Oil swap to help with piston slap?

c good

Original poster
Member
Dec 8, 2011
526
My last oil change I swapped from 5w/30 Valvoline Synthetic Blend to the full Synthetic Mobil One 5w/30. Since the swap I have noticed more piston slap noise when cold. It goes away when warmed up.

It does seem more noticeable since going with the Mobil One. Would it hurt anything to go back to the Valvoline Syn Blend? Is the start up piston slap anything to really worry about?

All my research says no but it is annoying and unnerving at first. I just can't help but think that slap will get worse with every cold start up. So...that's why I'm thinking of going back to the Valvoline and maybe even upping the viscosity to 10w/30. I'm in S.California so don't need to worry about cold temps affecting oil. Thanks for any input.
 

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,642
Tampa Bay Area
Suggested Maintenance (and reasoning behind this approach) is covered in these two prior Threads:

https://gmtnation.com/forums/threads/a-c-delco-foaming-top-end-cleaner.22535/

https://gmtnation.com/forums/threads/carbon-cleaning-the-4-2l-ll8-experiment.21693/

Piston Slap is MUCH more evident in Cold Climes and Winter Weather for THESE Reasons. Suggest switching to a THINNER Lower Viscosity Number Mobil1 OW-30 Weight Motor Oil for quieting down Piston Slap as follows:

From IMSTRICKEN06... His dramatic advice is NOT to go to a 10W-30 Weight Oil...You'll be heading in the WRONG Direction:

 
  • Like
Reactions: Redbeard

c good

Original poster
Member
Dec 8, 2011
526
That makes sense about going with the lighter oil. I think I'm going to to the top end soak with the AC Delco T.E.C. They make it in aerosol and liquid. What does everyone think would be better? I'm figuring the liquid per the instructions in the links above but just curious. Thanks All....Envoy still running good after the 11 year long PCM nightmare! :smile:
 

Mektek

Member
May 2, 2017
656
FL
manual shows 5w30 is good for well below freezing. The piston slap in the I6 is a design issue that thinner oil won't help. Maybe if you're in Alaska the 0w would be a good idea - that would be a case of frozen engine noise, not just cold.
I would speculate that the mobil 1 and valvoline do not perform exactly the same even though they have the same 5w30 rating.....
 

NJTB

Member
Aug 27, 2012
612
Flemington, NJ
I did the same thing. Regular synthetic Mobil 1 5-30 seemed to make the engine noises worse.
Switched to Mobile 1 hi milage synthetic and the noises got noticeably better. Use it all the time now.
 

cornchip

Member
Jan 6, 2013
637
My last oil change I swapped from 5w/30 Valvoline Synthetic Blend to the full Synthetic Mobil One 5w/30. Since the swap I have noticed more piston slap noise when cold. It goes away when warmed up.

It does seem more noticeable since going with the Mobil One. Would it hurt anything to go back to the Valvoline Syn Blend? Is the start up piston slap anything to really worry about?

All my research says no but it is annoying and unnerving at first. I just can't help but think that slap will get worse with every cold start up. So...that's why I'm thinking of going back to the Valvoline and maybe even upping the viscosity to 10w/30. I'm in S.California so don't need to worry about cold temps affecting oil. Thanks for any input.

What kind of mileage does this engine have on it?
 

vipergg

Member
Dec 7, 2011
191
I once switched to Mobil 1 on a chrysler V6 engine and the thing sounded like a diesel when i started it. Couldnt wait to get that oil out of it and go back . That did fix it after I switched back to normal oil .
 

aaserv

Member
Dec 1, 2019
408
N of Baton Rouge, La.
I never recommend switching oils on high mileage vehicles. Valvoline is top shelf oil and you've had it in there all this time I wouldnt switch. Different manufactures use different additive packages in their oils and switching can lead to leak probs in my experience. Last year I went against my own rule and switched from Mobile1 to the new Shell Synthetic in my 4.8L. Already had to replace the front seal and now the valve covers are pouring. Never leaked a drop in the 1st 300K miles.
These I-6 motors get noisy with age. Just a fact. If its not lifters its timing chains or piston slap. Keep that oil changed and drive it like you stole it. Turn the radio up and you wont hear the noises :hopeless::hopeless:
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,047
Brighton, CO
You ain't heard piston slap until you hear my 5.3 in my Envoy. Been meaning to get a video of it ..
 

Forum Statistics

Threads
23,273
Posts
637,499
Members
18,472
Latest member
MissCrutcher

Members Online