5W30 or 10W30?

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Hi guys!

I'm currently running Valvoline 5W30 All-Climate along with a bottle of Synpower oil treatment. This is on a '98 Blazer with 51K miles. Should I continue with this or switch to 10W30? Would there be any benefit? Also, would it be wise to switch to synthetic or semi-synthtic at this point? Right now my OCI is 3 months/3K miles. I'd like to extend this also.
 
How's the weather?
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In Florida, there is no reason or need to run 5w-30. I'd stick with 10w-30 for your climate.
 
If you'd like to extend the OCI, either UOA the oil you are using, or switch to a quality synthetic.

Since you're in Florida, I'm guessing that you really don't need a 0w,5w,... oil. You don't have the excessively harsh winters like we do. You might even be better off with the 40wt oils.
 
I have a 96 GMC pickup with the same motor as your Blazer, 4.3L V-6. I have run Mobil 1 10w-30 in it for 105000 miles and it still runs great. I would use the 10W-30. I little extra protection for those hot summer days. As it does'nt get that cold in Texas in the winter I also run the 10w-30 in the winter time also with no ill effects.
 
Thanks for the replies.

So far we are in pretty good shape as far as weather. But the storm is headed our way
shocked.gif


So if I run Mobil 1 10W30, I can extend the OCI? What about Valvoline Synpower or DuraBlend?

I have never done a UOA before, never thought about it since I have pretty much stayed with the 3 months/3K routine. Recently I realised I was wasting money by changing synthetic that often
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That's why I'd gone back to dino.
 
quote:

Originally posted by Chevynut67:
Hi guys!

I'm currently running Valvoline 5W30 All-Climate along with a bottle of Synpower oil treatment. This is on a '98 Blazer with 51K miles. Should I continue with this or switch to 10W30? Would there be any benefit? Also, would it be wise to switch to synthetic or semi-synthtic at this point? Right now my OCI is 3 months/3K miles. I'd like to extend this also.


A service writer at the local Chevy dealer made it quite clear that in his not-so-humble-opnion, if GM recommends 5w-30, then that is what to run. He explained that there is more to it than ambient temperature, such as bearing clearances, etc.

In both my 98 Silverado (5.7L V8) and my Avalanche (5.3L V8), the book calls for 5w-30, and that 10w-30 can be used if the former cannot be found.

Patman has suggested that 10w-30 is really becoming obsolete, given the specs of 5w-30. After considering this at length and looking at various specs, I am inclined to follow his lead.

If one looks at many of the oils, you can see that there is little additional wear protection offered by a 10w-30 oil to its 5w-30 counterparts (exceptions exist, true, I posted one - Syntec 5w-30 seems to have a marginal HT/HS value).

I ran GTX in my 98, but plan to run Kendall GT-1 synthetic in the new truck (I guess I like the "GT" lingo....). However, I do plan on running 3K OCI, as it seems like oil is cheap whereas new cars are not.

Bob W.
 
There seem to be two trends at work here (in dino oils, at least).

First, many 5w30 dinos, especially the "energy conserving" oils, seem to shear down to a 20wt within a couple thousand miles. While it could be argued that this is because 5w30's require more vii's and that they don't offer the protection of 10w30's, it's starting to look like they are designed to shear down to 20wt, thus the "energy conserving" status.

Second, manufacturers (ConocoPhillips for example) are upgrading the add packs and basestocks of SL/SM 5w20 and 5w30 dinos, while leaving 10w30 et al. relatively unchanged. (OK, this isn't entirely true in CP's case. They will upgrade 10w30 next Spring.)

So to paint with broad strokes, if you're a stickler for a "true" 30wt. multivis dino oil, 10w30 may be it. If you want the "latest and greatest," the 5w20's and 5w30's are looking like the best choice.

I'd run a 10w30 in Florida myself. But we'll see what the new Mystik JT-8 and Phillips TropArtic 5w30 blends look like
smile.gif


mr
 
I'll have to dig out some of my newer books but I don't buy in to the clearance thing at all.

1971 350 Chevy crank and rod.
.0008-.0020 and .0013-..0035

1985 350 Chevy crank and rod.
.0008-.0020 and .0013-.0035

Both have a rod side clearance of .006-.014
 
quote:

Originally posted by KW:
I'll have to dig out some of my newer books but I don't buy in to the clearance thing at all.

1971 350 Chevy crank and rod.
.0008-.0020 and .0013-..0035

1985 350 Chevy crank and rod.
.0008-.0020 and .0013-.0035

Both have a rod side clearance of .006-.014


I don't buy it either. Unless they've gone to more exotic materials or changed the sizes of the parts drasticly the clearances shouldn't be that different...
 
quote:

Originally posted by KW:
I'll have to dig out some of my newer books but I don't buy in to the clearance thing at all.

1971 350 Chevy crank and rod.
.0008-.0020 and .0013-..0035

1985 350 Chevy crank and rod.
.0008-.0020 and .0013-.0035

Both have a rod side clearance of .006-.014


The vehicles I am referring to are from 1998 and 2004.

It would make for interesting dicsussion to know the crank and rod clearances for the newer engines, as well as camshaft bearing clearances.

Bob W.
 
Add my datapoint to the report response from 2004 F150 4x4. I have a 4.3 V6 in a 95 S15. It has 100,500 miles on M1 10W-30 with 6,000 miles OCI is doing good.

