help with td4 top end knocking......Please......

Got a knocking on my engine comming from top end. Starts at around 2000 rpm. Goes around 3500rpm.
Before and after that engine sounds sweet.
Removed injector plugs one at time and found knocking goes when number two is removed. So i swapped number 2 injector for number 4 hoping the knocking would move to number 4, but its stayed with number 2 but still disappears when you remove the injector plug.
It sounds like a loud diesel knock.

Anyone any ideas as i,m due to go on holiday with it in a couple of weeks.

Thanks
Richard.

I can't help on this I'm afraid. Hope someone's got some advice for you as you haven't had any feedback on your posts.

Mileage? Have you tried some injector cleaner, have you replaced dodgy injector, sounds like it's already done the damage, hole or cavity in top of piston can sound like a diesel knock, what was fault with injector?

I would first try some serious dose of fuel additive / cleaner. Before condemning issues such as top end (little end) etc - (unlikely due to decrease at higher revs!) - I would seriously suspect sticking piston rings in cylinder 2 - not at all unusual ! - and honestly - I would not worry at this stage beyond that - DEFINITELY not a hole in the piston or cavity (Sorry Freelance mate)

Get as much cleaner through the system as you can . !
also - replace injector 2 REGARDLESS of results of swapping with 4 etc - swapping will not make any difference short term with sticking rings - but - will make long term difference. A leaking injector on 2 would cause the issue.

So my advise - stuff it full of fuel cleaner (within limits of course and don't exceed the manufacturers dosage!) and - best quality diesel ! - Defo !!!! change injector 2 for another - regardless.
Probably be ok - absolutely ok ! - the knock you describe seems to be - on first impressions along with the tests you have described - as simple stuck rings caused by a leaking injector over a period of time. (carbon build up!) - the rev range is the added load of turbo kicking in addition to the probable (and likely) issue of the stuck rings - if little end related it would be there all the time from the first load and upwards (very very unlikely!). - also valve seal issues unlikely at this stage !

DEFINITELY Change the No. 2 injector for another (second hand one is ok) - not a swap to another cylinder ! - dose it with additives - use top quality fuel and use it for the holiday without worry.. only AFTER that - if issue continues AFTER THAT *unlikely* you possibly may be more concerned.

Hope that adds a modicum of reality and logical fault deduction. - ie - don't sweat it

Don't worry at all at this stage - dump injector 2 - literally ! - and replace it with S/H unit - and add the additives and top of the range fuel for a while.

Best wishes mate - I am sure you will be fine.. results will not be overnight but hopefully it will all be sorted. - do the above and go on holiday and enjoy - do not sweat it
Joe

I also doubt it is a hole in the piston I had one of those many years ago but petrol engine and the smoke that was behind me was like thick fog , it could be a bad injector that has been putting too much fuel through also have you changed your oil recently as old oil will not do the valves any good .hope this helps

I will firstly admit I dont know whats wrong, however I have spent years stripping engines and I am also a Rolls Royce manufacturing engineer on aero engines, so not an idiot.
So based on the principles of engineering and experiance, its not likely its a mechanical problem.
Once stripped a meastro with a top end knock, it had slipped a big end bearing and the piston was hitting the head.
Moving the injector would not have solved that issue.
A little end issue and to be honest I dont know the set up of the TD4 piston connection mechanics, but again moving the injector would not solve this issue either.
Knocking from a cam or valve is not something I have come across, it normally builds from a tap to a loud tap if ignored.
A hole in a piston causes all sorts of problems, simply removing the oil filler cap would see lots of pressure in the system.
I agree I would start by replacing the injector, I doubt its a mechanical issue.
Stuck piston rings, thats a compression test. I do a series of checks, test each cylinder. If they are in expected range, all good. If ones down, pour a good amount of oil down into the cylinder and repreat check, if the rings are stuck the oil will help seal the cyinder and give an improved compression check. If its a valve burnt out thevreading will remain the same.
hope some of that helps

Do you run it on supermarket fuel?

