased significant likelihood of bypass,especially on cold starts, or cool oil WOT, when using the 10W30 but only in very cold conditions with 5W20 combined with hi revs. Only when the oil was over about 180F was there little chance of bypass with 10W30 combined with high revs. In the short term, bypass events don't amount to much but I think long term and needless allowing bypass events to occur is counter productive.
OK a Question:
So far, all I see from the thicker is better crowd (hereafter abbreviated TIB)is that going one or two grades above spec'ed doesn't hurt their engine. OK,great! Can they demonstrate objectively that it helps in some way? Some objective testing, perhaps? Educate me!
OK then, compare TIB anecdotes to the way Ford validated 5W20 in a whole lot of testing. Of course it's not optimal in EVERY situation, they knew that, but they also accounted for it in the manuals and the situations where 5W20 wasn't in an optimal range is only for a small segment of operators.
If I saw the TIB posting some objective reasoning for the change, it would make more sense. For example, "My oil temp is running 250F and I tow these huge trailers 1000 miles at a shot, so I have gone up to a 0W40." THAT would make some good sense. Many of you guys are making a change with NO data and for no operational reason you can state objectively.
Most people spend 90 percent of their driving putt-putting around. That was true for me and if some of you remember, I had my truck instrumented to the hilt and datalogged a lot of stuff. My 5.4L seldom reached 200F bulk oil temp so my 5W20 was operating in the 30 grade range most of the time anyway. That's more than adequate protection.
In my instrumented run on 10W30 oil in that 5.4L VVT engine, I DID NOT note any change in engine noise. I DID note some slight (inconsequential) changes in VVT operation, many more oil filter bypass events (I live in a cold climate), a loss of MPG (in town with cool oil 2+ mpg, out on the road with fully warmed oil maybe 1 mpg). I DID see slightly higher oil temps (~5F IIRC). Anyway, didn't see any reason for a heavy oil so went back to a robust 5W20 (at the thick end of the viscosity range). My towing and hauling was usually of relatively short duration and infrequent, so I didn't factor that in. Plus, when I did do it, my highest EOT was 218F hauling a 2500# load of seed at 70 mph in ambient 85F weather. That's still well within the capabilities of a good 5W20s additive pack.
Anyhoo....
I had no horse in the viscosity race other than choosing the right one for MY situation based upon some objective means. Not everyone has the means I had to make the choice, ok. To me the logic in that case would be to stick close to the OE recommendation, which is based on a LOT of objective testing. If you live in a hot climate, and/or often run your vehicle hard, maybe a one grade jump is in order.
FYI, did the same for my old 6.9L diesel Ford, in which I run, and have for many years, 10W30. After monitoring oil temp and oil pressure for years, I determined 10W30 was in order, especially in a cool/cold climate. Some years back, I blew the heads off (Banks turbo installed in 1987 on an NA engine with a 21.6:1 CR). I decided to pull the engine to check everything as I updated to better head gaskets, studs and dropped the CR a little. The lower end was perfect! Decades of running 10W30... perfect!
Can you summarize your
1. Questions
2. Answers
in a laconic text, please?
I take it you had more than 32 sample vehicles in your experiment with more than 32 samples per vehicle to come to statistically valid trend observations and pattern recognition results.
