Discovery engine rattle

Submitted: Monday, Feb 18, 2008 at 20:09
ThreadID: 54706 Views:7076 Replies:16 FollowUps:23
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G'day people, I am seeking some mechanical advice. I own a '99 Landrover Discovery Series 1 with a 3.9L V8 which I have converted to LPG. I bought this vehicle 18mths ago when it had about 95k on it and it now has about 140k. It has been a very reliable vehicle except for a persistent engine noise that started at about the 120k mark.

When the noise first started, it was identical to the traditional ‘lazy lifter’ noise i.e. a light tappet noise would just clack for a second or so when the engine was first started from cold, then totally disappear. I assumed it was a lifter and did nothing. It progressively worsened over the next 10k to the point where it started appearing at all engine temperatures when the engine was put under heavy load (hard acceleration or towing a heavy load) from about 2800rpm upwards.

After worsening a little further I got the stethoscope out to determine the exact location of the noise. At this point I could make the noise appear just by giving the engine a quick rev. It appeared to be the top of the engine (it sounded obviously like a tappet) at the rear of the engine on the right bank. At this point, I dismantled the top of the engine including the inlet manifold and the rockers, pushrods and lifters. I inspected:
• the tops of the valves – no excessive wear
• rockers & shaft – no excessive wear
• pushrods – all straight and no excessive wear
• lifters – no excessive wear (which should indicate no excessive wear to camshaft lobes??)

I did note, however, that there was a fair build up of sludge in the top of the head and the rocker covers which indicated that the engine may have suffered from a lack of oil changes and perhaps short runs. I replaced all the lifters assuming that one had either failed or was blocked up with sludge. Upon reassembly I was disappointed to find that this made absolutely no difference to the engine rattle.

I drove the car for another 10k and though it worsened slightly, it didn’t appear to make much difference. The rattle is very obviously at the back of the engine on the right bank and is absent if the engine speed is increased slowly (no load) and if it is suddenly decreased from high speed, the rattle is quite loud. It also appears now at a much lower engine speed than it used to when under load and is louder than before. I considered the possibility of broken or weak valve springs so I recently removed the right rocker cover, tappets and pushrods and re-inspected.

Slight wear was apparent on the rear most rocker where it contacted the valve was apparent but not excessive. I removed every valve spring on the right head and inspected carefully. There were no broken valve springs or any that were significantly weaker than the others. The only discovery of note is that there were two oil feed holes in the top of the head for oil feed to the rocker shaft. They are under the front and rear most rocker shaft mounting posts. When compressed air is applied to the front one, it escapes into the sump through the oil gallery. The rear one, however, appears to be blocked. It doesn’t appear to be clogged; it just doesn’t continue past the head. The Haynes workshop manual I have has an oil feed diagram and only shows an oil feed to the front of the rocker shaft - none to the rear. Therefore, I must assume that the rear hole is not supposed to go anywhere.

I cannot explain the tappet noise. Numerous other mechanics have listened to the noise and agree that it is actually a tappet.

The only thing I have not done is remove the camshaft and inspect the lobes for wear, but I must assume them to be ok since the bottom of the old lifters showed no significant wear. There is no obvious wear in the rockers, valves, pushrods and the lifters have been replaced. I don’t know where to start looking now. Can anyone help?
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Reply By: Eric Experience - Monday, Feb 18, 2008 at 20:59

Monday, Feb 18, 2008 at 20:59
Mark.
Sounds like piston slap. do a compression test to check for a cracked piston. If the compression is good go for a loose piston pin or even big end. Eric
AnswerID: 288214

Follow Up By: markp - Monday, Feb 18, 2008 at 21:07

Monday, Feb 18, 2008 at 21:07
Thanks Eric, I have done a compression test and found all cylinders within 15psi of each other and within spec, so no concerns there. I suggested piston noise to 3 different mechanics who listened to the noise and all said No - definitely too high and too light to be piston. All said that they would swear it is tappet noise. Eventually, I will have to rip the head off and have a look if I can't find the problem elsewhere but it is a last resort.
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Reply By: garrycol - Monday, Feb 18, 2008 at 21:07

Monday, Feb 18, 2008 at 21:07
I susoect it is tappet noise caused by sticking lifters which is not uncommon in these engines - I understand there is an an additive that can be added to the oil that may assist.

