Newb here. Just got a 2000 Disco 2, V8, 228k mi. Bought it at auction, history completely unknown. So, uh, yeah.

Anyway it runs, shifts, handles great - no complaints. In preparation for oil change I did a flush: one can of Seafoam and 1 qt of ATF. Used this on my other car and it helped a lot.

After 100-ish more miles of driving I changed oil & filter. Oil that came out was dark, but not horrible. It was also noticeably thick. The oil I put in was Rotella T6 5W40.

Now engine feels more powerful (noticeably less sluggish) but occasionally there is a tapping sound while under load. It's not loud, just audible. Only comes on sometimes, while engine is warm. I drive the beast pretty gently, but if I'm pulling a hill and the tapping starts, I can definitely modulate it (on/off) by letting up a tiny bit on the gas.


I've searched some and seen a few causes of tapping (oil pump, loose sleeve, lifters, bearings) but didn't come across any cases similar to mine. So a few questions:

1) Is a light tapping serious, as in "don't drive it!" ?

2) If I run a thicker oil to make the tapping go away, is that harming the engine (other than power & efficiency) ?

3) Does the fact that the tapping appears while under load hint at a likely cause?

I got this truck cheap ($950) as a second vehicle, hoping to get another 20-30 k miles out of it over a decade. But TBH I am enjoying it much much more than I expected. So if there's something that can be addressed without going down a rabbit hole, I'd like to really like to know my options.

 

My first thought was pinging, which usually happens when warm and under load (two things you noted). Are you running 91 octane (I noted you're in CO)?

 

Yes, I should have mentioned that. I only use premium, which here in Colorado is 91 octane. Bought at my normal station. I used a bottle of Techron FI cleaner, but that should be consumed by now.

Just tonight, after starting this thread, I went out for a drive. From a cold start to full warm up and returning home (up a hill) I listened carefully and didn't get any ticking at all. So it's not a regular thing.

The other thing I found when googling (not LR specific) was that an exhaust leak can cause a ticking sound under load. So maybe I should check my exhaust bolts?

Also, I ordered an oil pressure sender. Eventually plan to hook it up to an Arduino or similar, but in the meanwhile I can check it with a voltmeter.

 

5W40 is too light.

15W40 for the win!




Anyway, regardless of the oil wieght, it is important to know if the tapping/ticking starts when increasing RPMs or if it starts when you decrese RPMs down to idle.

Different problem depending on answer.

 

I agree...a little heavier on the oil.

 

I'll respectfully disagree with the oil viscosity comments thus far but there's no need to turn this into an oil debate (plenty of those threads already exist). If a vehicle in Colorado is parked outside during the winter, 5W-xx is a better choice than 15W-xx. Single digit temperatures and my oil light have demonstrated this. The oil viscosity chart in the Rave (that I have) also documents the need to stop using 15W-xx, and go to a 10W or 5W, when outside temps drop below freezing. Oil viscosity charts (not LR specific) are all over the place for 15W-40; some say 32F/0C is the bottom end, and some say single digit F/below zero C is the bottom end of the temp range for use. What I know is that my oil light won't stay on for an uncomfortable amount of time in the winter with 5W, but it did with 15W.



True. I never seem to have a problem with the manifold-to-head bolts... it's always a leak at the manifold-to-pipe connection, and I usually find either a loose nut on the stud, or a missing nut. Just tightened up a couple of nuts last week because I had a ticking sound which was new (and familiar). I bought new nuts this year, but they just don't seem to hold very well. For now, I just snug 'em up when I hear the tick.

 

What are the answers?

The one time that's clearest in my memory is approaching and climbing a hill at say 30 MPH. As the grade/load increased the ticking started. I let up on the gas almost imperceptibly and the ticking stopped. Tiny bit more gas, ticking restarted, etc.

Before the oil change, I didn't notice any ticking. After the change, it only happens occasionally.

As for viscosity, I think I'll stick w/ the 5W40 through winter, then maybe try the 15W40 . I don't know what was in there before, but just pouring it from pan to jug (while warm!) it was noticeably thicker than I'm used to. And yet the oil light wasn't complaining.

In terms of the ticking sound, it sounds exactly like my old Isuzu Trooper which had a classic issue with lifters ticking (while cold). Used to be you pick up a Trooper/Rodeo for cheap b/c of "rod knock".

 

Low octane gas has those same characteristics. Use 93 for a couple weeks and see if it goes away.

Is it a single tick or more like a multiple sewing machine tick?

 

Hi Shane,

I live/drive at 6000 ft (and up!). Around here 91 octane is as high as we get. The reasoning is that detonation occurs when air/fuel reaches too high a pressure. Since intake air here is only at 80% of sea level atmo pressure, at the top of compression stroke the max pressure is only 80% of what it would normally be. So less ping, but less power. It's like running a turbocharger backwards...

I'm not sure what a multiple sewing machine tick is. Do you mean one cyl vs several? If so, I'd say several.

 

91 is all we actually need for octane, exhaust leaks typically quiet down with heat. You could have a lifter tick, but they are usually either constant or heat related, worse with heat.