Hello, I need help with identifying and possibly fixing some engine noises. It is a 2001 C5 with 260k kilometres. I will attach video of my engine sounds. In person its a bit different, I would describe it as a mix of sewing machine+motorbike chain+ball bearings stirred in a plastic cup. I noticed those weird sounds atleast a year ago, I dont feel they are changing over time nor with engine temperature much, but I feel like they got more audible after recent fresh oil change. I use 10-60 millers oil, aprox. 8 liters per change every 8-9k kilometres + toped with random but good enough oils, arround 0,5l between oil changes, as I collect quite some of it in catch can. Intake, engine and exhaust system are stock. Those weird sounds are most audible between 1100-1400 rpms if I just feather the gas or let it go completly from bit higher ones in 1st, 2nd or neutral gear. I dont hear or notice anything in high rpms and other than that car behaves and feels nice.engine wise.

 

I don't know anything about Miller's 10-60 oil. That's mighty thick oil if it's 60 weight oil, and could be part of the problem. A lot of guys on these forums choose to run different oil than GM specs on the oil cap. Many of those same guys would be a lot better off running the 5w-30 Mobil 1 oil spec'd on the cap......

 

My C5 makes an identical (like, you could have recorded my car there) clatter. It did it on 5W-30 Castrol, and it does it on 0W-40 Mobil as well (with Liqui Moly MoS2 treatment). Coincidentally, mine also got a little louder after a recent oil change; the engine otherwise seems happy, runs strong, and the noise does come and go.

Seems a bit better when it's warm, but it's done it since I've had the car (six months), and I suspect it's done it for a long time. My assumption is that it's related to the lifters, and I've heard others speak of similar (but not heard clips to match up that description), but it could well be something else.

I've yet to really exercise my Corvette (it's a longer-term project), but once I've got it back on the road I'm going to give it a good thrash and if the noise persists, I'm tempted to try some Wynns valvetrain cleaner, get it hot, put some miles on it, and then change to a different oil again, maybe a 5W-40. I don't think the grade of oil is really a factor, though, but I'm just nosing around until I find something that the engine seems happiest on.

I'd raise a slight eyebrow at putting a 10W-60 in, though. I mean, that's 100 per cent more viscous when hot than the OEM spec. That's a lot of extra work for the oil pump, and bound to introduce a few other losses, too.

 

it s just the normal sewing machine noise they make..
i would say 10/60 is your biggest problem

 

Change the to 5w-30.

There’s going to be some valve train noise anyway, but it will be less.