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Slight knock under light load


Dogconker
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Well, I’ve been driving my car now for 60k and the last week or so I’ve noticed that there’s a slight knock coming from the engine, only dies it under light load so gentle accelerating up to about 2200rpm is quite noticeable but not at when off the throttle or when at full or heavy throttle.

Not feeling too comfortable about the outcome of this, knocking noises from a modern diesel can’t be a good thing!!

car is in tomorrow to get checked out.

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Will be interesting to hear the outcome. Hope it's not catastrophic, there certainly doesn't seem to be many story's of low mileage engine issues on XVs. 

Hope it's something easy.

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On 22/10/2017 at 8:29 PM, Swayze88 said:

Will be interesting to hear the outcome. Hope it's not catastrophic, there certainly doesn't seem to be many story's of low mileage engine issues on XVs. 

Hope it's something easy.

They say cam follower is most likely. That said they had to replace a BRZ engine the other week that had a crank knock, only done 18,000 miles. I guess there’s always going to be a few that have an issue, but the don’t generally break to be fair. It’s under warranty so I’m not too worried just st now.

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Well I drove mine this morning and it sounds like someone has emptied a bag of just an bolts into the engine, dealer still insists it’s nothing serious and it’s safe to drive as they think it’s outside of the block so not pistons, crank etc. They are just saying it’s rattling. 

My worry is I had a petrol engine make this noise about 30 seconds before it dropped a valve into the cylinder, piston shoved the valve head through the water jacket, filled the cylinder full of water and hydraulicked the head, that was then end of that engine.

just hoping now it’ll survive until Monday when I can leave it with them.

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Just read this, but sounds exactly like what my type r was doing when it spat the crank, about 2k had a slight rattle, well would have done had it not been stripped and found the bearings were shot.

anything like this?

 

 

 

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No it’s much more of a rattle, it literally sounds like there’s something bouncing around inside one of the cylinders. But it’s somewhere between s rattle and a knock. 

If im parked and rev the engine, it didn’t do it, if put my foot down hard it doesn’t do it, if I drive along a 40mph road normally, bucket of spanners. As I say last time I heard this a little while later it dropped a valve.

hopefully it is just a valve followed bearing or something causing it to rattle. Much worse when it’s cold too.

my fear is it won’t make it to Monday, there’s nothing on the internet about this so guess I got unlucky

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Is it still under warrenty?

Yes the drive train is under warranty until end of 2018, I’d probably buy a warranty after that to be fair.

XVs come with a 3yr unlimited warranty and then another 2yrs drive train warranty.

 

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I had a similar problem with a turbo 4 can legacy. It was the hydraulic valve lifters. I cured it with Wynn oil valve seal rejuvenator and several oil changes. It had been caused by the hydraulic valve lifters lacking pressure to maintain the valve clearance.

If you don't go over 3000rpm then damage is unlikely.

Your car is much newer so perhaps an oil change with a pre flush will cure it as the very tiny oil channel to that lifter may be a bit gunked up. 

I always change oil at about 5k, don't care what the dealer may say, diesels get dirty oil much faster than petrol engines so changing oil in between dealer service can only be a good thing in my book of car Zen.

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38 minutes ago, Aberdeen Chris said:

I had a similar problem with a turbo 4 can legacy. It was the hydraulic valve lifters. I cured it with Wynn oil valve seal rejuvenator and several oil changes. It had been caused by the hydraulic valve lifters lacking pressure to maintain the valve clearance.

If you don't go over 3000rpm then damage is unlikely.

Your car is much newer so perhaps an oil change with a pre flush will cure it as the very tiny oil channel to that lifter may be a bit gunked up. 

I always change oil at about 5k, don't care what the dealer may say, diesels get dirty oil much faster than petrol engines so changing oil in between dealer service can only be a good thing in my book of car Zen.

It’s been into the dealers, they said don’t worry about it it’s fine, they have no instructions about preserving the engine or anything. Though I’ve naturally I’ve taken it steady because the noise isn’t sorted my right with me. I’m not putting in any oils etc because it’s under warranty and I don’t want to give them an excuse not to honour the warranty.

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Absolutely agree,

I take an empty oil containers to the dealer and they fill them up with the correct havoline engine oil for me. The cost is actually less than me buying the oil myself from eBay etc.

They are happy for me to do interim oil and filter change, and because I keep the receipt I can prove I have used the correct oil should there ever be a problem.

I tow a caravan and a trailer in my forest off-road so the car gets extra hard work.

But perhaps doing extra oil changes is something to consider in the future once they have fixed the problem.

Personally I think the manufacturer oil change intervals are stretched a bit; since the deposits of carbon in the oil must cause more wear. Carbon being such a hard abrasive material and dealers and manufacturers assuming we only keep our cars for five years beyond which their not really interested in anything older.

A well cared for Scooby can last at least fifteen years in my experience, my plan is to have mine at least that. Thus the extra oil changes will pay off down the line. Also cleaner oil makes for a cleaner engine internally which gives strength to longevity.