Try the AULRO website at http://www.aulro.com/afvb/index.php - these guys will have the answer.
AnswerID: 288218

Follow Up By: markp - Monday, Feb 18, 2008 at 21:09

Monday, Feb 18, 2008 at 21:09
Thanks Gary, I tried a few different addatives to 'unstick' the lifter and eventually replaced all lifters but this still didn't fix the problem. So that's not it.
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FollowupID: 553486

Follow Up By: pop2jocem - Monday, Feb 18, 2008 at 21:15

Monday, Feb 18, 2008 at 21:15
Have you tried removing the rocker gear and tapping the ends of the valves to see if any are sticky?
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Follow Up By: markp - Monday, Feb 18, 2008 at 21:21

Monday, Feb 18, 2008 at 21:21
Yep, I recently removed all the valve springs on that (right) side and checked for broken springs and worn or sticky valve guides - all ok.
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Reply By: Eric Experience - Monday, Feb 18, 2008 at 21:19

Monday, Feb 18, 2008 at 21:19
Mark.
You say the noise is louder under load. a tappet is the same regardless of load. Check if the noise is load dependant if it is it is the piston. Eric
AnswerID: 288220

Follow Up By: markp - Monday, Feb 18, 2008 at 21:28

Monday, Feb 18, 2008 at 21:28
Very good point Eric, I hadn't really considered that. The noise is associated with noise but also occurs on deceleration. As I said, the noise seems too high in the engine and too high in pitch to be associated with a piston. If it was say, a very small fragment broken off the top of a piston, what would happen to the fragment? Do you think it would disintegrate and exit the combustion chamber? If the fragment stayed in the combustion chamber, wouldn't it rattle all the time no matter the engine speed or load? Also, wouldn't you think piston damage would affect the compression? I have compression tested the engine only to find that all 8 cylinders are within 10-15psi of each other and over 130psi. This is within spec.
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Follow Up By: markp - Monday, Feb 18, 2008 at 21:29

Monday, Feb 18, 2008 at 21:29
Sorry. Sentence should read: The noise is associated with LOAD but also occurs on deceleration.
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Follow Up By: Nav 8 - Tuesday, Feb 19, 2008 at 11:00

Tuesday, Feb 19, 2008 at 11:00
Possibility is a crack in the piston skirt. This will not effect the compression and will sound very much like a tappet or lifter noise. The noise can also come and go with different engine revs. Regards Nav.
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Reply By: Eric Experience - Monday, Feb 18, 2008 at 21:56

Monday, Feb 18, 2008 at 21:56
Mark.
As I said in the first post if the compression is good look at the bearings. To check a bearing get some one to hold a piece of 6mm rod against the piston [spark plug hole] when the piston is half way up the bore, then with a dial gauge against the ring gear measure the rotation before the piston moves. Good Knight. Eric.
AnswerID: 288225

Follow Up By: markp - Tuesday, Feb 19, 2008 at 19:18

Tuesday, Feb 19, 2008 at 19:18
Thanks Eric I will try that in my future diagnosis before I do anything major like removing the heads - but it is sounding like sleeves to me which will require stripping
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FollowupID: 553648

