Has anyone used liqui moly hydraulic lifter oil additive?

[S6Man4.0tt]

From google:

"With “overhead cam” (OHC) engines, the camshafts are in the cylinder head(s) and actuate the valves directly or via cam followers, so there are no lifters. However, most modern OHC engines do have some type of hydraulic valve lash adjusters."

"A "cam phaser" is just an adjustable camshaft sprocket that can be turned by means of a computer-controled servo. ... Additionally, dual-overhead-cam engines, with one cam for the intake valves and another for the exhaust, can use these cam phasers to change their position relative to each other."

Does the 4.0 have hydraulic lifters or hydraulic valve lash adjusters? The engine guide did little to enlighten me. I'm noticing a pretty bad knocking sound on the passenger side front of the engine with only 14k miles. I just replaced two heavily leaking fuel pumps that where probably leaking onto these areas for years (car is 7 years old). There where a lot of lifter sounds that went away on starts after replacing and changing the oil after but the knocking sound is still there on that side only.

I'm curious if liqui moly hydraulic lifter oil additive could help a bit. I know it does a good job in the case of hydraulic cam followers and it sounds safe. I know I need to get all of the fuel and carbon out of the engine in tight places and anything might help or generally make the valvetrain run better. It is supposed to get inside of those parts and clean it out. I could imagine fuel being trapped inside of the lifters/adjusters if they have a hydraulic component. I'm guessing it won't get rid of the knock but maybe some people have experience with it.

[gk1]

I know Audi goes out of their way to specifically state not to use any oil additives.
In your case though it sounds like damage has been done. An oil additive might act as a band aid as damage continues. You most likely need to have a qualified mechanic look into the true cause of your problem.
Knocking is a universally bad sign and generally tapping (consistent with hydraulic lifter noises) is a different sound from knocking. (Video might help.)
Did the HPFP fail from wear on the cam follower? If so, then it is possible poor maintenance (as well as the fuel dilution) may translate to the rest of the entire engine and there could be issues anywhere.
Also are you saying the car is 7 years old with 14k miles and already needed HPFP replacement and is knocking? Was your recent oil change it's first one or have you been doing them yearly?

[core5]

Liquimoly and some others makes engine flush, which is just an aggressive detergent mix. You put in the specified amount for your oil volume and run the engine for a certain amount of time (30 minutes at low load is typical). Then dump it out.

The 4.0t has rocker arms and rollers under the camshafts, so you won’t get the cam and lifter wear like on flat tappet designs. The only valve train failure I’ve heard of is the sodium filled exhaust valves on the RS cars failing occasionally.

You may want to have a shop take off the valve cover and see what’s going on on that side.

[S6Man4.0tt]

The oil was changed every year, most years with around or less than 1k on the oil. I have the complete record. So that is good. It was one owner. Car is like new. The oil has been changed 3 times in the last 1500 miles and 4 months. Yes somehow the HPFP where completely shot at 13,400 miles and 7 years. No I don't think it's engine knocking but something else that sounds like knocking. You have to be very close to hear it. Sounds like a hollow knocking sound. Very distinct in one spot. I think it's valve related from the gas draining on that area it is right below the HPFP passenger side. I will ask my mechanic soon. Engine sounds really good otherwise and is much more quiet since changing the pumps and oil. I'm feeling pretty good about it in a way now so quiet and smooth after about 200 miles on the new oil I was used to it sounding bad especially on starts. I am pretty paranoid though and starting the car with the hood up and stuff listening lol You can't hear anything inside the car of course.

The liqui moly flush is not liqui moly hydraulic lifter additive. I do use engine flush and it's good and I recommend it. The hydraulic lifter additive is something you leave in your oil after changing the oil. It specifically cleans out hydraulic lifters and quiets down ect it is supposed to be safe and harmless. Lots of people have used it in BMW and Mercedes cars and seen a huge difference in rough valvetrain sounds watch some vids its pretty impressive. It is made for german stuff. I wouldn't recommend it for these cars though either unless your sure.

[Optimus247]

Wait ... In no way am I trying to be mean or otherwise ... Just sorting the Facts ... (honest)

" I do use engine flush and it's good and I recommend it. " ... Are you using synthetic Oil ...? Because synthetic oil is already a hydraulic cleaner with lubricity ... with such low mileage, a flush should not needed ...

A flush is usually required on higher mileage, additive deficit oil usage ... Your recommendation is not sound based on your predicament ...

If an oil change made a huge sound change ... maybe the weight is improper ... Remember ... additives in syn oil make it thicker, as additives burn off the syn oil gets thinner ... and the reverse for Dino oil ... additives in Dino oil make it thinner, and as additives burn off ... Dino oil becomes thicker ...

Best of luck on the knocking sound ... I wish for you a good mechanic to verify a simple and cheap repair ...

Again ... I am trying to help and NOT bash .. Peace be with you ...

[S6Man4.0tt]

Wait ... In no way am I trying to be mean or otherwise ... Just sorting the Facts ... (honest)

" I do use engine flush and it's good and I recommend it. " ... Are you using synthetic Oil ...? Because synthetic oil is already a hydraulic cleaner with lubricity ... with such low mileage, a flush should not needed ...

A flush is usually required on higher mileage, additive deficit oil usage ... Your recommendation is not sound based on your predicament ...

If an oil change made a huge sound change ... maybe the weight is improper ... Remember ... additives in syn oil make it thicker, as additives burn off the syn oil gets thinner ... and the reverse for Dino oil ... additives in Dino oil make it thinner, and as additives burn off ... Dino oil becomes thicker ...

Best of luck on the knocking sound ... I wish for you a good mechanic to verify a simple and cheap repair ...

Again ... I am trying to help and NOT bash .. Peace be with you ...

No prob. Yea just changed out motul excess gen 2 5w40 for liqui moly temporarily. About about to do another change after about 500 miles to torco sr5 5w40. Going to try to get the remaining bit of fuel out of the oil and to see what the oil looks like now.

Engine flush is good to start using early on actually before carbon builds up and keep it that way IMO. Its a bit dangerous to use at high mileage if it hasn't been done before IMO. It can knock too much carbon loose and actually backfire and settle and clog stuff up at that point. The idea is just to keep the oil lines and screen clear. This is not liqui moly hydraulic lifter additive which you put in AFTER you change the oil. It's not a solvent it's an oil additive. They are two completely different things. One function is it does clean as well.

The oil change made a huge difference on cold starts with sounds yes. I had oil dilution from leaking pumps, I removed the diluted (with gasoline) oil. That's why it made a difference. On the good side the knocking sound isn't very loud can only hear it from up close. I hope I'm just paranoid. My mechanic will take a look when I put on APR downpipes in the next week.

[gk1]

The oil change made a huge difference on cold starts with sounds yes. I had oil dilution from leaking pumps, I removed the diluted (with gasoline) oil. That's why it made a difference. On the good side the knocking sound isn't very loud can only hear it from up close. I hope I'm just paranoid. My mechanic will take a look when I put on APR downpipes in the next week.

If the noise is not that loud it may just be "normal" engine sounds. The motor makes a lot of noises from the injectors to the Secondary air to just the valvetrain in general. If you can find someone near you with a 4.0T in good working order maybe try to compare.