Disco 3 (LR3) What's with the knocking??

hoopfish · Mar 8, 2023

https://youtube.com/shorts/MgX8cqLMz74?feature=share

It has been slow to start in the mornings with a puff of white smoke. Stopped at some traffic lights today, put in neutral and started to make a funny noise. Then had this noise when stopping and pulling away, but it went away around the 30mph mark. Any ideas please?. Taking it in to the garage in the morning but not sure if I should drive it?.

freelance · Mar 9, 2023

Doesn’t sound good, what was it, cracked inlet manifold?

gstuart · Mar 9, 2023

Plus 1 in not sounding great , was wondering if maybe it’s an injector letting by, fingers crossed it’s a simple fix mate

personally to be on the safe side would get it taken to the garage on a flat bed

plse let us know how u get on

lynall · Mar 9, 2023

Kin hell, I would not be running that never mind driving it!
Think Gary has it right with get it recovered in.

hoopfish · Mar 11, 2023

OK chaps. I had it recovered on a truck yesterday, they rang within a couple of hours. 1 of the injectors has let go and they think that at least 2 more are practically dead. They have sent them off to be tested so should know by Tuesday how many need replacing. I'm thinking of just getting them all done whilst they have it in. These guys are the garage that I have always used since owning the Disco, they are about 15 miles from my house and can be a bit of a pain in the arse to get to them, so whilst I was waiting for a recovery to be sorted I had a mechanic from a local independent take a quick look at it. He knew exactly what was wrong with it...either...the chain at the back of the engine has gone, which would mean a replacement engine, about 4.5k to do. Or it is the rockers that have destroyed themselves, seen this many times before, be about 3.5k to repair and possibly more once he starts to take it apart. BUT bloody good news for you though, my dad is selling a manual LR3 same age, same colour and only wants 4k for it!. Amazing luck eh. Chain at the back of the engine?.

DiscoRay · Mar 11, 2023

So although he said he knew exactly what was wrong with it he came up with two possibilities that anyone could have guessed at and then tried to sell you another unknown vehicle. Not sure I would be using that guy in the future. If yours is an otherwise good vehicle then spend a few quid and stick with it, better the devil you know.

Nodge68 · Mar 11, 2023

That's no chain, and there isn't one at the back of the engine anyway.
Sounds like a spun rod bearing to me, or maybe even the crank just about to let go.

lynall · Mar 11, 2023

Nodge68 said:
That's no chain, and there isn't one at the back of the engine anyway.
Sounds like a spun rob bearing to me, or maybe even the crank just about to let go.

Both cylinder heads have a camchain, drivers side is at the rear and pasenger side is at the front.

Nodge68 · Mar 11, 2023

lynall said:
Both cylinder heads have a camchain, drivers side is at the rear and pasenger side is at the front.

Yes I forgot that the cylinder heads are reversed from side to side.

That's no timing chain noise though.

lynall · Mar 11, 2023

hoopfish said:
OK chaps. I had it recovered on a truck yesterday, they rang within a couple of hours. 1 of the injectors has let go and they think that at least 2 more are practically dead. They have sent them off to be tested so should know by Tuesday how many need replacing. I'm thinking of just getting them all done whilst they have it in. These guys are the garage that I have always used since owning the Disco, they are about 15 miles from my house and can be a bit of a pain in the arse to get to them, so whilst I was waiting for a recovery to be sorted I had a mechanic from a local independent take a quick look at it. He knew exactly what was wrong with it...either...the chain at the back of the engine has gone, which would mean a replacement engine, about 4.5k to do. Or it is the rockers that have destroyed themselves, seen this many times before, be about 3.5k to repair and possibly more once he starts to take it apart. BUT bloody good news for you though, my dad is selling a manual LR3 same age, same colour and only wants 4k for it!. Amazing luck eh. Chain at the back of the engine?.

Maltings land rover on ebay seem to be the best price for injectors, I did all six on mine a few years back.
99 percent of the time you send and injector to a pump shop, they will says its dead.