Reply By: Philip A - Monday, Feb 18, 2008 at 22:00

Monday, Feb 18, 2008 at 22:00
I hate to say it, but it sounds like a loose sleeve to me.
Does the car use water?
Usually a moving sleeve happens after the car has been overheated.
The problem arises from the way Rover V8s are made. The sleeves are pressed cold into a hot block onto a ledge in the block. Sometimes as they cool the sleeve lifts off the ledge. It is then machined flush to the deck. The head gasket fire ring is outside the sleeve, so if it becomnes loose the sleeve can move up and down between the head and the ledge, and it is loudest under load.
This usually is accompanied by pressurised cooling system, as the looseness is usually caused by overheating and a crack forming in the block behind the sleeve. ( but not always)

The only fix is to resleeve the block with stepped sleeves, which are sealed with loctite and the head gasket fire ring sits on the step.
Regards Philip A
AnswerID: 288227

Follow Up By: markp - Monday, Feb 18, 2008 at 22:12

Monday, Feb 18, 2008 at 22:12
Thanks Phillip, I must plead ignorance and admit that I know very little about sleeved petrol engines so your post was quite informative. The car doesn't use water, nor run hot but that's not to say that it hadn't been overheated before I bought it. I read a UK based forum that had numerous instances of this exact problem with no solution offered so I am guessing it is some unusual peculiarity of this engine just like you suggest. In your experience, with the head removed, is this problem reasonably obvious? Is it possible to get movement out of the sleeve by hand usually (again with the head removed). If I adopt your suggested repair method, I presume that I would need to do a full rebuild including all sleeves, pistons, rings etc? If so, it seems that it may make more economical sense to buy a changeover reconditioned engine or some other similar option as I imagine that the parts required would as expensive! I assume that the stepped sleeves you mention are a non-genuine part? Can you also suggest a potential supplier?
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FollowupID: 553510

Reply By: Member - Matt (Perth-WA) - Monday, Feb 18, 2008 at 22:23

Monday, Feb 18, 2008 at 22:23
Mark you have a few suggestions apart from the lifters and while suggesting piston skirt cracked or gudgeon pin I though...have you checked the exhaust gasket on that bank?

I know its a long shot but a tiny exhaust leak sounds exactly like a tappet noise and would increase with time. Just about everything you have described.

Goodluck with it mate.

Matt.
AnswerID: 288232

Follow Up By: markp - Tuesday, Feb 19, 2008 at 19:23

Tuesday, Feb 19, 2008 at 19:23
Thanks Matt, I have experienced an exhast leak like this before and the only thing that makes me reasonably certain it wouldn't be an exh leak is the fact that it rattles on deceleration whereas an exh leak would never do that I don't think. I will check to cross it off the list anyway though. Cheers.
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FollowupID: 553650

Reply By: Philip A - Monday, Feb 18, 2008 at 22:32

Monday, Feb 18, 2008 at 22:32
It is I understand at least 2K to have the sleeves fitted, plus rebuild. You will not get much change out of 5k , maybe more unless you do all the labour yourself.

Sometimes it may be better to buy a second hand engine but of course they may have the same problem.
Where are you?
In Melbourne Ritters or LRA should know and in Sydney Bruce Davis.

I have never had it happen , but you cannot move them by hand usually.
Sometimes the sleeve will sit proud of the block by a couple of thou, and you can catch it with a fingernail.
First I would take it to a Rover specialist like Ritters or LRA for them to give an opinion.
Mine is noisy when cold and I think it is piston slap But maybe I have a loose sleeve too! Alloy engines seem to amplify noise compared to iron .
Seeing the heads are not handed they have a drilling at each end,but only one meets an oilway in the block for the rockers
Regards Philip A
AnswerID: 288234

Reply By: Andrea11 - Monday, Feb 18, 2008 at 22:37

Monday, Feb 18, 2008 at 22:37
Hello Mark,

We have a 99 Petrol/LPG 3.9 V8, Landrover Discovery that has done 170000ks and 4 weeks ago we noticed a ticking noise when the engine was idleing. We took it to a Landrover Service Centre and they suggested it could be either Lifters or worst case scenario more dire a big end bearing or a loose bore cylinder sleeve and quoted us approx between $5000.00-$7000.00 to rebuild the motor. As it turned out we took it to our Mechanic who has stripped the motor and found 2 sleeves that had worked loose, and he is currently rebuilding the motor and has quoted approx $4500.00. I hope I haven't scared you too much, but the silver lining to this black cloud is that we will have a motor that will not need much doing to it for at least 10 yrs.

