Oil for old Chevy TBI 350

Messages
145
Location
Idaho
Thread starter
A few weeks back the MIL got nailed by an uninsured driver. Money is tight for her, so we had to find a replacement vehicle on the cheap. Found a '92 Suburban with 250,000mi. on the clock for (very) cheap. Lots of miles but this thing purrs like a kitten and shifts surprisingly smooth, completely free of rust. Engine and trans was replaced at one point in its life, according to the PO, but of course no paperwork, so who knows. So my question for any of you TBI owners out there is what oil to run? If there were no sales on full syn. I would lean toward running QSHM or SuperTech HM in this beast. But, my go to right now would be 5w or 10w30 Mobil1 HM based on the coupons and rebates available for it right now. Anything wrong with running Mobil1 HM oil in this old rig? I know the TBIs usually came with flat tappet lifters - is there another oil more suitable for that, or does it matter? I've owned several TBIs in the past but it's been years ago. It seems these do as well on conventional as anything, but these days just about everything is a syn blend, even conventionals. Thanks in advance! - Here she is: [Linked Image]
 
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Messages
1,196
Location
San Antonio, TX
That would be getting 10W-40 if it were mine. I'm basing that opinion off the UOA section here at BITOG. Those GM truck V8s have the lowest wear numbers with 10W-40 Castrol GTX or Chevron Supreme.
 
Messages
145
Location
Idaho
Thread starter
I should mention that the Mother-in-law will park this under a car port, so cold winter starts are a reality. In the winter it will usually cool to 15-25 degrees at night, and the dead of winter is commonly sub-zero temps here in the Rocky Mountains.
 
Messages
1,315
Location
NY
The tbi systems are very reliable and simple. I would run a 40wt or 30wt. I don't suspect she will be running it hard or pulling a trailer. Looks like it needs new headlights.
 
Messages
7,054
Location
The Midwest
Run a 0W40 full saps oil meant for German vehicles. It will have more zinc, provide faster lubrication when could, a benefit for flat tappet engines and will be nice and thick as a 40W when warmed up.
 

CT8

Messages
15,408
Location
Idaho
Originally Posted by dave1251
Any 30 or 40 grade of your choice with current API certifications and sleep well.
+1
 
Messages
1,050
Location
NC
Got a 1995 Tahoe, last year of TBI. Mine runs very well on 10w30s, 10w40s, and 5w40. 12mpg city, 15mpg highway. Love it. No regrets.
 
Messages
13,196
Location
Maricopa Arizona
Originally Posted by skyactiv
Run a 0W40 full saps oil meant for German vehicles. It will have more zinc, provide faster lubrication when could, a benefit for flat tappet engines and will be nice and thick as a 40W when warmed up.
You really don't know what your talking about.
 
Messages
10,426
Location
Cincinnati, OH, USA
I had a '94 TBI 350 Sub for a while, I ran from 5W30 up to 20W50 (summer) in it-I would run the recommended 5W30 UNLESS you have low hot idle oil pressure (as mine did)-then move up to 10W40, 15W40, or even 20W50 in hot summer weather to get the oil pressure up-I even used STP Oil Treatment in mine with 20W50, and it started easily down to 0F!
 
Messages
647
Location
ohio
I run PYB 5w-30, VWB 5w-30 or any name brand Synthetic 5w-30 (when it is on sale) in my GM work trucks small block Chevy engines with TBi. Whenever I have done any valve cover gasket or manifold gasket repairs on any of these engines, the internal parts do no have any varnish on them. These engines also do not burn any oil. I run my oil changes 5000-6000 miles.
 
Messages
10,426
Location
Cincinnati, OH, USA
Originally Posted by xtell
I run PYB 5w-30, VWB 5w-30 or any name brand Synthetic 5w-30 (when it is on sale) in my GM work trucks small block Chevy engines with TBi. Whenever I have done any valve cover gasket or manifold gasket repairs on any of these engines, the internal parts do no have any varnish on them. These engines also do not burn any oil. I run my oil changes 5000-6000 miles.
I agree-PYB would be an excellent, low cost choice for a TBI 350, as would Chevron Supreme-both are LOADED with moly!
 
Messages
681
Location
New Hampshire USA
The 95 GMC in my sig now gets M 5/30. This truck was first purchased in 98 by my son and given to me 6 years ago so it has been in the family all this time, sits outside but gets undercarriage oiled annually and waxed every fall. Point is these are IMO one of the most reliable vehicles made.
 
Messages
541
Location
Alaska and Wisconsin
I'd run that recently mentioned Castrol GTX or Chevron Supreme 10W-30 in the winter. See if that same 10W-30 performs adequately in the summer, and if not move to a 10W-40 or a 15W-40 in the summer. Hope she enjoys the big rig.
 
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