Have you done any work on the fuel system recently? I renewed my fuel lines on my p38 once and upon restarting it had an awful top end bang! It was trapped air that needed bleeding out via cracking an injector and running the engine. Ironically it too was number two...

Lowbank said:

I will firstly admit I dont know whats wrong, however I have spent years stripping engines and I am also a Rolls Royce manufacturing engineer on aero engines, so not an idiot.
So based on the principles of engineering and experiance, its not likely its a mechanical problem.
Once stripped a meastro with a top end knock, it had slipped a big end bearing and the piston was hitting the head.
Moving the injector would not have solved that issue.
A little end issue and to be honest I dont know the set up of the TD4 piston connection mechanics, but again moving the injector would not solve this issue either.
Knocking from a cam or valve is not something I have come across, it normally builds from a tap to a loud tap if ignored.
A hole in a piston causes all sorts of problems, simply removing the oil filler cap would see lots of pressure in the system.
I agree I would start by replacing the injector, I doubt its a mechanical issue.
Stuck piston rings, thats a compression test. I do a series of checks, test each cylinder. If they are in expected range, all good. If ones down, pour a good amount of oil down into the cylinder and repreat check, if the rings are stuck the oil will help seal the cyinder and give an improved compression check. If its a valve burnt out thevreading will remain the same.
hope some of that helps

Click to expand...

Hi Lowbank - great advice and observations there !.
I presume you were working for Rolls in Barlick ? - were you at BankField or Ghyll Brow ? (Barlick is my home town before retiring here to Portugal - my bride was born there mate !)
The home of the RB211 (Rolls Barnoldswick eh) - eee the days of testing the buggers at Ghyll ! yikes !
Did they ever collect all those 'ooops I polished too much off' titanium blades from the Canal below the back windows of the polishing shop (seriously!) haha
Anyway (apart from 'yay the Clarets !)

Now, as for compression tests on diesels, they can be funny beasts with stuck rings (usually carbon from a leaking injector) - in the event of piston slap, the compression test is sometimes down, yes (but not always), - but even if slightly down - often it is within the 'normal' allowable variation range.
The symptoms of piston slap are usually caused by a stuck ring that is designed to expand in the bore by the action of the force of the ignition (as opposed to a 'plain' ring. Symptoms are often as described, (if piston slap) - that the ring does not 'expand' sufficiently under load and causes a slap. - yet, on a static test of compression can read a relatively normal figure.One can of course, SOMETIMES expect some kind of noticeable blow-by but again - , it is a strange one to diagnose and certainly so at cranking speed levels)
Severe issues with rings will of course cause all the normal classic blow by / low compression etc issues - however slight issues on (relatively) modern diesels often cause very limited 'abnormal' diagnostic signs, but, manifest themselves in a quite noticeable piston slap.
Piston slap is one of the largest contributors of overall noise in a Diesel as opposed to petrol engines - it is inherent to the nature of the beast. Of course - most modern engines and control units attempt to 'design' this out as much as possible. However, even the slightest thing out of kilter on one pot can cause it to slap and be noticeable. (or indeed on all pots (as for example a sticky advance solenoid on an L series - which all the normal diagnostic tests come up totally negative but the diesel knock (piston slap) is horrendous)
I still stick with the previous advise - go for fuel additives / cleaners / and also high quality fuel for a while - definitely change the injector though. This kind of issue (If simple single piston slap) - is definitely not the easiest to diagnose by the normal methods - in fact - obtusely, the 'normal' diagnostic methods showing 'Absolutely no abnormal readings' can actually re-enforce the proper diagnosis as to the abnormality.
Ain't they good fun eh ?
You gotta luv em.....
Joe

Yes its Barlick, worked Bankfield. Now at Ghyll but will be moving back soon. The current plan is to knock Ghyll down and move everything to Bankfield.i have been lucky so far not to have to strip a diesel engine, I do have a project TD4 engine in the garage but so far have not had time to strip it.
Do you think you can unstick a piston ring with just additives, I have no experiance of this on diesels. I have stripped 4 stroke and two stroke bike engines that suffered from this and normally had to replace the rings.