When the chain breaks the engine stops as it locks up as valves hit the pistons.

lynall · Mar 11, 2023

Nodge68 said:
Yes I forgot that the cylinder heads are reversed from side to side. That's no timing chain noise though.

No its dead injector/s, see his update above.

Nodge68 · Mar 11, 2023

lynall said:
No its dead injector/s, see his update above.

It's un unusual noise for a dead injector too, unless it's over fueling causing knock. A truly dead injector just causes it to drop a cylinder, making the engine appear to misfire slightly, which is what happened to mine when an injector failed out the blue. There was no knocking sound, just a drop in power and in instability of the engine when idling or accelerating.

lynall · Mar 11, 2023

Nodge68 said:
It's un unusual noise for a dead injector too, unless it's over fueling causing knock. A truly dead injector just causes it to drop a cylinder, making the engine appear to misfire slightly, which is what happened to mine when an injector failed out the blue. There was no knocking sound, just a drop in power and in instability of the engine when idling or accelerating.

Common rail crap, I reckon they are good for 100k at best in small engines, I think mine did 120k and the last 10k was smoky/uneven idle/subtle misfire cold start, it was the uneven cold idle that made me change them as I cold see it overloading a cylinder or two on and engine with a crank issue at the best of times!

Nodge68 · Mar 11, 2023

lynall said:
Common rail crap, I reckon they are good for 100k at best in small engines, I think mine did 120k and the last 10k was smoky/uneven idle/subtle misfire cold start

I'd agree. Actually I don't think much of reconditioned injectors either. I've got similar symptoms on my FL2 at the moment, so I've got 1 going down.
They're not too expensive to replace with new Bosch units, if they come straight from a good Bosch main agent.

hoopfish · Mar 11, 2023

Nodge68 said:
It's un unusual noise for a dead injector too, unless it's over fueling causing knock. A truly dead injector just causes it to drop a cylinder, making the engine appear to misfire slightly, which is what happened to mine when an injector failed out the blue. There was no knocking sound, just a drop in power and in instability of the engine when idling or accelerating.

Yes it is over fuelling which was causing the knock!.

lynall · Mar 11, 2023

Nodge68 said:
I'd agree. Actually I don't think much of reconditioned injectors either. I've got similar symptoms on my FL2 at the moment, so I've got 1 going down.
They're not too expensive to replace with new Bosch units, if they come straight from a good Bosch main agent.

Various bits I have read suggest you cannot get spares for most of the common rail injectors, so a recon must be a strip/clean/adjust send back out again.

gstuart · Mar 12, 2023

Double post

gstuart · Mar 12, 2023

hoopfish said:
Yes it is over fuelling which was causing the knock!.

Yah, well that wasn’t a bad guess me mentioning about the Injectors, I must be getting better lol

Of course nowhere near the level of the other guys here ,

Out of curiosity what year is ur D3 plse as I know there’s a difference with the injectors according to year , hope u get it sorted out mate

hoopfish · Mar 16, 2023

gstuart said:
Yah, well that wasn’t a bad guess me mentioning about the Injectors, I must be getting better lol

Of course nowhere near the level of the other guys here ,

Out of curiosity what year is ur D3 plse as I know there’s a difference with the injectors according to year , hope u get it sorted out mate

Better guesses on here than from my local independent!. Its a 07 plate. Still waiting to hear back from the garage, they sent them off on Saturday to be tested, then any knackered ones will be refurbished and put back in.

gstuart · Mar 16, 2023

hoopfish said:
Better guesses on here than from my local independent!. Ita 07 plate. Still waiting to hear back from the garage, they sent them off on Saturday to be tested, then any knackered ones will be refurbished and put back in.

many thks and so pleased it wasn’t anything more serious and the advice was useful to u

Plse don’t think I’m trying to teach u how to suck eggs and expect u know already but indeed the 2007 onwards had different injectors , HPFP etc , along with the weaker oil pump casing, hopefully that’s already been replaced with the upgraded one

Indeed such a fantastic forum full of very knowledgeable people , alas I’ve still got a lot of catching up to do , fingers crossed it’s all sorted sooner rather than later

Disco 3 (LR3) What's with the knocking??

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