FYI- Just switch my 6.9L Ford (Banks turbocharged) diesel over from Rotella T 15W40 CI-4 to Rotella 10W30 CJ-4. Absolutely no differences to note initially. Even the oil pressure reads the same on the stock numberless gauge. Have sent the 15W40 in for analysis and will do the same with the 10W30 about this time next year for a comparo (it gets a 1 year or 6K mile change, though this year the truck only acquired 5300 miles).
From 15W40 to 10W30
- Thread starter Jim Allen
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I went the opposite way...Amsoil Series 10W30 to Amsoil (AME)15W40.
Many, if not most, Ford "oil pressue" gauges are bogus. They work like an indicator light, either on (somewhere in the middle of the numberless gauge) or off (all the way to the left on the gauge). Hopefully they put something better in the diesels, but I doubt it. You can tell if it is a real gauge in that the oil pressure should vary with RPM on a well warmed up motor.
Anyway, what grade does the book call for?
You may be by a Murrays Auto. They sell Motorcraft Diesel oil in 15w40 and 10w30, both in quarts.
Anyway, what grade does the book call for?
You may be by a Murrays Auto. They sell Motorcraft Diesel oil in 15w40 and 10w30, both in quarts.
TallPaul: Oh, I researched this first, never-you-fear! The '86 manual calls for 30 or 10W30 in my climate, but I have used 15W40 for the past 20 years almost. Five years ago I lived in a much hotter climate and the 15W40 was more appropriate. I guess you could say that I'm in an overlap area here where both fit in the climate range, but the 10W30 is better in the winter range. This is somewhat an experiment, the ultimate goal being to aid lube flow on cold starts, and starts in general, and for MPG (all ala the Doc Haas "thinner is better" philosophy). I'm confident it won't eat the motor, but the UOA will tell the tale over the next year. And whatever tale it tells, I'll tell YOU! No ego stake in the results at all!
As to the gauge, I had forgotten that aspect of Fords... but concede your point. On mine, it does vary somewhat but moves very slowly from high speed operation down to idle on a warm engine. I had a mechanical gauge in it some years ago, but it blew the line in the cab. I had an "Exxon Valdez" moment that I can still find evidence of 10 years later. I replaced the gauge with a voltmeter. The wife's slacks went into the trash... ahem! I probably oughtta install a "real" gauge. But it will be electric!
I'll stick with Rotella, thanks! Had outstanding UOAs with it (or Delo) in all my equipment and I can usually buy it cheaper than MC to boot. Besides, isn't MC "Dictator Oil" (Conoco)?
As to the gauge, I had forgotten that aspect of Fords... but concede your point. On mine, it does vary somewhat but moves very slowly from high speed operation down to idle on a warm engine. I had a mechanical gauge in it some years ago, but it blew the line in the cab. I had an "Exxon Valdez" moment that I can still find evidence of 10 years later. I replaced the gauge with a voltmeter. The wife's slacks went into the trash... ahem! I probably oughtta install a "real" gauge. But it will be electric!
I'll stick with Rotella, thanks! Had outstanding UOAs with it (or Delo) in all my equipment and I can usually buy it cheaper than MC to boot. Besides, isn't MC "Dictator Oil" (Conoco)?
This would then explain a great many things about my dad's Ford F-150 and that gauge package...
The 6.9L have a real oil pressure gauge in the dash that uses a variable resistance sender. IIRC the dash itself had something to dampen the movement of the gauge though.
Jim, I think you'll be fine with that oil. I doubt you'll see much of a change one way or the other in the UOA. It might even be better with the 30wt if the truck gets started frequently.
If that truck has a 5 speed in it you don't even need an alternator or starter, just bring a set of ramps with ya and back up them and bump start down hill
Jim, I think you'll be fine with that oil. I doubt you'll see much of a change one way or the other in the UOA. It might even be better with the 30wt if the truck gets started frequently.
If that truck has a 5 speed in it you don't even need an alternator or starter, just bring a set of ramps with ya and back up them and bump start down hill
1040: Yeah, the gauge does appear to egister variably as you say, so other than not being able to correlate a number to a position on the gauge, I'm set. As I said, the pressure remains at approximately the same levels as before.
Nope, it's an automatic. It does still have the original starter in it, though. The truck has always started instantly. Hey, I could install a hand crank! I have hand started engines almost as big (1918 & 1919 389ci Wisconsins in FWD Model B 4x4s)
but they had 4:1 compression ratios. Or a hydraulic starter with a hand pump and accumulator!
Nope, it's an automatic. It does still have the original starter in it, though. The truck has always started instantly. Hey, I could install a hand crank! I have hand started engines almost as big (1918 & 1919 389ci Wisconsins in FWD Model B 4x4s)
I would do 40 wt in the diesel though a uoa would show the facts.
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