Will marvel mystery oil help quiet your lifters

Lifter noise is typical of an oil pressure issue, or when oil channels are clogged from infrequent oil changes.
You can start by changing the oil and REPLACING THE FILTER. Marvel Mystery Oil or other oil treatments will help clean the oil system and quiet the lifters. If an oil change and crankcase oil additive helps quiet the noise, change your oil every 500 miles for at least 2000 miles, and the lifter noise is likely to stop.
Are you getting a CHECK ENGINE light, or an OIL PRESSURE warning? Have ODB codes checked, and be prepared to replace the oil pump or oil pickup tube, especially if the car has over 150,000 miles. Once you have correct the issue, change oil more frequently.

See if you can find Marvel Mystery Oil at an auto parts store and add it to the oil . Let it stay in for a couple hundred miles then change the oil

something is restricting the flow to the valve lifters. I like Marvel Mystery Oil brand
to clean oil passage and quiet noisy lifters. may take a week of driving to notice the difference. If that doesnt help I would find another dealer that will take a little better look at the problem

YOU HEAR VALVE LIFTERS.MOST TIME YOU HEAR VALVE LIFTER NOISE.LIFTERS ARE WORN OUT OR OIL + FILTER COULD NEED CHANGING.BECAUSE DIRTY OIL WILL STOP UP LIFTERS CAUSE THEM BE NOISEY.YOU CAN ADD BOTTLE OF MARVEL MYSTERY OIL IT WILL HELP QUIET DOWN NOISEY LIFTERS.

you might have a varnish coating on the lifter. Add some Rislone or Marvel Mystery oil and see if dissolves the varnish

YEP BUT NOT REALLY.DO THIS LITTLE TEST.CHANGE OIL + OIL FILTER.BUY A BOTTLE OF MARVEL MYSTERY OIL FOR NOISEY VALVE LIFTERS.IF THIS DONT STOP THE LIFTER NOISE.LIFTERS ARE WORN.ALSO MAKE SURE YOU ARE USING 5W - 30 OR 10W - 30 MOTOR OIL.

Not sure what you mean from a faint knocking. Faint Knocking noise refers to piston slap till the engine warms up and a Tapping noise refers to a noisy lifter, if it's a bad lifter. The noise would get louder as the engine's RPM rises. Most GM owners have the problem of Piston slap first thing in the morning when the engine is cold, it's common and was made that way. The tolerance clearance between the pistons and cylinder walls are quite large since the majority of people do not warm up there car, so as you get on the gas and the pistons expand to the right size and will not wear out the cylinder walls giving the engine a longer life. The side effect to this is piston slap till the piston expands, that's why they say that you just have to warm up the engine for 2 min and then drive. Personal I'm not one to get in and drive, I'll always warm up the engine enough to see the temperature gauge go up. My wife has a Montana with over 150.000 miles and no piston slap after the first oil changed. I found that adding some Lucas engine oil treatment and a can of Engine Restor every second oil change has kept the engine running smooth and quiet, And about 500 miles before the next oil change. I add a bottle of Marvel Mystery Oil, the Mystery oil is thinner and will clean out the internal oil journals to the crank shaft and lifters which would cause the noisy lifter if the oil passage ways are sludge up. The Mystery oil will also clean the Oil Pump Pick Up Screen, ensuring there is not oil restriction in your engine. I have a GMC jimmy with over 350.000 miles and engine still running 100% with this method of service. Good luck and if your due for an oil change soon, add the Marvel Oil and a few days later change the oil and filter and add a can of Engine Restor and some Lucas oil treatment. This should quiet down your engine and add a few more years to it's life. Keep me posted, be glad to answer any more questions you may have.

put a pint of marvel mystery oil in with the engine oil. that will help free up the sticking lifters. good stuff

We can try the easy way and hopefully it can fix the problem.
You can try adding some Marvel Mystery Oil to the Engine oil every oil change for the next few Oil change. The Oil is thinner and will clean up the inside of the engine, if there is dirt in the Oil journals that is restricting oil to the Lifters. The Mystery Oil will free it up and use 5W30 on the V W, the engine don't work well with thicker or dirty oil.
The Mystery Oil will also clean up the OIL pump screen if it's also gunked up with oil sludge and carbon deposit, so make sure you keep an eye on the oil and change is every 3000 Miles if not sooner. Depend's on how dirty the engine is on the inside, soon as the engine is cleaned and lifter's are quiet. Just use 5W30 and be faithful on the Oil change and you will start to hear singing and rainbows appearing. LOL
Good luck, if this does not work then it's going to be a valve job.

You can try adding Marvel Mystery oil about 1000 KM before your next oil change and hope that would clean the dirt from the lifter's. If not, your cam's could be worn. Good luck and try not to run in the high RPM's with the thiner oil in your blazer.