Mixed 5w30 with 0w20

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PontiacHO

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2017 GM 5.3 (37k) thats supposed to have 0w20. Noticed this past weekend a tapping noise on cold start up. 5k since last oil change and OLM reading 25%. Changed oil today using what I had on hand. 5 qts Valvoline Advanced 0w20 and 3 qts Quaker State Ultimate Durability 5w30. PF63E oil filter. Interested to see if this "blend" may make it less noisy. It's already in the low 90s here so probably would have been better off with a full 8 qts of 5w30. We'll see.
 
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Originally Posted by CT8
Viscosity clash.


What would viscosity clash look like between a 0-20 and a 5-30 look like? What issues would that cause?
 
This thread is really shaping up. Viscosity clash? Sometimes it is very difficult to determine if someone is really serious (but lost) or they just say things to get attention.

Notice that there is no question here, nor a request for any diagnosis or determination of whether the 5W-30 grade did any harm.
 
Had a 68 Firebird HO 350 back in the mid-seventies. WRAPPED it around a red oak. Still feel like a fool 45 years later....
 
Originally Posted by kschachn
This thread is really shaping up. Viscosity clash? Sometimes it is very difficult to determine if someone is really serious (but lost) or they just say things to get attention.

Notice that there is no question here, nor a request for any diagnosis or determination of whether the 5W-30 grade did any harm.


I know there's no harm done regarding the blended oils. Just wondering if the added viscosity may quiet what sounded like forged piston noise (cold start). Keep in mind the noise was heard prior to this blended oil change.

Will know in the morning.
 
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Originally Posted by PontiacHO
2017 GM 5.3 (37k) thats supposed to have 0w20. Noticed this past weekend a tapping noise on cold start up. 5k since last oil change and OLM reading 25%. Changed oil today using what I had on hand. 5 qts Valvoline Advanced 0w20 and 3 qts Quaker State Ultimate Durability 5w30. PF63E oil filter. Interested to see if this "blend" may make it less noisy. It's already in the low 90s here so probably would have been better off with a full 8 qts of 5w30. We'll see.

Odds are, it was the oil filter barking at cold startup and you eliminated the noise with this new oil change.
There won't be a clash mixing your 0w20 and 5w30. If the noise persists early-on, you may investigate the lifters or piston slap.
 
I mixed 20w20 with 10w40 on a '53 Studebaker back in the mid sixties. Caused the carburetor nilds to rotate 90 degrees causing a rich mix which welded my intake valves to the eprocanator. Had to tow it three hundred miles to the last remaining Studebaker-Packard dealer.
 
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I am on my third truck with the 5.3s. They can create a little noise on startup.

Its not broken.......
 
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Originally Posted by A_Harman
Originally Posted by CT8
Viscosity clash.


Oh, Puhhhhhh-leaze!



Extremely sure CT8 was just joking around here
lol.gif
 
Also the oil pumps rattle on startup as they "bounce" between high and low pressure on startup.

I believe their was a TSB on startup noise from the oil pump which was declared normal/acceptable.
 
Originally Posted by TheLawnRanger
2.5w25?

Not sure if you're being facetious, but no such thing. It's either a 20 or a 30. Or 0W/5W. Heck - I remember discussions with an engine testing engineer about some weird additive reactions where two different 5W-30 motor oils blended together rated as a 5W-40, or something to that effect.
 
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