opfor2
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So what is the opinion on using Shell's Rotella 15w-40 diesel motor oil on out Tahoe's?
Shell Rotella 15w-40 motor oil
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I use it in my 1929 Model A Ford. It's definitely not a winter oil for a tahoe
donjetman
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T4? T5? or T6?
15w40 is not a good viscosity for winter.
If there ie a 5w40 or 0w40? this would be better viscosity for winter time.
15w40 is not a good viscosity for winter.
If there ie a 5w40 or 0w40? this would be better viscosity for winter time.
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opfor2
Full Access Member
Oil pressure and viscosity run the DOD/AFM (if you still have it) AND
the VVT. Gen IV engines also call for synthetic oil that meets dexos requirements.
IF you are in a hot climate and for some reason feel you need a little "thicker" oil,
then you could do a 5w40 synthetic or even a 10w30 synth oil.
The only reason for going with a diesel oil disappeared about 10+ years ago
when used on flat tappet engines as they needed the zinc and phosphorus that
the diesel oils still had (but it's gone now). So no reason to use it in a gas
automotive application
the VVT. Gen IV engines also call for synthetic oil that meets dexos requirements.
IF you are in a hot climate and for some reason feel you need a little "thicker" oil,
then you could do a 5w40 synthetic or even a 10w30 synth oil.
The only reason for going with a diesel oil disappeared about 10+ years ago
when used on flat tappet engines as they needed the zinc and phosphorus that
the diesel oils still had (but it's gone now). So no reason to use it in a gas
automotive application
I'm pretty sure Rotella 15w-40 still has zinc in it. But I definitely agree there's no need to run it in the Tahoe or any modern gas engine for that matter.
ChevySSR
TYF Newbie
my 2014 SSV maintenance records showed 15w40, when I was picking Tahoe up from the department, I asked to talk to the maintenance crew and they told me to keep on 15w40, they do that for all fleet cars after 90k miles. According to them this prevents many issues with oil consumption later on. I thought about going back to 5w30 in the winter, but for now am on 15w40.
BabushkinMechanic
TYF Newbie
Lol I've been fighting low oil pressure or what everyone considers to be low 18-20psi at hot idle for a year now on my wifes hoe since we got it. Changed o ring, leaking oil cooler/ oil pan gakset leak ect and it held better pressure at 10w-40 last oil change than it ever did with 5w-30 and im in georgia, cold we will ever see is the frost on the grass for half a second. A PPV with 115k with god knows how many idle hours. I have HP tuner software and played with engine idle rpms, noticed they hover right about 480-510rpm. LOW, when i increased it to 650 it held at 25psi, just sayin.
So yea 15w-40 Rotella is going in right now. Kept trying to make sure i do everything per the manual standards. Even the manual can be wrong
So yea 15w-40 Rotella is going in right now. Kept trying to make sure i do everything per the manual standards. Even the manual can be wrong
Lol I've been fighting low oil pressure or what everyone considers to be low 18-20psi at hot idle for a year now on my wifes hoe since we got it. Changed o ring, leaking oil cooler/ oil pan gakset leak ect and it held better pressure at 10w-40 last oil change than it ever did with 5w-30 and im in georgia, cold we will ever see is the frost on the grass for half a second. A PPV with 115k with god knows how many idle hours. I have HP tuner software and played with engine idle rpms, noticed they hover right about 480-510rpm. LOW, when i increased it to 650 it held at 25psi, just sayin.
So yea 15w-40 Rotella is going in right now. Kept trying to make sure i do everything per the manual standards. Even the manual can be wrong
my only 2 cents would be these things eat a lot of oil thru the pvc system, even with the upgraded valve cover. put a catch can on it if you're not going to use a dexos oil.
you can run just about any oil you want thru these as long as you change it before it breaks down. you just gotta worry about degrading o2 sensors and cats long term.
ChevySSR
TYF Newbie
i went back to 5w30 mobile1 for the winter, I noticed absolutely no change in oil pressure after the oil change. I am monitoring the oil consumption closely, but so far has not seen any.
2014 Escalade, 168,000 MI, no trace of oil in the intake. No catch can either.
2003 Hummer 6.0 liter, went through the motor couple months ago. Updated valve cover. It did need new valve guides and seals when going through the head. 5,000 miles on it since rebuild, also no oil in the intake. Neither vehicle uses a drop of oil between changes at 4,000 miles. (The Hummer used to put a lot of oil into the intake. Went through the motor to 112,000 miles.)
2003 Hummer 6.0 liter, went through the motor couple months ago. Updated valve cover. It did need new valve guides and seals when going through the head. 5,000 miles on it since rebuild, also no oil in the intake. Neither vehicle uses a drop of oil between changes at 4,000 miles. (The Hummer used to put a lot of oil into the intake. Went through the motor to 112,000 miles.)
The number one cause is worn valve guides and valve seals, right there under the valve cover. I usually go through my LS cylinder heads around 75,000 miles. I view it as a regular maintenance item. Granted, no doubt the heads would continue going for another 250,000 miles... I just personally have zero tolerance for any oil leaks, seepage or excess blow by.
Call it OCD... But there's nothing better than a fresh set of heads
Call it OCD... But there's nothing better than a fresh set of heads
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