Good evening all,

I've recently purchased a 1996 Discovery SD, 4.0L and am in the process of learning all about this thing as I go -so far it seems to be a very solid ride! I've stated in the member introduction page (with a few pictures if interested): Very clean body and frame, virtually no rust being a Florida vehicle. 97k miles. It needs a few things, which is to be expected. I've read a lot on these vehicles in the past, they've always been appealing to me yet I have never worked on one (always owned a cherokee). What I’ve noticed so far - the steering pump is wet (2 drops over night), rear main area is wet just aft of the oil pan, not dripping. Brakes seem ok. Possible driveline u joint needed, minor clunk clunk at sharp acceleration. Rear window switches don't work (don't care). Ignition is a little sticky but manageable. Seems to starve for fuel at start up. Takes a few on/off cycles to generate enough go to keep her running. So far from what I've gathered, by other members input – I’m going to check my shafts and start with a fresh oil change of 15w40 rotella and troubleshoot the fuel issue with a pressure gauge and take it from there (the fuel pump is in fact located under the cargo area carpet). My growing concern is I am having some trouble diagnosing an engine knock that seems to be intermittent. I noticed it the other night when I took it to get some gas and the engine was at operating temp. Naturally the knock increases with RPM. I just had it running in the driveway for 20min bringing it to temp and no knock or any noise whatsoever, gave it gas throughout all range of RPM and it seems to be a rapid knock once the RPMS get around 2000, back down to idle and it quiets. Not sure if that’s even a factor here. I did take a peak inside the oil fill port and saw this, someone please tell me that’s not my rocker arm hitting the valve cover…. What would cause this??

 

You won't see you rocker arms from that fill hole. Ever. These rigs have splash guards on the valve covers. Take your time diagnosing your knock. Thought my was a rod but ended up being a bad cat. Good luck!

 

Thank you so much for the help. I must have googled valve cover images in 10 different way to see an underside image or a fill port image. You just made my night! Apologies if that was an extremely novice assumption, I'm VERY new at this

 

The only dumb question is the one you don't ask. We have all been novices here at one time or another.

Your engine knock could be anything from a slipped liner to a fan belt. Since it comes and goes, I doubt it is a liner.or it would do it all the time. More than likely it is thin oil. Start with the oil change and have them look for metal filings in the oil. If it looks like metalflake paint, you got a problem! It is possible the oil is dirty enough to open up the bypass valve and is lowering your oil pressure.

Or it could be something rattling around in the exhaust. I had a muffler break a baffle and it would plug the outlet sometimes, sounded like the motor was going to blow up! Took the muffler off and it ran fine (just really loud) new exhaust and no problems!
These trucks like to run on higher octane fuel too. In Europe, regular gas has the same or higher octane rating than premium or super gasoline ( I think it likes around 97 octane rating) so maybe you got some cheap gas or gas that has a lot of alcohol (Ethanol) in it. (I stay away from that stuff if I can) as it can cause problems and drop your MPG.

Before going crazy on oil leaks, clean out all the built up gunk on the motor. It could be just dripping from someone doing a bad job of adin fluid and it takes it some time to drip off all the mud and built up gunk in the engine compartment. Plus it makes it easier to work on.

The 1996 uses the less expensive fuel pump, but make sure it is not an electrical problem I got my truck with a "bad fuel pump" from the previous owner, and towed it home. After replacing the fuel pump, it would work, then quit after I shut it off at a store parking lot only to have it not start when I came out. I would tow it home, and it would start up just fine. After 3 weeks of this, I finally figured out it was the wire connectors for the inertia switch under the hood, attached to the firewall. I cut the wires off and soldered the together and it has run fine for over a year! Still have the old pump as a spare, so you know it will never fail.
There is also a connector by the rear tire for the wiring harness to the fuel pump that is a common problem too.

Try a little lubrication on the ignition switch. I noticed mine works better if you push it in before turning it.

As I mentioned before on the U-Joints, most have a grease fitting on them and adding grease is never a bad thing to do. Especially the front drive shaft, rear u-joint as it gets hot from the exhaust. If that one breaks, the drive shaft still turns from the front wheels and will whip around smashing anything close by (like the transfer case)

I got new window switches for the console between the seats for $12 each on Ebay, made a big difference in how the back windows worked after I did the modification to make them work right.

https://landroverforums.com/forum/di...-bypass-73519/

 

Good morning all, I was able to get some of the bugs worked out over the past week or so. Ignition is cleaned up and working fine, shafts are greased, no play and clunking has subsided. shifting, running, idling fine.. I had changed the oil to 15w40 rotella and added some mystery oil. The engine seemed to have loved this and is idling smoother, yet the knock remains. I've driven the vehicle daily for the past week and everything has been great, idling 20 min plus with the temp just below half. The knock is rapid and noticeable at start up, leveling out when warm - I don't believe this is indicative of a slipped sleeve. The other night I went to get ice cream, leaving it idle in the lot. Drove home, stopped at the wash bay to clean her up and left her idle while doing so as well - keeping an eye on the temp. Never went above just below 1/2 gauge. Started driving home, the temp steadily climbed. I pulled over and could hear my coolant boiling. Shut it down, let it cool and restarted 45min later. Hard start, but ran with no overheat the entire way home. I've been researching where to begin with this for the past couple days and are all over the map. This knock is a major concern to me, could this be conducive to the overheat? I find it hard to believe. The oil is clean, not burnt and has no visible debris in it. I'm hoping this is an isolated situation and could have just been a stuck thermostat, as I have not replaced it yet. Any help, tips, or suggestions are more than welcome, I don't feel so hot at the moment

 

I had a knocking sound when my water pump bearings went bad.

 

I don't think the sound is coming from the water pump, and I feel if it were the water pump it wouldn't be circulating the coolant at idle or under load and would be running hot at all times, I believe there would also be coolant seepage - one of the above. The vehicle has been running strong aside from the one overheating episode. I'm just trying to determine whether the knock and the overheat are connected.. From my understanding a slipped sleeve will cause this, but I am experiencing knock at all times and no metal in oil and no coolant in oil. I'm starting to think chronic intermittent overheating may have been an issue for the previous owner, possibly causing the knock?

 

I had a 180F thermostat FWIW.

I did not have overheating problems, but it would run a little hotter than normal with that stat i.e. 195ish.

I did have coolant seepage from this. Another easy tell is the fan will have a noticeable wobble.

 

Knocking; rockers not receiving enough oil, exhaust gaskets - manifold, manifold to down pipe, olive between Y pipe and muffler pipe, spark jump under a boot to ground (you'd get a misfire code usually), timing chain slop, and I'm sure others can chime in on their experiences. You should run some Seafoam right before you do another oil change and don't rev engine, let it idle. Also check your PCV on your passenger valve cover - can cause hard starts and doesn't trip a CEL. The water pump is worn when you can lift up on the fan and the whole enchilada moves - fan and pump. Also check belt and pulleys for looseness.

 

I'm convinced this isn't an exhaust issue, it seems to coincide with RPMs too closely and coming from within the engine. The coolant hoses are soft during operating temp so my next step is to check the water pump and coolant pressure. The breather hose on the passenger valve cover was torn at the base and was replaced, oil separator insert cleaned at this time also. My concern is the knock at this point, I am worried that damage has been done by overheating. I've been researching my butt off and am trying to determine my next best route. Is there a sure-fire way to rule out a slipped sleeve? I'm worried I'm going to start throwing time/parts at a block that doesn't merit neither. My projects for the weekend include checking the coolant pressure and oil pressure. Does anyone have tips on checking the oil pressure?? I'm looking to install a permanent gauge if everything checks out ok.