I live in near Sacramento CA so summers are hotter here and winters cooler on average than yours. Wind speed are a lot lower here though, I hope you and your family and posessions are all OK.
 
350 chevy motors were designed in the 50's and pretty much kept the same specs into the early 90's. These engines will run forever if properly maintained. I think the main concern is if you have a overhead cam, you need better flow upon startup. I dont really buy the tighter tolerances of newer motors. Oil clearance is oil clearance. My wife has a 2000 Dodge intrepid with the 2.7L V6. Very hightech engine that if it had 8 cylinders it would be larger than my 460 Ford! 4 overhead cams and all aluminum block. 5w30 is what this engine gets all year round. I have been changing the oil every 2500 miles just to keep this sludge monster clean.
 
Originally posted by XS650:

I hope you and your family and posessions are all OK.

Thanks for your concern. We are doing well. Didn't get hardly any damage. Just was out of power for a few hours. Don't know about Ivan though.
 
quote:

Originally posted by jsharp:

quote:

Originally posted by KW:
I'll have to dig out some of my newer books but I don't buy in to the clearance thing at all.

1971 350 Chevy crank and rod.
.0008-.0020 and .0013-..0035

1985 350 Chevy crank and rod.
.0008-.0020 and .0013-.0035

0.


I don't buy it either. Unless they've gone to more exotic materials or changed the sizes of the parts drasticly the clearances shouldn't be that different...


Your instincts serve you well on main bearings and not so badly on rod big ends.


Here's a couple more data points from factory shop manuals. If I had given clearances as (inch clearance/inch bearing diameter), the results might have been even closer. But the manuals are put away now.

2000 Acura 3.2L V6 crank and rod (inches)
0.0008 - 0.0017 (1) and 0.0008 - 0.0017

1996 Chevy 5.7L V8 LT-4 crank and rod (inches)
0.0009 - 0.0024 and 0.0013 - 0.0035

Note (1) Bearings 2,3,4

On the mains, all three Chevys and the Acura are all pretty close at tightest clearance. The Acura isn't as loose on the loose end. That's because Acura holds their manufactuing tolerances closer. If you asked the 1971 GM engineers what they really would have liked to use for main bearing clearances on the loose end of the tolerance range, I'll bet they would give you numbers closer to Acura's than GM's.

As far as the range of main bearing clearances goes, the 1971 Chevy oil has to handle clearances just as small at the newer Acura's oil.

Con rod big end clearances are another story. All three Chevys are the same at 0.0013 to 0.0035, a range of 0.0022 from tight to loose.

The total tight to loose range on the Acura is 0.0009. Only 41% of the Chevy's tolerance range. Looks like Acura sees a reason to hold those clearances a lot closer than Chevy and is willing to pay for the extra manufacturing control.

We could ponder why Chevy held their crank tolerances in 1971 almost as well as Acura did in 2000, yet let their rid big end tolerances go all the h3ll compared to a more modern engine.

One other little factoid to toss into the fray that not everyone is aware of....

Within reasonable real world limits, the bigger the static bearing clearance, the smaller the running bearing clearance on the loaded side of the bearing.
 
Chevynut67 you can go to 5k oci with the Mobil 1. I did it ever 3k up to 80000miles on my truck until I realized I was just throwing my money away. I disagee very strongly with the idea that 10w-30 motor oil will be "obosolete" soon !!! Glad ya'll came thru the storm ok.....Dave
 
As a person who spends a lot of time driving in FLA, here are my concerns about viscosity:
Say you are using this 5w30 in 90F air temps and it has sheared down to a 20w.
Now at the same time your AC compressor and or water pump start to fail, and the engine is running super hot so your temp alarm goes off, the only thing that can stop engine seizure or valve warpage is the oil films---which multigrade would you choose then?
 
quote:

Originally posted by Lubricious:
Now at the same time your AC compressor and or water pump start to fail, and the engine is running super hot so your temp alarm goes off, the only thing that can stop engine seizure or valve warpage is the oil films---which multigrade would you choose then?

If I expected this to happen I think I would want Redline Oil in my crankcase.

What grades are listed in your owner's manual? That is always a good place to start. I do feel that a 10wXX is the way to go, probably a 10w30. How is your oil pressure? If running a bit low, you might be able to step up to a 10w40.

Better than the All Climate and Synpower Oil Treatment would be straight Durablend IMO.
 
quote:

Originally posted by Chevynut67:
I'm going to switch to Durablend 10W30 on my Blazer. Durablend should also be fine to use on the wife's '04 Malibu, right? I'm going by the OLM on it at this point.

First check out this confusing mess I just posted:
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=008007
Then I would say, can the Blazer run 10w40? Might be the better Durablend deal. Oh, but the 10w30 is probably OK, but for 10w30 you might do better with Valvoline Maxlife as it has 12-22 percent PAO.
 
Just wanted to give you a perspective of an engine that has both speced 5w-30 and 5w-20, from the 2002 Ford 4.2L V6 shop manual:

Main Bearing Clearance to Crankshaft
Desired 0.001-0.0014 in
Allowable 0.0005-0.0023 in

Rod Bearing Clearance to Crankshaft
Desired 0.001-0.0014 in
Allowable 0.00086-0.0027 in
 
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