Thanks for your replies. Took it round to my friends garage today and let him have a listen. It would seem that as well as number 2 injector making knocks, number 1 is as well as unplugging 1 removes the noise.
He suggested what some of you have said do a leak off test first and see what that brings up then go from there.

As i am too busy at work for next 2 weeks before i go away, we've decided to go in one of our other cars, which is a shame, as i like the freelander and have a deeper look into ot when we get back.

As an aside, if it turns out to be big end related, can the sump be dropped with engine in situ without dismantling too much.

Thanks
Richard.

on the freelander 1 you can drop the sump easily without too much work make sure you drop the oil first or you will get covered

richard.1969 said:

Thanks for your replies. Took it round to my friends garage today and let him have a listen. It would seem that as well as number 2 injector making knocks, number 1 is as well as unplugging 1 removes the noise.
He suggested what some of you have said do a leak off test first and see what that brings up then go from there.

As i am too busy at work for next 2 weeks before i go away, we've decided to go in one of our other cars, which is a shame, as i like the freelander and have a deeper look into ot when we get back.

As an aside, if it turns out to be big end related, can the sump be dropped with engine in situ without dismantling too much.

Thanks
Richard.

Click to expand...

Hello Richard, has he actually DONE a leak off test ? otherwise - we are again into contradictory diagnosis - one cannot want to do a leak off test and then say 'it turns out to be the big ends unless some serious fault finding has taken place. - Big end knock does not usually 'go away' at 3500 rpm' (although you are definitely in the max torque band from 2000 - 3500 !!)

Or it is the big ends, then removing the sump in situ can confirm the issue only - by removing the rod caps and half shells and examining both the shells and the crank journals. - NOTE - UNDER NO CIRCUMSTANCES CAN it be fixed in situ ( IF it is Big Ends / Crank) - In the case of a big end / crank issue then the whole engine would have to be stripped and examined to locate the reason. Lack of oil - bearing spin (unlikely but possible - and highly unlikely on two pots without serious other causality!)

If removing no.1 injector improve the issue - what happens when the injectors are swapped ?

Before committing to such a serious diagnosis - I would explore every avenue - you have had many people look and many diagnosis - of course - 1 may be totally correct. - it is however worrying that the diagnosis and action taken for such vary so significantly. !

In the event of a PROVEN issue with the crank - then simply get a replacement engine - it is just not financially viable to correct the issue (IF crank related)
You are talking a full and complete strip down- and total chemical and thorough block cleaning including ALL oil galleries !, new oil pump - possibly and probably a new crank ! - new bearings - big and main - all gaskets - probable cams and followers due to an oil pressure / circulation issue.. - simply no way cost effective - something is catastrophically wrong for such a diagnosis.

Has ANYONE definitely ruled out an issue with a hydraulic cam follower ?

I still find it extremely hard to believe a diagnosis of big end failure at this stage - obviously it cannot be ruled out ! -

What were your oil and filter change intervals and the actual mileage ???? - the lower the annual mileage the more frequent the oil and filter needs to be changed - also - cam belts every 4 / 5 years. - regardless of mileage.

Also, have you (or one of the 'mechanics' considered / ruled out timing belt issues such as jumping a tooth etc ? (which would definitely cause such issues- the timing belt is a mileage OR time dependent change item.

TELL them - that while you are away to first check the static cambelt ' timing of the engine. This is a must do test (unless they have some major diagnostic proof to definitely identify the cause) - easy test with extremely important results !

I would still you suggest you send a video with sound - from not too close - of the issue.
Joe.

Lowbank said:

Yes its Barlick, worked Bankfield. Now at Ghyll but will be moving back soon. The current plan is to knock Ghyll down and move everything to Bankfield.i have been lucky so far not to have to strip a diesel engine, I do have a project TD4 engine in the garage but so far have not had time to strip it.
Do you think you can unstick a piston ring with just additives, I have no experiance of this on diesels. I have stripped 4 stroke and two stroke bike engines that suffered from this and normally had to replace the rings.

