Got some few experiences with those ticks like what was described.
1st had an engine flush and oil change years back, started to tick, used all kinds of blend, no dice for over 3 years until I did head gasket cleaned up head really well and no tick for a year now.
2nd truck, heard tick and saw oil was low and added oil, then disappeared until now
3rd truck, ticking once in a while. Not too bad and will check if I have time to change HG and clean up lifters.

Filter used KN#2004 or the longer version
Oil - Mobile synthetic 10-30 every oil change over 14 years
FilterMag on all vehicles

 

In used car dealer circles, that's known as "changing into your problem" which is slang for a prior owner having 30 cut oil or even 70 weight gear oil in your motor to hide the rod knock sound.

You "changed" to a proper oil grade (e.g. 15W40 is fine) and the existing rod knock became noticeable.

It's not a slipped liner. LINERS DON'T CARE about the grade of oil you use. It's not a problem with your oil filter or its size.

You can confirm the above by draining, then filling your motor with 30w30 (straight cut or true 30 weight oil).

Wow, the rod knock sound "went away!"

Magic. Except, the spun bearing is still in the lower end of your motor regressively getting worse with each revolution of your motor...you just don't really hear it because of the super-thick (not really so ok to use) 30 cut oil.


Anyway, if you were duped by a prior owner doing that trick above, no big deal because changing your rod bearings is easy with the motor still in your Disco (you just remove your oil pan to reach your rod bearings).

$38 on eBay total buys 8 new rod bearings. Replace them and then you can run a proper oil grade without hearing rod knock.

 

So if this is the problem is the only way to check to put in the 30 weight oil? Mine only knocks if I drive far enough or if it's a really hot day. I just drove up to the store less than 2 mile drive and no knock. Changed the oil last week and have had the car for 2 weeks tomorrow. No knock on our 4 hour drive home after purchase, but I did have trouble codes on the way home right after filling up about an hour from our house P0134, P0171. Cleared the codes and they haven't returned, but just got a new one a few minutes ago P0455. I checked the gas cap, seemed tight... and cleared the code. Temps according to OBDii have been around 180 consistently.

Not having the best luck so far.
I replaced 2 door actuators last week,
painted the headliner,
replaced light bulbs,
replaced the wiper blades (the front wiper fluid pump isn't working )
All seemed fine on our test drive! Changed the oil put in 15W40 Rotella non-synthetic,
changed the air filter from a K/N to Wix....
Ordered a front drive shaft just to be safe, should be here Tuesday.

It was idling rough when it was knocking. But today seemed to be driving great, no knock and them bam error code, WTF!!!

Someone on a Facebook group suggested it was a slipped liner and I should put in 5W30 oil and an oil cooler and that would fix it... Thoughts on that??

 

Are you mistaking a knock for a bad misfire? A bad misfire will accentuate a worn/collapsed piston skirt and a piston slap is definitely a knocking sound.

 

Mine sounds metallic. Very rythmic. It sounds identical to this video

 

#1: liners aren't lubricated. They are friction fit. They fit because they are *not* lubricated. Changing oil makes no impact to liners slipping (knocking) or not.

Any Disco can have slipped liners, but no Disco is going to get slipped liners based on an oil change.


#2: rod knocks do not go away with RPMs or heat. If you hear a knock that later "goes away" while driving faster or with oil hotter, then that knock is *NOT* rod knock.

Rod knock can be naturally hidden by cold oil because oil is a little thicker when cold.

Rod knock can be deliberately hidden by using a super thick oil.

The above is not saying that you do have rod knock. The above is saying how rod knock behaves IF you have it.



Your motor can make lots of noises that give you advance notice of a problem becoming more serious. Spark/fuel "knock" is different from rod knock is different from engine ticking is different from slipped liners is different from an exhaust gasket leak, etc.


If you are unsure if your noise is one of the above, then there are separate tests for each. Testing is much better than guessing by installing new parts randomly/hopefully ("hope" is seldom a great plan).


So, with the above in mind do you hear your "knock" right when you startup your cold motor?

Do you only hear your knock when your motor is warm?

Does the knock sound disappear if your RPMs are above a certain point (say greater than 2500 RPMs)?

Does your knock sound vary identically with your throttle...as in if you rev up a tiny bit does the knock increase in frequency, and if you back off of the gas does your knock ping at a slower pace?

 

Not noticeable with start up UNLESS the engine is already warm.

You don't hear it when driving down the road as the engine is louder or it dissappears, not sure which. It's only heard at stop lights with the window down, or at a complete stop, or slow enough to hear (low RPMs)

Yes the sound seems to follow the engine frequency.

 

If yours is truly that loud you need to stop driving it.

Definitely not a liner. Definitely not a piston skirt. Definitely not a misfire.
​​​​​​Sounds too high for a crank bearing and it sounds like a double tap so i'd put my money on rod bearing.

 

I would err on the side of KingKoopa above and replace the rod bearings before driving any further.

If you don't...and wind up throwing a rod through your block, then your Disco is toast.

Plus, changing the rod bearings is a cheap and easy fix that *needs* to be done in 6 figure mileage, anyway. No harm, no foul by going that route.

Sure, you could do more tests, but there is some risk with each RPM.

 

These?? Land Rover Rod Bearing Set I see a few sizes, how do I know which ones to get? It's a 2004. Are they hard to change out or would this be something to take to a shop? My husband is mechanically inclined, but gets nervous when I even hint that I want him to crack open the engine!