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VF 6.2L - calling oil & engine gurus!

vombil

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OP, oil - stick to factory spec - always.

engine, if you believe there is an issue GM need to be given the opportunity to diagnose and remedy - if you are dissatisfied you need to tell them first and from there you will need at least one independent party corroborate anything and that party is not a noise you heard on Youtube, it is a full and proper mechanical report.

all LS engines are noisy in some way, tickety tack. Don't be surprised if they say it's normal.
yeh they've already tried that with previous LS3's - i think that say 'within spec'or some crappy throw away line like that.
 
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vombil

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Got no input on your issue, but the '5w' in those oils are their cold viscosity, so there's no difference in terms of oil grades between those two when cold (apart from the obvious brand/type/quality etc...) so you haven't changed anything, and 60 seconds is definitely not enough to get it up to a temp where it would make a difference.

You should really try a 10w30 or 10w40 (10w whatever, the important part here is the 10w instead of there being a 5w). Seen a couple of posts here of people running the Castrol Supercar 10w60 stuff in their later LSs and said it eliminated engine chatter at every point. I've run a 10w50 in every car I've owned, ones that want 10w30, even with VCT or VVT or new or old and wouldn't hesitate to try it on an LS3 if I owned one. I'd even try a 15w/x to see if it made a difference, at least in the short term if that did nothing, particularly in the summer. At some point though there is something wrong if using stupidly thick oil (like 15w or 20w+ on an engine that's recommended for 5w) is the only way to get it quiet.

Have a look at the charts below, left hand side of those curves is the starting temp. Second chart is with the same hot temp viscosity (40 weight) but different cold viscosities (5w, 10w, and 15w). The oil will be thicker when cold and thins out as it heats up which is why they approach each other and group together when reaching operating temp. It's why it's not as much of an issue to run a 10w50 in a car that recommends 10w30/40.
View attachment 218619 View attachment 218620
cheers dude. I did try a 10/40 which did not achieve anything. Theres no doubt in my mind the 5/30 semi is thicker as any 5/30 syth has never ever made my engine produce such a deep noise that was so long lasting. I'm thinking of going a 0/40 or 5/40 full syth for my next attempt

off topic but I put 25/70 into an ecotec V6 today with the view it might kill off some balance shaft noise - and it near on seized. the noise would have made your skin crawl!

Personally I feel there are major major viscosity difference between synthetic and mineral oils of the same claimed weights. All you need to do is pick up a bottle of castrol edge 5/30 and then grab a penrite semi syth 5/30 or even a full mineral 5/30 if you can find one and shake the bottles... the castrol feels like milk inside and the mineral feels a bit like a milkshake. They genuinely have a physically different consistency and I have no doubt that the engine responds accordingly.
 

vombil

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Got no input on your issue, but the '5w' in those oils are their cold viscosity, so there's no difference in terms of oil grades between those two when cold (apart from the obvious brand/type/quality etc...) so you haven't changed anything, and 60 seconds is definitely not enough to get it up to a temp where it would make a difference.

You should really try a 10w30 or 10w40 (10w whatever, the important part here is the 10w instead of there being a 5w). Seen a couple of posts here of people running the Castrol Supercar 10w60 stuff in their later LSs and said it eliminated engine chatter at every point. I've run a 10w50 in every car I've owned, ones that want 10w30, even with VCT or VVT or new or old and wouldn't hesitate to try it on an LS3 if I owned one. I'd even try a 15w/x to see if it made a difference, at least in the short term if that did nothing, particularly in the summer. At some point though there is something wrong if using stupidly thick oil (like 15w or 20w+ on an engine that's recommended for 5w) is the only way to get it quiet.

Have a look at the charts below, left hand side of those curves is the starting temp. Second chart is with the same hot temp viscosity (40 weight) but different cold viscosities (5w, 10w, and 15w). The oil will be thicker when cold and thins out as it heats up which is why they approach each other and group together when reaching operating temp. It's why it's not as much of an issue to run a 10w50 in a car that recommends 10w30/40.
View attachment 218619 View attachment 218620
check the graph - 5 weight Vs 20 weight. It's suppose to be 4x the cold weight ie 20 is 4x heavier than 5 but the graph suggests the 20 is only 3x as thick as the 5. plot thickens - nice pun btw
 
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Ron Burgundy

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yeh thanks mate. what mileage had yours done when it started and did you have to take them to court? I have video of mine. noise lasts longer with magnatec 5/30 but is not nearly as loud as the semi syth. seems to be ok so far in terms of the detonation/slap when driving
Mine did it from new...
No court action
 

vombil

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Mine did it from new...
No court action
did you get the existing motor rebuilt or replaced? Is there any reference I could give the service manager to add weight to my arguement - like if he searched your rego he could get the history of your claim or does it not matter at all? I'd just like to be able to say 'look, you have problems with this engine and if you want evidence of the same problem with you settling on a rebuild, here is the rego"
 

mpower

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did you get the existing motor rebuilt or replaced? Is there any reference I could give the service manager to add weight to my arguement - like if he searched your rego he could get the history of your claim or does it not matter at all? I'd just like to be able to say 'look, you have problems with this engine and if you want evidence of the same problem with you settling on a rebuild, here is the rego"

you could reference this


As I mentioned earlier you need an engineer to confirm your issue and do a report.
 

Ron Burgundy

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did you get the existing motor rebuilt or replaced? Is there any reference I could give the service manager to add weight to my arguement - like if he searched your rego he could get the history of your claim or does it not matter at all? I'd just like to be able to say 'look, you have problems with this engine and if you want evidence of the same problem with you settling on a rebuild, here is the rego"

All info here

Don't tell them about 'experiments' with oil....or they will blame you...

https://forums.justcommodores.com.a...ton-slap-engine-replaced.267349/#post-2925112
 

mpower

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i posted this in another thread when referencing oil viscosity.

let an engineer remind you of why you use the recommended and nothing else.

 

_R_J_K_

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check the graph - 5 weight Vs 20 weight. It's suppose to be 4x the cold weight ie 20 is 4x heavier than 5 but the graph suggests the 20 is only 3x as thick as the 5. plot thickens - nice pun btw

Pretty sure the measurement they use is a log function/equation and not linear, in the same way that decibels don't go up in a linear way. Guess you'd have to ask Penrite though, that's where I found them.
 

mpower

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Pretty sure the measurement they use is a log function/equation and not linear, in the same way that decibels don't go up in a linear way. Guess you'd have to ask Penrite though, that's where I found them.

the video i linked has a good explainer about the base oils and how the cold temp is determined.
 
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