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2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by kevm14
I don't understand the cam/crank correlation code thing.
The only thing I can think of is that the thinner oils failed to produce sufficient pressure to activate the VVT actuators in correlation with the crank shaft position. But would that cause catastrophic engine damage requiring engine replacement? Apparently so on those specific engines.
No it wouldn't but it could be that the screens clog throwing off VVT operation. And maybe that's how GM determines that there is enough junk in the oil system to trash the rod bearings...
Thanks to JR for bringing up this new video.
GM is now recalling 6.2 GDI V8 engines to prevent bearing failures directly caused by 0w20 oil.
hot vs. cold viscosity chart shown by LSJr.
LSJr. covers a lot of oiling topics related to engine oil viscosity.
One of the interesting aspect is high load at low Rpm with stock setup (MOD-0: 0W40) guarantees wear from weak bearings film.
In the similar (GDI + low pressure solenoid) stock condition GM proves that chemical friction modifiers can not handle the load alone, viscous film is mandatory.
I wonder how much better GM 0w20 piston sprayers are working on 0w40??
Low pressure solenoid still in use, may be disabled by torque output.
Signature 5W-50-SP PAO inbound (ChrisHimSelf)
+++ "Higher friction" ... caused by oil film
I did hear LSJr. say that "higher viscosity can cause higher temps from more friction..."
I guess that is a good reason not to super-scale into high numbers 20W-60 unless hot engine is tracked. High powered engines are not best for gasoline saving. They require a film!
I find no other way than at least 5W-50 to gain stable spray cooling and ring seal under normal driving conditions. It effectively derates into a 15W-40.
Last edited by CaliBenzDriver; May 3, 2025 at 10:14 PM.
Great investigation and insight on modern oiling. Eric takes us around the core of the 6.2-V8 GM under recalled to stop destruction.
Two discoloured con-rods had spun bearings.
Glitter groved few pistons + bores
Camshaft rollers were contaminated by particulates
Piston grooves were still fair at 50kMi.
Intake valves had moderate burnt oil deposits.
LSJr. would have concluded overall lubrication was satifactory except for bearings under the highest load: hot rods on thin 0W-20 at 3000.Rpm low pressure: FRICTION WELDED!
This engine must have had rod knock, compression loss and high blow-by until bearings welded tight.
+++ UN-EVEN ENGINE WEAR ...
Engine wear shows cylinders contributions were not balanced as other cylinders were hardly working.
Engine does have modern deactivation system which helps super-stress only few cylinders with minimal lubrication (solenoid+ viscosity).
+++ Dual-rate Oil Pump...
Eric shows us the innards of GM's direct-drive vein pump controlled by solenoid. He notes mild wear.
Single camshaft VVT Gear is activate by a PWM oil control solenoid ("magnet") similar to our 4x setup.
This makes cam position eligible for correlation codes due to VVT failure.
+++ Single Step Oil Upgrade:
We note GM goes from w20 to w40 oil in one shot... cam position training does not seem to be a concern.
Last edited by CaliBenzDriver; May 4, 2025 at 12:29 AM.
yes on cold start and today i notice after 60km drive and turned off for 20-30min then it did again but quieter than the initial cold start when car sits for more than 7h
Assuming you were expecting the motul 8100 power to remedy the rattle. Yes?
no i wanted to switch to ester oil that will be better than usual oils and i notice the rattle start not sure if its related to oil since its same W i use usually, so idk what is the reason yet for that
no i wanted to switch to ester oil that will be better than usual oils and i notice the rattle start not sure if its related to oil since its same W i use usually, so idk what is the reason yet for that
This is your first time hearing the rattle?
previously there were no rattle?
This is your first time hearing the rattle?
previously there were no rattle?
i heard the rattle on 1st start of the engine when chain tensioners were changed (preventive) there were no rattles at that time (7k km/5months ago) and last week when oil were changed i hear on first start of engine the rattle and i thought because there's no oil and few days later i decide to open the hood and start the car to see if something weird i will hear and i heard the rattle also that rattle can be heard only if you open the hood and you stay near the engine inside the car you can't hear it
Correct, I’m currently running Motul Xcess Gen2 and it’s been absolute 5star rating of it. Wishing to test this to feel how it is.
I believe SP rating is not available in US. If available, would love to source it.
Only SN
I ran that oil 5/40 xcess gen 2 for four years. I even mistakenly thought it switched to a SP rating in 2024… Loved it. SP is better and higher weight has been better. FWIW. The weight change is anecdotal, though substantiated and the chemistry change is because the manufacturers realized an error in their ways….they were unknowingly recommending to destroy engines in the name of mpg with poor chemistry for gdi engines.
Last edited by Baltistyle; May 4, 2025 at 03:58 PM.
I ran that oil 5/40 xcess gen 2 for four years. I even mistakenly thought it switched to a SP rating in 2024… Loved it. SP is better and higher weight has been better. FWIW. The weight change is anecdotal, though substantiated and the chemistry change is because the manufacturers realized an error in their ways….they were unknowingly recommending to destroy engines in the name of mpg with poor chemistry for gdi engines.
very interesting. It’s confirmed to be SN not sure where people are sourcing SP rated ones but the one I’ve used was SN and I hear no rattle what so ever.
so Balti, what do you recommend and do you currently use?
I ultimately do plan on going over to 5w50. However not as of now.
Simply wishing to hop over to SP. The reason for the Pennzoi Platinum Euro I’ve just received. Only SP rated 5w40 with mb 229.5 approval.
Last edited by E63SAMG2014; May 4, 2025 at 04:21 PM.
I am not sure how the MB Approval process goes but I think most of it is along the lines of: Does it save gas? Yes. Approved. Is it thin? Yes. Approved..
Forum member JettaRed ran non approved Pennzoil 5W-50 in a M276 with positive results.
Don't get me wrong, I am not saying to ignore the approval but there needs to be more research, I mean, there is no 229.5 approved 5W-50 oil from MB right?
yes on cold start and today i notice after 60km drive and turned off for 20-30min then it did again but quieter than the initial cold start when car sits for more than 7h https://youtube.com/shorts/Q89d_y2eo...H4A1QEhj5vQWKV
Kris, I think I've got what may be good news.
It's interesting the way this knocking sound is : Delayed before start knocking
Short duration span then quiet
The high frequency of impact
Because of that there's a chance your dealing with HPFP roller knocking on cam lobes.
GDI HPFP
pressure may still be near accurate.
Use a stethoscope to directly listen to HPFP body. $8 mechanic stethoscope (or long screw driver)
A bad rod bearing would sound different :
knock right from the beginning
fade away more slowly with oil
knock at a much lower frequency
Last edited by CaliBenzDriver; May 4, 2025 at 05:26 PM.
yes on cold start and today i notice after 60km drive and turned off for 20-30min then it did again but quieter than the initial cold start when car sits for more than 7h https://youtube.com/shorts/Q89d_y2eo...H4A1QEhj5vQWKV
I had a similar noise before when I added more engine oil that noise never returned, not sure if the same issue. This was back in 2018, never heard the noise again. Vehicle was running mobil1 0W-40.
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