Which Synth yields best results in 5.3l GM truck?

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Hi guys,

I have spent days reading through posts. Thanks for all the GREAT info!

My conclusions are that is seems that different oils do better in different applications.

I have a 2003 5.3L Silverado. I'm looking for the best oil for that application. I use the truck as a daily driver on the highway and in the winter I plow driveways (slowly in 4x4 LO).

I always start my vehicles up and rive immediately ~1.5 slow miles (
My thoughts are that a synthetic oil that does not run down to the pan when cold (like dyno oil) would be best for me.

I know poeple on here have not had the best UOA's with Royal Purple, but one of their claims is that the oil remains on parts after the engine cools.

Do all synthetic oils do this?

Thanks!
beatle78
 
I use Amsoil 0w30 in my 94 GMC 1/2 ton 4wd 5.7L and it seems to work great. Truck has 309k on engine. Shaeffers 5w30 synth is a good choice also. I have tried Mobil 1, but it always seems to make the FE track higher in the uoa. I have used PP and like it as well. In order of preference:

1 - Schaeffers 5w30 synth with 7k drain interval
2 - Amsoil 0w30 with 9k drain interval
3 - Penzoil Platinum 5w30 with 6k drain interval
4 - Supertech 5w30 with 4-5k drain interval

I have never used Royal Purple, but since it's harder to get than the above oils, I'll stick with what I can get quick and locally. And actually a film of oil will remain on all engine parts for some time after shutdown with any oil you use, some maybe better than others, but I never have had a problem with the above oils. I even use valvoline dura blend on occasion when I'm slumming it.
 
M1 0w30, will work well in the summer and great this winter,plus
you can get it locally at wal-mart for a good price..my '99 5.7
loves the stuff..
 
I had a 2005 5.3L Silverado and a 2007 NBS Silverado with the 5.3L. I ran both on 5W-30 Royal Purple. The engines loved it. Penzoil Platinum or the new(er) Quaker State Torque Power synthetic would be my second choices.
 
Last edited by a moderator:
Originally Posted By: 03cvpi
I use Amsoil 0w30 in my 94 GMC 1/2 ton 4wd 5.7L and it seems to work great. Truck has 309k on engine.


WOW! over 300K? I love those 5.7L's!

Thanks for sharing your input!
 
Originally Posted By: NHSilverado
I had a 2005 5.3L Silverado and a 2007 NBS Silverado with the 5.3L. I ran both on 5W-30 Royal Purple. The engines loved it. Penzoil Platinum or the new(er) Quaker State Torque Power synthetic would be my second choices.


NHSilverado, Can you elaborate? What do you mean by the engines "loved it"?

What differences did you notice with the Royal Purple?

Thanks,
beatle78
 
Originally Posted By: beatle78
Originally Posted By: NHSilverado
I had a 2005 5.3L Silverado and a 2007 NBS Silverado with the 5.3L. I ran both on 5W-30 Royal Purple. The engines loved it. Penzoil Platinum or the new(er) Quaker State Torque Power synthetic would be my second choices.


NHSilverado, Can you elaborate? What do you mean by the engines "loved it"?

What differences did you notice with the Royal Purple?

Thanks,
beatle78


Smoother idle and acceleration, less engine noise overall but especially at cold startup which is an issue for GM 5.3L's( especially older ones like yours ), and a slight MPG improvement( approc .2-.5 MPG city and highway ).
 
Last edited by a moderator:
Originally Posted By: beatle78
Originally Posted By: 03cvpi
I use Amsoil 0w30 in my 94 GMC 1/2 ton 4wd 5.7L and it seems to work great. Truck has 309k on engine.


WOW! over 300K? I love those 5.7L's!

Thanks for sharing your input!

My '99 Z71 5.7 has 220,000, uses no oil and still 50 psi(M1 0w30) of oil pressure,and 16 to 20 MPG.. go GM!!!!
 
Originally Posted By: beatle78
Originally Posted By: NHSilverado


NHSilverado, Can you elaborate? What do you mean by the engines "loved it"?

What differences did you notice with the Royal Purple?