Click to expand...

Hi mate, absolutely yes on the rings on the diesels - specifically with over fuelling ! - as opposed to gasoline engines (or two strokes) Diesel fuel is an extremely good lubricant and tend to be the reason why diesels last so long and do not tend to suffer from bore wear as opposed to gasoline. Whereas a gasoline engine relies on main engine oil for bore lubrication the diesel is heavily reliant on the fuel itself. In the event of ring issues causing slap, it tends to be a form of 'gum' caused by over fuelling as opposed to a hard carbon deposit, this can very often - and usually - be resolved if caught at an early stage by removing // repairing the source (usually the injector) - and then applying appropriate cleaning additives and higher quality fuel - on older diesels we used to add a small amount of gasoline to the tank also - however- not too applicable to modern units.
There is absolutely no need or benefit in using these 'so called better fuels' in everyday use - however, for the purposes of assisting cleaning with additives - they help.
Again I must stress, piston slap is inherent to the design of the diesel engine - modern ones only do their best to reduce it - one thing only slightly out in the system and you have it loud and clear.
Best regards mate
Joe

It's not unheard of for the TD4 to suffer crank failure. Which I understand in early stages can sound like diesel knock,until it bashes itself into complete failure.

hi joe,

no-one has actually diagnosed anything as i have been doing it myself, apart from when i took it to a friends, but we never did anything other than pull plugs off injectors, hence finding that number 1 was also causing and issue. he also mentioned that each injector has to be coded to the cylinder. so as it stands we have number 2 and 4 injectors swapped, and a noise that goes away with pulling number 1 off. a spluttering when turbo kicks in which may be down to the swapped injectors not being re-coded as it wasn't there before. i have yet to swap number 1 injector at the moment due to time issues but thats my next action and if the noise follows then problem solved, hopefully.

big end issue was merely a suggestion brought up by me, but there are a few things that are putting me off this. 1, if there was wear in the shells wouldn't there be a knock when first started until pressure builds up? the oil light goes off before i release the ignition key.2. the engine runs and sounds sweet up to around 2000rpm. and the fact that the noise disappears instantly at around 3500rpm where the engine gets a new lease of life.

doing a leak off isn't going to cost anything, and looking at the injectors, they have been off before and marked with tippex. ive only had the car since last november and it has now done 115,000miles. 6000 miles since last oil change. not sure wot you mean about cam belts, td4 has cam chain and i'm 100% sure it has not jumped a tooth.

i dont think its a cam follower as its to loud in my opinion.

will still do as you suggest and try some injector cleaner.

cheers

richard.

Sounds like injectors could be fouled or are failing.
They are not coded to the engine but they should really be fitted in balanced sets.

As @Nodge68 says, the injectors do not need coding in any of the Freelander 1 series.
Mike

P.S. Put a good glug of mineral two stroke oil into your diesel. Helps lube internal parts upto the injectors. Loads of us use it all the time with good results.

I have had a crank break on an MG BGT. strated her one morning and the clatter was ear splitting. Still drove it to my Garage which was a mile away. I could feel the mass vibrations through the clutch.
5 hours later engine out, sump off and cannot find a thing, undid the mains and big ends. found nothing. Rotated things etc, in the end spent two hours dropping it back in and firing her up to the same god awful noise. Two hours later back out and sump off, rotates the engine and a thin line of oil appeared on the crank. Fly wheel off and and mains and bigs undone. wey hey crank in two halves.
believe me you know its serious when the cranks broke, I was just amazed I missed it first time but it was a clean break, due to the crank reconditioners putting a false cut in the web.

Update.

Removed feed and return pipes and did a diesel purge with liqui-moly.ran for a minute and switch engine off and left for a day or so.

Removed injectors and stripped them down and put them in an ultrasonic bath.

Reassembled and refitted and ran the rest of the diesel purge through.

Refitted fuel pipes and new filter.

Knock has gone now and engine much better.

Total cost £15 for 1ltr diesel purge.


Thanks for all your assistance.

Richard.