So i posted the other day that my 2001 Discovery II Se developed a knocking / tapping sound. I did not read that section in the manual which reads i must use nothing less than 90-92 octane gasoline or the vehicle will develop a knocking / metallic tapping sound.

My bad as i have been running 87 for the pass year. Just being cheap with the gasoline prices.

The sound is recent and after reading this section in the manual i quickly filled the tank with 92 and my question is how long will it take for the tapping sound to go away.

Or will it? Or have i done more severe damage???

I believe this to be the issue. My oil is changed frequently and the there is no discoloration in the oil. Antifreeze level is fine. I have no hesitation or loss of power at any time. She actually drives nice and i really only hear the tapping noise at a very low speed.

I am being impatient i realize. Used the wrong fuel for almost a year and now i am wanting the tapping to go away and i have only used 1/2 tank of 92.

Any comments would be greatly appreciated. Well no sarcastic comments anyway. LOL

 

Does this tapping change speed with engine (rev up while in park), or does it change with forward motion of the vehicle? If when moving, could be related to front CV swivel joints.

Some people have had tapping issues related to the secondary air injection (SAI) , you can search for that.

Some members have used a variety of oil flush products to remove sludge inside the engine, which is also not recommended by some other forum members. Basically, the addition of solvents or thinner oil (Marvel Mystery Oil) may break loose some "baked on" deposits, clearing up the noise. If the baked on crap is large enough, it can obstruct the oil pick up screen in the oil pan. The general use is something like "GUNK" brand, done at oil change. Most all solvent type cleaners are short term use and drain it out. There is a product on the market called Auto-RX, it is a slow working sovent that dissolves the sludge and holds it in suspension for the filter to grab. You have to change filter only every thousand miles, and your oil gets very dark when using it. At 3000 you replace oil with clean oil, run that for 3000, then change oil again and go back to regular service intervals.

Might work, might not. I liked my results. One thing that some users agree on is that a high detergent "disesl" oil like Shell Rotella 10W40 can do a better job of gink cleaning than regular motor oil. Some users do 1000 mile oil changes with Rotella at first, then move to 5000 mile.

It is possible for some tapping to clear up from use of an enhanced oil or oil treatment product. But you may be looking at other issues, the worst being the infamous slipped cylinder liner, which is a replace the engine item. Some users hunt for the sound by using a mechanics stethoscope (auto parts store) or a broom handle held on the motor in various spots, while the other end is pressed against your ear. Yu may be able to find the tick coming from one side or the other, coming from under the valve cover, etc.

Note: It is considered bad form to use the broom handle owned by she-who-must-be-obeyed, get your own.

Knocking from low octane gas is more noticed usually on acceleration, not steady cruise.

 

Yes you are "BAD", but that is not what is causing your knock. Where is it coming from, top or bottom of the engine? Stop driving the truck today and have someone listen to the noise, then do an oil pressure test and get back to us with the 4 readings.
You will then need to have someone open up the engine and find the potential failure.

 

I hear nothing when i am driving it. I just backed it up and heard nothing. Its only when i take off from the stop position. And i guess the knock increases on acceleration but then as i said disappears. I do not hear it at all with the windows up. During the winter months when i drive it out of a snow bank the traction control would make this tapping sound or like placing a credit card and hearing it slap again the spokes of a bicycle. At first i thought it was a low sound from perhaps the traction control. You can tell i am clueless as to how to explain. lol

 

Ok, open your hood and start the engine, then rev it by hand, that means using the throttle cable open the throttle adn increase the engine RPM, do you hear the noise?

If not then it is not the engine it is something in the driveline.
In which case you need to get it inspected ASAP.
Any shop can inspect your driveline for you.

 

OK. So if I get this right,

No knock or tap when driving at 25 - 30 mph, on level ground.

Knocks on acceleration, but knock goes away or is covered up by vehicle noise.

Don't hear with windows up.

What about at idle, cold or warmed up, if you give it some gas (rev up motor to say 1500 rpm)?

Does knock appear to follow vehicle speed or engine speed? Any change when turning?

If you are getting the knock, and let off the gas, does it stop right then?

First, let me say that it is a good sign that the noise is not present at idle.

Second, it would be prudent to follow Mike's advice.

 

Is it possible i have a faulty knock sensor from using the 87 octane gasoline instead of 90-92 for almost a year???

 

Knock sensors "sense", they don't make noise. You have metal hitting metal, the question is where (engine vs drive train) and why. You have gotten plenty of good advice, but if you continue to operate the vehicle the noise will become much more expensive. And then the only noise you will hear is the jingle of change in your pocket, because the wallet will be empty!

 

Are you sure it is not your front drive shaft, has it ever been rebuilt? Crawl under and make sure each of the 4 u-joints has a grease fitting.
Do you have a check engine light, have you checked for faults if so, what are they?
As I mentioned before, do not drive it any more till you can have a qualified Rover mechanic, not the dealer, check and estimate the damage.

 

I have not ever had the front drive shaft rebuilt. I will crawl under and look. The engine light has never come on. Fluid levels are normal. Temperature is normal. I will promptly make an appointment to take it to a rover mechanic.

Another thought....

Over the past months my "3 amigoes" lights come on. I pull over, turn off the rover and re-start and lights are out.
This past winter whenever i would try to drive the rover out of a smallest of plowed snow or even when the traction might night be perfect the rover would make a noise ( poker card against bicycles spokes sound ) and then when on normal surface would end.

Its almost like that sound but now constant and of course i do not hear it when it is idling.
Could it be a traction issue?

I get confused by using words such as Knocking, Tapping and Ping sounds.

In my manual it states "....using less than 90-92 Octane the engine will develop a heavy knocking / metallic tapping sound...". I have been using 87 for a year. How do we know the knocking/tapping/pinging sound i am hearing is NOT a result of a fuel issue?

So lets say it is indeed an issue as you have mentioned. Then please explain to me exactly what the sound will be as a result of me not using the correct fuel and then why would Landrover have that paragraph in the manual as a warning?

I realize i need to take it to the dealer, but if it is just the fuel issue it would be great to try to resolve it on my own and also i would like a better understanding of the difference between Knocking, Tapping and Pinging.

I am not at all mechanically inclined and perhaps i am using the wrong terms to explain my issue.

But the end result is i do not want to cause more damage to the vehicle as its in mint condition exterior, inside and would like to keep under the hood mint as well.

Thanks everyone.