Honestly changing the oil on an XV is about as simple as it gets!

I don't know many cars that can pull a trailer of 500kgs of logs up a muddy hill out of the woods with so little drama 😁

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2 minutes ago, Aberdeen Chris said:

Absolutely agree,

I take an empty oil containers to the dealer and they fill them up with the correct havoline engine oil for me. The cost is actually less than me buying the oil myself from eBay etc.

They are happy for me to do interim oil and filter change, and because I keep the receipt I can prove I have used the correct oil should there ever be a problem.

I tow a caravan and a trailer in my forest off-road so the car gets extra hard work.

But perhaps doing extra oil changes is something to consider in the future once they have fixed the problem.

Personally I think the manufacturer oil change intervals are stretched a bit; since the deposits of carbon in the oil must cause more wear. Carbon being such a hard abrasive material and dealers and manufacturers assuming we only keep our cars for five years beyond which their not really interested in anything older.

A well cared for Scooby can last at least fifteen years in my experience, my plan is to have mine at least that. Thus the extra oil changes will pay off down the line. Also cleaner oil makes for a cleaner engine internally which gives strength to longevity.

Honestly changing the oil on an XV is about as simple as it gets!

I don't know many cars that can pull a trailer of 500kgs of logs up a muddy hill out of the woods with so little drama 😁

Well mine’s got to pull 1500kg of caravan up the M6 soon 😳

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On 25/10/2017 at 10:58 AM, Tidgy said:

Is it still under warrenty?

Yes the drive train is under warranty until end of 2018, I’d probably buy a warranty after that to be fair.

XVs come with a 3yr unlimited warranty and then another 2yrs drive train warranty.

 

Whoops haha, not sure how I did that. 

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So Subaru now say that the noises are diesel knock caused by the injectors not running right, they seem to think it needed an injector relearn, which has now been done, certainly it went like stink on the way home but haven’t heard it when cold yet so not 100% yet, will soon find out tomorrow am

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Well whatever it was that they did it seems to have greatly reduced the knock/rattle, even when stone cold, so that was an easy fix. 

Thid the problem with having injectors that learn how you drive and adapt to it. Basically AI fit injectors.

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Maybe you got some bad fuel and it confused the system, or perhaps like all solid state stuff some of the memory just got corrupted.

I work fixing and rebuilding this kind of digital electronic systems and devices. Often turning it off and unplugging it for a couple of minutes causes the random access memory to discharge and forget the infinite loop of confusion it was caught up in, so allowing when reconnected again for the recalibration and clean refreshed running

I hope your Scooby's happy now 👍

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32 minutes ago, Aberdeen Chris said:

Maybe you got some bad fuel and it confused the system, or perhaps like all solid state stuff some of the memory just got corrupted.

I work fixing and rebuilding this kind of digital electronic systems and devices. Often turning it off and unplugging it for a couple of minutes causes the random access memory to discharge and forget the infinite loop of confusion it was caught up in, so allowing when reconnected again for the recalibration and clean refreshed running

I hope your Scooby's happy now 👍

Lets hope so, I did buy some fuel the other week out of necessity from a BP garage whereas I usually use Shell

So disconnecting the Battery for a few minutes in future could resolve the problem, should it occur again.

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Possibly if the system does not have it's own backup Battery like the small button 2032 cell most computers use to keep their bios settings.

But I would want to check with someone who me has done it first, since I don't know if the radio might then need a code to switch on!

I use Shell ultimate every fill, probably not necessary but I did find initially I got more miles from a tank of the posh stuff lol. So I figure it almost pays and the additives help keep the injectors and system clean.

Besides I'm averaging 485 miles a tank of mixed driving so compared to my last Subaru 2.5 pet, it's still miles cheaper

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I use put optimax in every 3rd tank, I get about 500 - 550 miles to a tank on decent runs which is pretty good, there’s something about my XV that the dealers have asked me a couple of times if it’s been chipped because it goes like hot snot (nice litte 90s saying there). It’s much faster than my wife’s newer XV and has a load more torque at bottom end, but no one seems to know why, even Subaru can’t work it out. I had it from new so I know it’s not been tampered with, on optimax it’s really lively.

when they did the relearn on the injectors yesterday it seems to have unleashed even more oomph. Yet it’s still running at around 48mpg on a decent run.

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That's awesome,

You must have run in just right 😈

I believe chipping can release quite a bit more power and use the turbo better to go; but I figure it's possibly not going to give long-term gained unless one changes the exhaust system and cat and DPF to make it worthwhile. 

But I find the wee XV has lots of torque and more than enough power to accelerate oit of a tight spot; once i got the feel of the diesel.

I had a turbo legacy which was fun and sounded awesome at 3000rpm but the power just was not as instant and responsive at the XV.

Maybe I'm getting old but I like to get many miles from my tyres so tend to take it easy on corners, unless it's been snowing in which case it's the ultimate play toy for taking off the traction control and power sliding round tight bends lol. Especially on the alpine 5 snow tyres I'm now running!

Hope your motor is still as happy in a few weeks time 😁

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