xxaarraa

****This is not intended to be an oil thread. I am merely sharing my idea, not encouraging anyone to do anything differently. Not intending to stir the "which oil is best" pot. Please don't turn it into one of those threads *****

Background: 2014 Z51 here, A6. Have a very audible ticking/exhaust leak type noise from the driver's side of the car. I have extra sound deadening so this noise is even more prominent and driving me nuts. Coming from an AMG with an M156 (one of the best sounding motors of all time), I find this annoying ticking/exhaust leak/sound of running water to be completely unacceptable in a sports car. Anyway..

I took the car to a Chevy dealer and their supposed corvette tech flat out pretended my noise didn't exist. He used their standard "I don't hear anything abnormal" bs line. Car is now at a different dealer who acknowledged the noise, but said "I am not sure yet what I will be able to do about it, if anything. I will call Chevy first"

I did a search on the forums and find that "lifter noise" is common for these engines? Which makes me believe that chances are high that even the second dealer isn't going to do anything about it.

Anyway, long story short, this brought back memories of when I had my 911. Those flat-6s had valve tappet noise while running low-zinc oil (aka mobil 1 0-40) and it was common in the 911 enthusiast community to switch to a high-ZDPP oil. I used Driven DT-40 and it cured all the clattering/tappet noise.

So, if Chevy dealer is unable to fix this issue, I plan to switch to DT-40 or another high-ZDPP oil on the vette and see if that helps the situation. Oil manufacturers started going to a lower zinc blend because zinc is harmful to catalytic converters, and they were being forced to warranty catalytic converters for 8 years. That's one theory anyway. More and more, as each day passes, I am increasingly unimpressed by Mobil 1. My previous AMG was switched out of Mobil 1 0-40 because the M156 sheered right through it and would consume more oil than with other brands.

Anyway, just sharing. Not looking to convince anyone or take sides.

juanvaldez

I don't see any real downside. I switched to Mobil 1 0w40 last oil change and haven't notice any differences.

NSC5

The zinc problem is real IF you are running a stock exhaust system with intact cats. However I think the noise you are hearing is from the high pressure common rail fuel system, primarily the camshaft driven high pressure pump, and higher zinc content oil will do nothing to quiet it.

ersatz928

Zinc is a high pressure lubricant, to protect surfaces. If something is already worn, changing to a high zinc oil won't quiet it down.

Toombs

I have the really annoying tick as well. It's the only thing I dislike about the car. I'm embarrassed to pull up to a stoplight, it's that loud. Passengers always ask "whats that noise?" I haven't had it looked at yet, afraid that they will say it's just the direct injection. But it seems far too loud. I wish you luck, keep us posted.

BlueDevilZ51

Bill Dearborn

First, if the noise is due to a lack of lubricity in the oil it is already too late. I seriously doubt the noise is related to the valve tappet noise you heard on old engines. The LT engines use hydraulic roller lifters and don't have the same wear characteristics of a tappet lifter. The lifters don't need to be adjusted and if one is tapping it usually means it has to be replaced. I suspect the tapping is related to the fuel system. If the tapping goes away as the oil temperature gets into the 110 degree range then it could be a piston slap issue that goes away with the piston increasing in diameter to fill the cylinder. The LS engines had a fair amount of piston slap. At track events you could hear a lot of tapping coming from C5s as the owners warmed them up before heading out for a mid 30s to mid 40s ambient temp track session.

I recorded the typical sound they made as a buddies engine was warming in the garage at the Glen a few years ago:


There were at least 10 C5s sitting in the garage tapping like this. Nobody thought anything about it as it was truly normal.

Bill

davepl

I'd agree with Bill, the only noises I've heard are the high pressure injection (kinda sounds like a diesel) and some piston slap, but I don't get the latter on my LT4. My Range Rover is much noisier.

The risk you run with ZDDP oil is in clogging up your catalytic converters. I presume that's why they have slowly removed the ZDDP from the oil in the first place.

xxaarraa

Well, I heard from the dealer. The tech acknowledged the ticking noise, called Chevy. Chevy told him it was normal and asked him to start up two of their brand new cars. Tech says brand new cars make the same noise, so he can't help me. Fully expected this, and it's a bummer.

The ticking is a major derailer for me, and takes away a huge part of my driving experience. If I end up selling this car sooner than I otherwise would, this would be the # 1 reason. I don't care what the reason is, but a $74k sports car shouldn't sound like a food blender. I had very low tolerance for the 911 doing the same thing too and I'd judge any high end performance car the same way - with high standards.

In other news, they did give me brand new rotors (and pads) as part of the TSB since my original rotors had started to pulse upon braking starting at only 7k miles. I believe the TSB said to replace the old two piece rotors with one piece rotors. Which is a bummer because I imagine the 2 piece rotors were put in there to start with for good reason (better cooling, longer life, lower weight) but now they are gone.

http://www.corvetteactioncenter.com/...pply-1270.html

Toombs

I've seen the one-piece, they do look better designed , so I think you're better off there. Bummer on the ticking. It's driving me crazy as well.