Good Luck
Andrea
AnswerID: 288236

Follow Up By: Andrea11 - Tuesday, Feb 19, 2008 at 13:55

Tuesday, Feb 19, 2008 at 13:55
FYI,

Went to the Mechanic today, he has also had to replace the pistons on our motor.....He suspects after talking to another Landrover owner and Mechanic that the cause of all of this was the LPG. Apparently when the bore sleeves were replaced he also got them pinned in so apparently we should never have a problem again with it.

Andrea
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FollowupID: 553584

Follow Up By: markp - Tuesday, Feb 19, 2008 at 19:10

Tuesday, Feb 19, 2008 at 19:10
Hi Andrea, thanks for the feedback. I would've thought that replacing the sleeves goes hand in hand with replacing pistons and that would've been a given. Does your mechanic that is blaming the LPG for this problem have much experience with this engine? I would be surprised if this is a consequence of LPG fuel rather a design weakness that perhaps fails as a consequence of running hot or overheating the engine. It makes sense to me that when the engine is an ALLOY block with IRON sleeves which are two different metals and have different expansion & contraction rates that this has potential to cause a problem when the engine is overheated. I would be interested in hearing if there is anyone who has had this 'loose sleeve' problem with a Land Rover that does NOT use LPG.
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FollowupID: 553645

Follow Up By: Andrea11 - Tuesday, Feb 19, 2008 at 20:45

Tuesday, Feb 19, 2008 at 20:45
Hi there Mark,

Apparently putting new pistons in don't go hand in hand with bore sleeve replacement just new rings and bearings. Our mechanic wondered if because gas is dry that the engine may get warmer than what it would with petrol therefore it could quite easily cause this problem. All I really know is that it is an expensive excersize but we were assured today we would have a new motor.

Andrea
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FollowupID: 553669

Reply By: Member - DAZA (QLD) - Monday, Feb 18, 2008 at 22:38

Monday, Feb 18, 2008 at 22:38
Hi Mark

We used to own a Range Rover, that had a rattle noise, we had
it serviced by Rover Mechanics, and we decided to get the heads
done as we suspected a problem with one of the head gaskets,
when they pulled them down, and inspected all the running gear,
they found one of the cam followers had been causing the rattle noise.

Cheers
Daza.
AnswerID: 288237

Reply By: Philip A - Monday, Feb 18, 2008 at 22:38

Monday, Feb 18, 2008 at 22:38
By the way the injectors can also make a noise and this is louder when under load.
Maybe also have the injectors cleaned and see if there is any difference, as if you are not losing water its less likely to be a sleeve than something else, however you have covered the usual culprits.

You know it can also often just be simply a blown gasket on an exhaust port to manifold or where the cast manifiold meets the downpipes. This is a definite candidate, seeing it gets louder under load.
I would do the cheaper things before embarking on a teardown.
Regards Philip A
AnswerID: 288238

Follow Up By: markp - Tuesday, Feb 19, 2008 at 19:21

Tuesday, Feb 19, 2008 at 19:21
Thanks for all your replies Phillip, I have learnt much and everything you have posted makes sense to me. I will check some of the more basic things now that I have many suggestions thanks to replies on here but eventually sounds like major works will be required. I did note that Andrea's mechanic had the machine shop pin the new sleeves which sounds better than just loctiting them in. Do you agree?
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FollowupID: 553649

Reply By: Member - Doug T (FNQ) - Monday, Feb 18, 2008 at 22:38

Monday, Feb 18, 2008 at 22:38
I would suggest a simple matter off adding some Wynnes or Nulon to the oil at each service, I practice what I preach and my Landcruiser now shows 718,000+ Ks and runs like a dream .....touch wood.