Thanks,
beatle78


Smoother idle and acceleration, less engine noise overall but especially at cold startup which is an issue for GM 5.3L's( especially older ones like yours ), and a slight MPG improvement( approc .2-.5 MPG city and highway ).


ok, NICE!

I noticed my truck (which I've owned for ~3 weeks) does have a little bit of a rough idle. It only has 36k miles.

I have read reports about piston slap on cold startups.

Did you gain the .5 mpg highway with just RP motor oil, or with RP tranny and RP diff fluid as well?
 
Originally Posted By: 03cvpi

My '99 Z71 5.7 has 220,000, uses no oil and still 50 psi(M1 0w30) of oil pressure,and 16 to 20 MPG.. go GM!!!!


Those mpg numbers are AWESOME! esp for a 200k mile engine!
 
I use Pennzoil Platinum 5w-30 in my 2005 Sliverado Z71 with the 5.3 & I've been using it for about 2 years or more, I think. I think that it's a great oil & you can usually find it at a good price.
 
Originally Posted By: beatle78
Originally Posted By: 03cvpi

My '99 Z71 5.7 has 220,000, uses no oil and still 50 psi(M1 0w30) of oil pressure,and 16 to 20 MPG.. go GM!!!!


Those mpg numbers are AWESOME! esp for a 200k mile engine!

yes i am pleased,did allot of work to it,full tune up new
o2 sensors/fluids etc, she got the works,runs great..
 
Originally Posted By: panthermike
yeah, those 5.7's are great motors. My buddy just got rid of his 94' with about 290K, original motor and tranny.

I believe it.. my tranny is original too
 
beatle78,

I have the exact same year & engine and have been trying & running different Syn's for 65,000 miles.

The best Syn for it is either the Amsoil or PP (Pennzoil Platinum). The engine sounds great with either of them in it!
thumbsup2.gif
 
Oh yea, since you are talking MPG's, I get 18.5 MPG at 75 MPH and 22-23 MPG at 55-60 on my 5.3L with 129,000 miles on it......
 
Originally Posted By: tpitcher

Oh yea, since you are talking MPG's, I get 18.5 MPG at 75 MPH and 22-23 MPG at 55-60 on my 5.3L with 129,000 miles on it......



I hope you don't drive too much... Ouch.
 
Originally Posted By: tpitcher
beatle78,

I have the exact same year & engine and have been trying & running different Syn's for 65,000 miles.

The best Syn for it is either the Amsoil or PP (Pennzoil Platinum). The engine sounds great with either of them in it!
thumbsup2.gif



tpitcher,

Would you say Amsoil is worth the extra cost over the PP? If so, what added benefits do you get from it?

18.5 mpg's is GREAT! Have you always gotten that? What other mods have you done? What tires and pressure do you run?

My first 2 tanks yielded ~17.5 mpg's. That cruise set at 75mph as well. No mods yet.

I have the stock Bridgestone Dueller 693's 265/75/R16.

Thanks!
beatle78
 
Last edited:
Originally Posted By: beatle78
Originally Posted By: beatle78
Originally Posted By: NHSilverado


NHSilverado, Can you elaborate? What do you mean by the engines "loved it"?

What differences did you notice with the Royal Purple?

Thanks,
beatle78


Smoother idle and acceleration, less engine noise overall but especially at cold startup which is an issue for GM 5.3L's( especially older ones like yours ), and a slight MPG improvement( approc .2-.5 MPG city and highway ).


ok, NICE!

I noticed my truck (which I've owned for ~3 weeks) does have a little bit of a rough idle. It only has 36k miles.

I have read reports about piston slap on cold startups.

Did you gain the .5 mpg highway with just RP motor oil, or with RP tranny and RP diff fluid as well?


The gains I mentioned were based soley on the oil as that is what you asked about. I did swap both Silverado's over to RP's gear oil as welll( MaxGear 75W-90 in both front and rear dif's on both trucks ). That bumped the MPG higher( over 1 MPG highway gain ). Never used the RP MaxATf in the trucks although I have used it before and it is great stuff.

If you have a rough idle now the oil isn't going to fix it. It just smoothes out a standard idle further.
 
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