Rumble Butt
Thread Starter
Intermediate
Joined: Jun 2025
Posts: 47
Likes: 11
Rumble Butt
My Vette when sitting in idle, you basically get a butt vibration massage. The performance shop who did my exhaust said the valves need cleaning since I'm at 29K on 2014 Z51. Is there a Autozone solution we can buy to clean our valves or is it somethign dealerships can handle?
Team Owner
Joined: Sep 2000
Posts: 24,992
Likes: 2,694
From: Far NW 'burbs of Chicago
St. Jude Donor '13
Our 2017 Z51 is at 65k miles, plugs & wires replaced at about 55k for another problem but it vibrates about like any other C7 and always has.
If you need the valves cleaned at 29k, something is really wrong.
Other mods on the car?
Even if you use cheap gas instead of Top Tier, I wouldn't expect the problem to appears at those low miles.
If you need the valves cleaned at 29k, something is really wrong.
Other mods on the car?
Even if you use cheap gas instead of Top Tier, I wouldn't expect the problem to appears at those low miles.
Thread Starter
Intermediate
Joined: Jun 2025
Posts: 47
Likes: 11
I've only owned it since 28K June 2025, only premium gass since. The performance shop who make their living tearing LTs down and building up said it is very common for LTs at this mileage. Said back of the valves is where the problem is and get gunked up. I have no reason to question a performance shop who tears LT apart and rebuild all the time.
Team Owner
Joined: Sep 2000
Posts: 24,992
Likes: 2,694
From: Far NW 'burbs of Chicago
St. Jude Donor '13
Premium gas is not necessarily Top Tier. You can Google "top tier gas" for a list of the companies that meet the standard.
On DI engines like we have, that's not as helpful as it used to be, but still recommended in our Owner Manual. Some people claim the Top Tier standards were developed by the oil companies as an excuse to raise prices a little, but the standards were actually established by the car companies as a way to reduced warranty claims and expenses.
If your engine is opened up to clean the valves, they will probably show some deposits. But not enough to effect performance in any meaningful way.
A driveshaft/torquetube problem can also cause vibration, but your situation seems different.
You could try posting about your problem with a title like "Dirty Valves Causing Vibration?" in C7 General, that should get more replies from people smarter than me.
On DI engines like we have, that's not as helpful as it used to be, but still recommended in our Owner Manual. Some people claim the Top Tier standards were developed by the oil companies as an excuse to raise prices a little, but the standards were actually established by the car companies as a way to reduced warranty claims and expenses.
If your engine is opened up to clean the valves, they will probably show some deposits. But not enough to effect performance in any meaningful way.
A driveshaft/torquetube problem can also cause vibration, but your situation seems different.
You could try posting about your problem with a title like "Dirty Valves Causing Vibration?" in C7 General, that should get more replies from people smarter than me.
Safety Car
Joined: Dec 2012
Posts: 3,835
Likes: 1,853
From: St. Louis Metro East IL
C7s all have direct injection engines. No gas or gas additives contact the back side of the intake valves. According to the retired Corvette Chief Engineer, valve deposits should not be an issue. Of course, you may be the "lucky" one with issues:
https://www.corvetteforum.com/forums...on-valves.html
Ron
https://www.corvetteforum.com/forums...on-valves.html
Ron
Team Owner
Joined: Sep 2000
Posts: 24,992
Likes: 2,694
From: Far NW 'burbs of Chicago
St. Jude Donor '13
^^^^^
That is correct.
But GM still recommends Top Tier for reduced deposits in other areas, like piston tops and the rest of the combustion chamber.
Regardless, I doubt that his vibration is caused by dirty intake valves.
That is correct.
But GM still recommends Top Tier for reduced deposits in other areas, like piston tops and the rest of the combustion chamber.
Regardless, I doubt that his vibration is caused by dirty intake valves.
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Le Mans Master
Joined: Oct 2008
Posts: 5,703
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From: Irving, TX
Unless the PCV has been dumping oil back into your intake the valves should be fine. I'd be skeptical of your shop. That said yes it's actually quite easy to pull the intakes on these cars and clean the valves yourself with a bit of time, solvent and a shop vac. You can look up LegitStreetCars on youtube and search for his valve cleaning video. He cleaned the valves on his wife's LT1 Escalade. It's even easier on vettes because once the intake is off the intake ports are right there and you don't have to climb on top of the engine. If you do pull it just get yourself some new intake manifold gaskets, they are very easy to change. Once you pull the intake the first time you can remove and install it in 20 minutes.
Burning Brakes
Joined: Jun 2021
Posts: 801
Likes: 408
From: NC
I've only owned it since 28K June 2025, only premium gass since. The performance shop who make their living tearing LTs down and building up said it is very common for LTs at this mileage. Said back of the valves is where the problem is and get gunked up. I have no reason to question a performance shop who tears LT apart and rebuild all the time.