Wynnes Website

Nulon Website

,
still going strong with 836,179 K's

Lifetime Member
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AnswerID: 288239

Follow Up By: Steve - Tuesday, Feb 19, 2008 at 14:08

Tuesday, Feb 19, 2008 at 14:08
which one Doug?

Spitfire diesel additive?

whatabout a drop of metho?
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FollowupID: 553588

Follow Up By: Member - Doug T (FNQ) - Tuesday, Feb 19, 2008 at 14:26

Tuesday, Feb 19, 2008 at 14:26
Steve
Spitfire in the car and the Metho.......in you

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Follow Up By: Steve - Tuesday, Feb 19, 2008 at 16:11

Tuesday, Feb 19, 2008 at 16:11
I've had the metho on me cornflakes this morning ;-)

but really, was it spitfire for diesel engines you were talking about?

and

have you not heard of putting metho in with the fuel? Apparently evaporates water in the tank and cleans it at the same time - wondered if you felt you'd had any benefit from that. Some of these commercial fuel additives are apparently little more than metho - depending on what it's job description is.
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Follow Up By: Member - Doug T (FNQ) - Tuesday, Feb 19, 2008 at 16:22

Tuesday, Feb 19, 2008 at 16:22
Steve
If you had the metho on the Cornflakes you should be spittingfire.
No mate Spitfire is for fuel , you need Supreme Friction proof




Or better still this Nulon of which I will use from next oil change



.

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Reply By: Keith_A (Qld) - Monday, Feb 18, 2008 at 22:52

Monday, Feb 18, 2008 at 22:52
Hi Mark - Had a similar noise in my Patrol - turned out to be the air filter "rocking" on its base. Sounded like piston/big end ...etc but very hard to isolate. Perhaps remove your air filter and listen - you could be lucky - like I was......................Keith
AnswerID: 288241

Reply By: Smudger - Tuesday, Feb 19, 2008 at 00:55

Tuesday, Feb 19, 2008 at 00:55
Mark,
I'll be watching this post with interest to see what you finally diagnose.
My 97 series I has been on LPG since delivery to it's original owner. It's now done 220,000 and is strong as an ox, but has developed a most uncharateristic (for Discovery) throaty V8 sound over the past 2 years. No loss of power, performance, economy or extra use of oil. My mechanic can't figure it, but he did talk me into installing a "valve saver' oil resevoir, which I'm sure you're familiar with. He claims that the valve seats are wearing and the valves are seating marginally lower in the ports, but even a small margin is enough to cause loss of efficiaency in the lifters. The valve saver is supposed to help reduce wear in the valve seats. he also reckons LPG causes wear premature wear of valve guides. He's quoted me 2k to rebuild the heads.
I have no reason to do that yet, as I said the car just sounds sexy, and is behaving really well.
It's late, I'm not going to bother spell checking this, coz I'm going to bed. Hope it's a useful contribution. Keep us posted.
g'nite!
AnswerID: 288250

Follow Up By: markp - Tuesday, Feb 19, 2008 at 19:33

Tuesday, Feb 19, 2008 at 19:33
Smudger, thanks for your interest. I have been really thankful for all the people that have given of their time, wisdom and experience to reply to my post. I have a few suggestions to check before a major strip down of the engine which seems inevitable at this point. I will have to wait about four weeks to disable the car so that I have a work car to get about in but I will return to this forum and post what the final diagnosis ends up being. I would've thought your sexy note that your Landy has developed would simply be an exhaust baffle that has deteriorated but must be a different noise to what I am imagining. If the valves are seating lower in your engine as you say, then that should serve to DECREASE the valve clearance rather than INCREASE it to the point where it rattles. I am familiar with the upper cylinder lubrication kits available for LPG fuelled engines but have always been of the opinion that since the advent of unleaded fuel, engine manufacturers have been using much higher quality material for their valves and seats because of the absence of the lead in the fuel to act as a lubricant for the valves/seats so therefore, upper cylinder lubrication is of little value for valve/seat longevity. Anyway, I will let you know how it goes!
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FollowupID: 553654

