6L V8 noise on cold start - Bottom end bearings v Lifters v Piston slap v Oil pump

[vombil]

Did you know that you can drive into SuperCheap and ask a tech to either check the oil pressure or show you how to check it using OBD it for ~$20 plus the ELM?
Without either a video of the event capturing the noise in some shape or form or any hard data in black and white, is not just anyone’s guess what it is, it’s logically a waste of time.
First step is to pinpoint where the noise is coming from and why, to do that you need to gather something to work with as above - video and or oil pressure reading.
I mean could be any moving part and not even part of the engine!

So i did the accel to the floor and cranked maybe 4-5 revolutions, two times. There was no knocking and no lifter noise when it fired - just a pretty mild piston slap that cleared completely after about 30 seconds and did not get louder or return with light increase and stabs of throttle. I'm not sure this a great test to isolate the lifters as the cause (which ive read elsewhere as well) of the noise as it would also lube the cam and crank so masks bearing/oil pressure and or oil pick up issues as it's priming the whole engine.

 

[vombil]

ill borrow the scanner tomorrow and report back - albeit only a restart a day later which hasn't given any problems yet. I'm going to do an oil service and chuck some lifter free in there too

 

[georgieboy]

Did you know that you can drive into SuperCheap and ask a tech to either check the oil pressure or show you how to check it using OBD it for ~$20 plus the ELM?
Without either a video of the event capturing the noise in some shape or form or any hard data in black and white, is not just anyone’s guess what it is, it’s logically a waste of time.
First step is to pinpoint where the noise is coming from and why, to do that you need to gather something to work with as above - video and or oil pressure reading.
I mean could be any moving part and not even part of the engine!

hello , i think it must be your oil .
i am running mobil 1 5-30w in an engine with 30k klms and on a cold day around 4 deg c it makes a slight noise on start up then
it goes away.


thanks
george

 

[vombil]

hello , i think it must be your oil .
i am running mobil 1 5-30w in an engine with 30k klms and on a cold day around 4 deg c it makes a slight noise on start up then
it goes away.


thanks
george

this makes noise at 10-14 degrees after sitting for days on end. no issues overnight - 48 hours

 

[vombil]

did an oil change with Nulon 5/30 dexos approved blah blah oil and dumped a bottle of lifter free. I waited probably 8 days or so (sat idle) with the view to put the scanner on it and get oil pressure. the owner of the scanner convinced me i'd be wasting my time with a scan - i'd need to check it manually as his scanner is only going to tell me what the cars system would, if there was a problem.

so anyways I started the car and there was no concerning noise.... definitely no knocks

 

[moveage]

@vombil thats good news about symptomatic relief.
You still need to log oil pressure to diagnose the mechanical issue. Scanner owner was referring to the logic that if the car doesn’t display Check Engine then likely there’s not going to be a DTC a code showing. Two different things, never heard of plumbing an old mechanical line before checking modern sensor readings.

 

[rucxy]

Sometimes modern sensors do fail or send incorrect data through.

 

[moveage]

Sometimes modern sensors do fail or send incorrect data through.

Sure. Logically that’s not the case here though. Audible noise, sensors warn of nothing outside normal parameters. So the issue right now is what do they report.

 

[vombil]

Sure. Logically that’s not the case here though. Audible noise, sensors warn of nothing outside normal parameters. So the issue right now is what do they report.

so we were discussing an analogy to use to describe what might be happening. we came up with drying clothes inside your house. after one day they are mostly dry, day two - probably dry and day three or four - crispy dry. So he's suggested that by day 6 or whatever it was that there was absolutely no oil left anywhere in the motor other than the sump- it just keeps draining or 'drying' like the clothes. bearing clearances too great and allowing oil to drain off in it's entirety was thrown around too. He suggested 10/40 and move on to more important things in life

 

[vombil]

@vombil thats good news about symptomatic relief.
You still need to log oil pressure to diagnose the mechanical issue. Scanner owner was referring to the logic that if the car doesn’t display Check Engine then likely there’s not going to be a DTC a code showing. Two different things, never heard of plumbing an old mechanical line before checking modern sensor readings.

i took the turtle shell off dude and couldn't see a thing behind the intake. god knows how I get the pressure sender off and a mech line on there. maybe lay on top of the motor? I replaced a oil pressure sender on VY LS1 and dont remember any issues