Xk8 still noises after timing chain / tensioners replacement
Thread Starter
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Member
Joined: Dec 2012
Posts: 76
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From: manchester uk
Xk8 still noises after timing chain / tensioners replacement
Hello to all,
Well after a long on and off four weeks without my car I’ve finally completed the task of changing the tensioners and timing chains.
When I removed the chain cover the guides were cracked and chains slack,I though this was bound to be causing the rattling but my heart sank when I fired her up today and the rattle was still there!
Oil pressure is fine,but the rattle seems to come and go with no set pattern,any help would be much appreciated,I’ve tried disconnecting the vvt units but this makes no difference.
Well after a long on and off four weeks without my car I’ve finally completed the task of changing the tensioners and timing chains.
When I removed the chain cover the guides were cracked and chains slack,I though this was bound to be causing the rattling but my heart sank when I fired her up today and the rattle was still there!
Oil pressure is fine,but the rattle seems to come and go with no set pattern,any help would be much appreciated,I’ve tried disconnecting the vvt units but this makes no difference.
Agreed. The AC compressor clutch can rattle, and since the AC cycles on and off based on system needs, it might be your intermittent rattle.
For that matter just turn the AC off and see if that fixes your rattle.
For that matter just turn the AC off and see if that fixes your rattle.
Senior Member
Joined: Jan 2012
Posts: 704
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From: Horten, Norway
Hi.
You have eliminated the chains and tensioners as the sound source. If you have let it run a short time without the serpentine belt and still have the sound, you have eliminated all the auxiliary components as the sound source.
So what is left?
Catalytic converters may rattle when they disintegrate inside. Looking at the fuel trims may give you a hint.
Dropped valve seats or what is left of one dropped, could give you rattle. But this should also give you misfire and a code for such.
A cheap automotive borescope will let you look inside the cylinders through the spark plug holes.
Checking compression may give a clue where the fault is.
Good luck and please report back if you solve the problem.
Oyster
You have eliminated the chains and tensioners as the sound source. If you have let it run a short time without the serpentine belt and still have the sound, you have eliminated all the auxiliary components as the sound source.
So what is left?
Catalytic converters may rattle when they disintegrate inside. Looking at the fuel trims may give you a hint.
Dropped valve seats or what is left of one dropped, could give you rattle. But this should also give you misfire and a code for such.
A cheap automotive borescope will let you look inside the cylinders through the spark plug holes.
Checking compression may give a clue where the fault is.
Good luck and please report back if you solve the problem.
Oyster
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Thread Starter
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Member
Joined: Dec 2012
Posts: 76
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From: manchester uk
Thread Starter
|
Member
Joined: Dec 2012
Posts: 76
Likes: 2
From: manchester uk
Hi.
You have eliminated the chains and tensioners as the sound source. If you have let it run a short time without the serpentine belt and still have the sound, you have eliminated all the auxiliary components as the sound source.
So what is left?
Catalytic converters may rattle when they disintegrate inside. Looking at the fuel trims may give you a hint.
Dropped valve seats or what is left of one dropped, could give you rattle. But this should also give you misfire and a code for such.
A cheap automotive borescope will let you look inside the cylinders through the spark plug holes.
Checking compression may give a clue where the fault is.
Good luck and please report back if you solve the problem.
Oyster
You have eliminated the chains and tensioners as the sound source. If you have let it run a short time without the serpentine belt and still have the sound, you have eliminated all the auxiliary components as the sound source.
So what is left?
Catalytic converters may rattle when they disintegrate inside. Looking at the fuel trims may give you a hint.
Dropped valve seats or what is left of one dropped, could give you rattle. But this should also give you misfire and a code for such.
A cheap automotive borescope will let you look inside the cylinders through the spark plug holes.
Checking compression may give a clue where the fault is.
Good luck and please report back if you solve the problem.
Oyster
Ive tried using a stethoscope but still cannot accurately tell where the noise is coming from.
Thread Starter
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Member
Joined: Dec 2012
Posts: 76
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From: manchester uk
This is strange! I removed the vvt solenoids and they aren’t engaging although there is 12v at the plugs.
I tried the solenoids direct on the battery and they both work fine but they don’t work when plugged into the loom,although there is 12v present! How’s that?
I tried the solenoids direct on the battery and they both work fine but they don’t work when plugged into the loom,although there is 12v present! How’s that?
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Joined: Apr 2014
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From: Jersey, Channel Islands
There will always be +12V on the White/Blue wire at each vvt solenoid connector when the ignition is on.
VVT solenoids are actuated by the ECM grounding the Red/Green & Red/Yellow wires, but not until the engine RPM is (IIRC) around 2000 or so.
I'm afraid that, to my untrained ear, you have an issue with a bottom end bearing. One of the gurus here will doubtless jump in to confirm/refute that.
Sorry, but it doesn't sound good, although I haven't heard what a rattly cat sounds like.
Mike
VVT solenoids are actuated by the ECM grounding the Red/Green & Red/Yellow wires, but not until the engine RPM is (IIRC) around 2000 or so.
I'm afraid that, to my untrained ear, you have an issue with a bottom end bearing. One of the gurus here will doubtless jump in to confirm/refute that.
Sorry, but it doesn't sound good, although I haven't heard what a rattly cat sounds like.
Mike
Last edited by michaelh; Jul 22, 2018 at 08:27 AM.
Veteran Member
Joined: Jul 2015
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From: Sacramento, CA
Do a compression or leak down test. You said that there was slack in the chain. It is possible that the valves hit the top of the piston. The sound you are hearing might be a bent or broken valve. I wouldn't start the car again as all you are doing is causing more damage.
