Generation 1 Vortec 5.7 350 V8......

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How hard is this engine on oil? I have one with 100,000 miles and I'm thinking about starting it on synthetic(GC). I'm wondering if this engine might be easy on oil? It has a 5qt sump. Thank you!
 
My 95 4.3L Vortec V6 with 101k miles is essentially 3/4 of a 5.7L Vortec V8.

My impression is that it isn't particularly hard or easy on the oil. Using M1 10W-30 with 6k mile OCI, the engine isn't as clean as some vehicles I have that get the same treatment, but it isn't cruddy either. The oil looks and feels OK at 6k miles. Dark but not black or burnt. It burns less than 1/2 qt in 6k miles.
 
quote:

Originally posted by Chris B.:
How hard is this engine on oil? I have one with 100,000 miles and I'm thinking about starting it on synthetic(GC). I'm wondering if this engine might be easy on oil? It has a 5qt sump. Thank you!

I am not sure what "generation 1" means, but I had a 98 Silverado with this engine and I ran GTX 10w-30 for the life of the vehicle. The engine always ran very well, and used about 1/4 to 1/2 quart between changes (3K miles).

I sold it at 135K miles and it had previously passed the SMOG II test as an ultra low emissions vehicle, so I assume the engine was still in good shape.

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Bob W.
 
Generation 1 means that this was the 1st series of GM engines to be set up as "Vortec's". IIRC 1996 was the 1st year the 350 was a Vortec engine rather then a basic 350.

Mine also has been raised on GTX and runs well and smooth. I'd like to go Synthetic for the extra protection. I want to get 250-300,000 out of it! I think it can be done as I have read about these engine going farther in a lot of cases and have seen it first hand.
 
The LT1 350 in my old 95 Firebird is very similar to the engine in your truck, and it did very well on GC. The small block Chevy likes a thick 30 to thin 40wt oil a lot.

You should have no problem getting 300k out of this engine with proper maintenance.
 
My 3/4 350 (4.3L) runs great, and will rack-up some high miles without complaint, but the truck around it is falling apart!
 
quote:

Originally posted by XS650:
My 95 4.3L Vortec V6 with 101k miles is essentially 3/4 of a 5.7L Vortec V8.

My impression is that it isn't particularly hard or easy on the oil. Using M1 10W-30 with 6k mile OCI, the engine isn't as clean as some vehicles I have that get the same treatment, but it isn't cruddy either. The oil looks and feels OK at 6k miles. Dark but not black or burnt. It burns less than 1/2 qt in 6k miles.


I too own a 1995 4.3L CPI Vortec and they are really tough engines.

I would change to synthetic ONLY after performainf an engine flush with a new filter for 30minutes.

After that, you are good to go. Swap in the synthetic (PAO, not GRP III), install a good , non fram filter and enjoy.
 
The old '88 Chev 5.7 was running well at 200K when I sold it a few years ago. Ran it on dino with a 5K OCI. These engines seem to do best on 10w30, even in the summer. I never tried syn, but I imagine it would do well and make sense if one put alot of miles on his rig. I run dino (Pennzoil) in my current '95 5.7 Silverado as I mostly just drive it in the summer with a 3000# truck camper. The 10w30 works great; much better than either 5w30 or 10w40.
 
If I didn't have leaky valve seals (that I'm too lazy to replace), I'd run:

GC 0w-30
M1 0w-40
M1 T&S 5w-40
Rotella T 5w-40

...with an AcDelco filter.
 
With the exception of the head and intake manifold designs, the roller lifters, and the one piece rear main seal, the design of this engine is the same as the original Chevy V/8 from 1955.

My 1986 example of this engine is at 190K and running fine, even though under a previous owner it overheated to the point of carbonizing the oil at least once. One that was somewhat cared for should do at least 250-300K.
 
I have a 98 vortec 350. I have posted UOA's with RP 5w30, and GC. In a couple of weeks, I will post a UOA on redline. Do a search in the UOA section.
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They are not hard on oil at all from a mechanical standpoint. They have gasket problems and emission system problems that can cause the oil to go south quickly! Stay on top of those issues and you will be fine. I would recomend that you run some Auto-RX through that engine though!
 
My brother has a 95 GMC 1500 w/ a 5.7. He started using castrol 10w-30 synthetic @ 115,000 miles and now has about 225,000 miles. No oil use, runs very good but not much power. Those 95's were weal as I understand (non Vortec). I think they were like 210 hp to start. Nice truck though
 
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