Originally Posted By: FiremarshalRob
Originally Posted By: bmwtechguy
I like a 40 grade in the 7.3 Powerstroke in the summer unless you are mostly running shorter trips. That engine design can really shear an oil. I'd hate to end up with a 20 grade at the end of the oil change, especially in hot weather.
There you go, busting my bubble!!!
Originally Posted By: Rumble
That's what I'm using in my '92 Chevy p/up. Was a little too thin for my Caddy though, so I'm using Delo 15w-40 until I come across some heavier weight T5 (15w/40?).
Rotella T5 can be found at Tractor Supply in 10w-40
Let me bust another bubble ...
PSDs only tend to shear thick oil. If you feed the PSD 10w-30, it will likely not shear much, if at all. I've seen this in what few UOAs exist with PSDs fed a 30 grade. It's my suspicion, backed up with a bit of anecdotal evidence, that the HEUI simply prefers the lighter grade oil. If you don't put it in, and use a 40 grade instead, it will chew it down to a 30 grade. But I've seen UOAs where a 10w-30 stays in grade in a PSD.
The wear metals in the UOAs suggest that the lighter grade was of no consequence. So, regardless if the oil shears, and the wear is not affected, why worry about it?
Further, the HEUI certainly starts up and runs a bit "better" with a thinner grade; I can personally attest to this when I ride in my neighbors 6.0L PSD. This is more of an issue in winter, so you may have little concern for this in LA, as opposed to us being in IN.
I use dino 10w-30 Rotella in my Dmax (not known to shear oil) and really use it hard when pulling my travel trailer in summer. It was 101 deg F one day in SD when I was running westbound, into a headwind, on I-90. I suspect 10w-30 can take the heat in LA.
The only potential issue might be that of a wee bit more evaporation. You may have to top-off just a tiny bit more, or not at all, depending upon your OCI duration.
I think you'd be very pleasntly supprised with the performance of 10w-30 in your 7.3L PSD, especially with a semi-syn. I would certainly make your garage stock supply a bit simplier.
As for your other two vehicles, I don't think it's a bad idea at all. As warm as you get in summer, and not that cold in winter, a 10w-30 vs a 5w-30 isn't really a huge issue. Again, the simplicity of the garage stock might make more sense than fretting over the "winter" rating here (5w vs 10w). They both are a 30 grade at full temp.
You can run some of your own UOAs and let us know. Sometimes, rather than live vicariously through others, we have to be the guinea pigs ourselves. I'm thought of as a heretic by some for running dino 10w-30 Rotella in my Dmax, but the proof outweighs others opinions! (Actually, this stuff is in my 1966 Mustang, my Goldwing, my Dmax, my Kubota tractor ...)
I hereby grant you permission to try it, and sleep well at night.
