I have 2012 c300 4matic luxury would this work are the lifters in it hydraulic? Thanks

Your C300 does have hydraulic lifters.

I have a 1999 Mercedes cl 500 with an m119 engine. Will this help? Can I also use ceratec at the same time. How much of each should I use? and do I have to remove any oil before putting the additives in so it doesn’t over fill?

Yes, it can be used and may help. One bottle will treat up to 6 liters of oil. I would check the oil level first before adding in to see if it's necessary to drain some oil.

Can this be used on a 2011 f10 N55? How much do I need to add?

Yes, it can be used. One bottle will treat up to 6 liters of oil.

Have you ever heard of an N52 engine (2010, 200+k) with operable yet chattering lifter(s) to the point where it reduces airflow into a cylinder, causing a rich mixture, then leading to lean mixture in remaining bank cylinders, leading to pinging/detonation under light to moderate acceleration? All without any engine codes? I've got 3 symptoms, not sure if related: --chattering, particularly after cold start AND then driving under light to moderate load. --#1 spark plug blacker than others. --LIGHT detonation under light to moderate acceleration. Could these all be related? Something common? What are the possibilities? Thank you

It's not something that I've heard of and sounds like the issues are related. It's tough to say what would be causing that without looking at the vehicle and engine diagnostic.

If adding 300ml of this plus 300ml of Cera Tec at oil change should approximately 1/2 a quart of oil not be added? This is on a 2014 Z4 N54 so no dipstick for reference when filling.

No, you add the same amount of oil to the engine regardless of the amount of additive. These additives are carried in mineral oil which burns off and the additive mixes with the existing oil. The amount of total additive being used has no effect on the oil level.

can this addictive be used in an m20 engine on a 91 325?

There is no point in using this additive on an M20 engine. The M20 engine is a solid lifter design with no hydraulic compensating element. So using this additive on that engine won't provide any benefits. If you are concerned with "lifter noise" it's actually very common on the M20 because of the solid valvetrain. Would check to make sure the valve lash is adjusted properly and possibly go to a higher viscosity oil which will help cut down on lifter noise. However, there will always be valvetrain noise because of the rocker/valvetrain design.

Is this product a full synthetic additive?

The carrier oil for the additive is mineral oil which burns off and the additive then dissolves/blends into the existing oil fill of whichever oil you are using.

I have 2013 S63 with a tapping noise on the left front head. Will this Hydraulic Lifter Additive help me or is it not your recommendation?

You will need to verify the component that is the source of the noise in order to determine if this product will be effective.

Can this product be used and added alongside with Liqui Moly's CERA TEC Engine Oil Additive? Or would that be overkill and only one or the other product should be utilized?

The two products have different properties. It is not overkill to use both, but I would not use them on the same fill.

I have a lifter tick in my e90 N51 engine with 120k miles. Was going to add some CERA TEC to quiet down the lifter but then I came across this stuff. Which one would be better to use for lifters, cera tech or this or both?

This should help reduce lifter noise in your N51 engine.