Follow Up By: Smudger - Wednesday, Feb 20, 2008 at 00:04

Wednesday, Feb 20, 2008 at 00:04
I've had 4 different mufflers fitted and the current is a Land Rover original. Still sounds sexy, which is very un-Disco.
Where are you situated? My mechanc is a wizard and I would recommend him. If you're in Sydney he would be worth talking to.
He's the only mecanic who's quoted me on a job, and when I've collected the car told me his diagnosis was wrong and instead of the grand he quoted, presented me with a billl of less than a ton.
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FollowupID: 553724

Reply By: Fazz - Tuesday, Feb 19, 2008 at 10:11

Tuesday, Feb 19, 2008 at 10:11
Mark,
as a few have mentioned earlier," loose sleeves" it is a very common problem with the alloy V8.
You may not experience any lose of water with this problem as the sleeve does not have to move far to create the noise, still allowing the seals to do their job.

Cheers,
Fazz
AnswerID: 288276

Follow Up By: markp - Tuesday, Feb 19, 2008 at 19:35

Tuesday, Feb 19, 2008 at 19:35
Cheers Fazz! Do you know of any alloy V8 'loose sleeve' problems that have occurred in NON- LPG fuelled engines?
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FollowupID: 553655

Follow Up By: Fazz - Wednesday, Feb 20, 2008 at 14:30

Wednesday, Feb 20, 2008 at 14:30
Mark,
sorry for the delay, have been away.
The loose sleeve syndrome is not selective, it will happen to any set up.
Re read your first posting & you did mention that the noise went away once the engine had warmed up?
That is more than likely piston slap, it is also another common Range Rover/Discovery scenario!
I would not worry unless the noise gets louder & is happening when the engine is warm!

Cheers,
Fazz
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FollowupID: 553774

Reply By: Mal58 - Tuesday, Feb 19, 2008 at 15:18

Tuesday, Feb 19, 2008 at 15:18
Hi Markp,
A bit of a long shot perhaps. I had a 1967 Mazda 1500 as my first car.

I had few problems with it, but one that I remember well was that it had a sticky valve.

The sticky valve was intermittent, but when it was "bad" it would "clack" quite loudly.

Perhaps you have a sticky valve caused by running on LPG.

Have you tried any of the valve lube products for LPG vehicles ? This may help.

Cheers,
Mal

AnswerID: 288303

Follow Up By: markp - Tuesday, Feb 19, 2008 at 19:16

Tuesday, Feb 19, 2008 at 19:16
Thanks Mal - see above, I have checked valves & guides for wear and sticking
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FollowupID: 553646

Reply By: Philip A - Tuesday, Feb 19, 2008 at 19:59

Tuesday, Feb 19, 2008 at 19:59
FollowupID: 553649 Submitted: Tuesday, Feb 19, 2008 at 19:21
markp posted:
Thanks for all your replies Phillip, I have learnt much and everything you have posted makes sense to me. I will check some of the more basic things now that I have many suggestions thanks to replies on here but eventually sounds like major works will be required. I did note that Andrea's mechanic had the machine shop pin the new sleeves which sounds better than just loctiting them in. Do you agree?

If you have stepped liners fitted there is no need to pin the sleeves, as the head gasket fire ring holds them in place.
The loctite product is a seal to stop water leaaking down or up from possible cracks behind the sleeves.
Stepped sleeves are more expensive than other methods but to me seem the most reliable answer. And this seems to be supported by experience of rebuilders here and in the UK.
Regards Philip A
AnswerID: 288346

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