MaxLife 5w-30 5,200 mi. '97 Silverado 7.4L

[thinbluelinetx]

Al 4
Cr 1
Fe 11
Cu 4
Pb 23
Sn 0
Mo 243
Ni 1
Mn 0
Ag 0
Ti 0
K 10
B 13
Si 11
Na 276
Ca 1911
Mg 10
P 676
Zn 727
Ba 0
Sus viscosity@210F 60.0
cSt viscosity@100C 10.23
Flashpoint in F 390
Fuel %. Antifreeze %. 0
Water %. 0
Insolubles. 0.3
TBN. 2.3

This sample from your Silverado looks good overall. Universal avgs show typical wear levels for the 7.4L V-8 after about 3,300 mi on the oil. This oil had 5,200 mi on it an most of the wear metals compare very well with averages. That's a good sign that the engine is doing pretty well mechanically. It's unusual to see lead as the dominant wear metal. This level shows a little excess wear at the bearings, bit it's just something to watch for now. The TBN was 2.0 showing some active additive left. Try 6,500 miles on the next oil.

 

[YZF_Eric]

Thats a lot of moly

 

[genynnc]

Well done. Thank you for sharing.

 

[addyguy]

Go thicker. In the absence of excessive fuel or silicon, the bearing wear is from an oil that is too thin.

BB Chev's like their oil thick - I'd seriously consider using a 15W-40 or 5W-40 HDEO in this rig. 5W-40 would most likely give you the best all-around balance.

 

[thinbluelinetx]

This truck is driven about 3 or 4 days a week 60 miles round trip to and from work. 80-90% highway miles. At the the time of the oil change it had 137,590 miles.

 

[thinbluelinetx]

That's an interesting point on the thicker oil. I'm just wondering why GM would recommend 5w-30 if it wasn't the ideal oil for the 7.4L.

 

[addyguy]

Fuel economy reasons, that's it. Small-block Chev's run well on thinner, 30-weight oils. Big-blocks are a different beast, a very old-fashioned engine - they run better on thicker oil.

In a really hot Texas summer, 20W-50 wouldn't be out of place in this engine.

 

[Turk]

Originally Posted By: addyguy
Go thicker. In the absence of excessive fuel or silicon, the bearing wear is from an oil that is too thin.

BB Chev's like their oil thick - I'd seriously consider using a 15W-40 or 5W-40 HDEO in this rig. 5W-40 would most likely give you the best all-around balance.


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