Xj6 engine noise please help

Any decent FLAPS should have the alternator, or see if you can find a car in a junkyard.

The alternator is fine I believe just the pulley that connects it to the crank is all loose. The alternator spins freely and wasn’t causing any issues that I know of. I think now I need advice/tips on fixing that pulley before anything else. Any help would be greatly appreciated. https://youtu.be/RMzIpdoiJHA

in that last vid, it looks like it is the Water pump pulley is wobbly?? = bad water pump

what exact pulley is wobbling ?

I think the Alt pulley is an interference press fit on the shaft (I could be wrong)

You do not want to be driving it if something lets go in the front

Hey tony, so the pulley that I think is the cause of my noise is the one the connects the alternator to the crank I just updated the link on the previous post. I haven’t been driving the car since I thought that was internal noise until I found that today. Won’t be driving it like that… so one of my posts got flagged by the community. Sorry I’m still new to the forums and learning the format

Be careful: if the pulley was loose, there’s a good chance the rotor shaft is damaged.

I viewed your update vid…

I am unfamaliar with the S3 layout, but that looks a bit like a loose bracket
(its still not 100% clear to me on yr new vid)

Is that an idler pulley bracket bolts worked loosed from the block ?

Does the pulley that is on the alternator wobble ?

all fairly easily fixable anyway :slightly_smiling_face:

It is a little difficult to see exactly what you are showing that is loose in your last updated video but it appears to me that your Crankshaft Damper (EAC4050) has failed.
The attached picture shows an engine similar to yours that I built up engine right before I installed it in my 1984 XJ6 Vanden Plas. The Crankshaft Damper identified in the picture with an arrow. Is this the part that has failed in your car?


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Ok so feeling the alternator side it seems not have any give. And yes that is the correct part that you pointed out in the pic. Crankshaft damper. So from what I see that pulley has 3 belts on it 1st one is for water pump fan and ps pump 2nd runs the ac compressor and 3rd running the alternator. The 3rd one is the loose one. https://youtu.be/_d7UU3uosWA Here’s the video I just made. It shows pretty clear what I’m seeing considering we now know what part it is

It appears to me there is no belt running within a groove, and it is innermost to the engine ?

In that case, your crankshaft damper outer has probably separated form its inner due to failure of the rubber bond

(it still is a bit hard to be sure from the vid)

To check, insert a mirror, and inspect, it will be obvious…there are timing marks on the pulley, they should not move, except with the engine

you are close to resolution, a new damper can be done by the home mechanic

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You are correct about the three belts and how they are driven by the Crankshaft Damper (also sometimes referred to as the Harmonic Balancer). The fourth belt is for the Air Pump but that is driven by the water pump pulley and not directly by the Crankshaft Damper.

The Crankshaft Damper is made by bonding metal pulleys together with a rubber like material. If the rubber has failed and the pulleys have separated then you will need a replacement Crankshaft Damper or you could send yours out to be rebuilt. Rebuilding a Crankshaft Damper is not a Do-It-Yourself job in my opinion however I don’t doubt that someone has done it. :wink: However removing and replacing the Crankshaft Damper can be a Do-It-Yourself job if you have the tools, place to work, and the patience. BTW since you will have to remove at least three of the belts to remove and replace the Crankshaft Damper there is no better time to replace them with new ones especially if you have no idea when they were last replaced .


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All the belts are still in there place. Yes it’s the innermost one that’s moving. So it does seem that the damper has came apart. How would I go about replacing that part

S3 owners can advise whether it is possible with the radiator in place.

remove the belts and outer pulleys
unscrew the 1-5/16" bolt
remove the damper with a tool

As a general rule, (on other vehicles) the job is easier with the radiator and grille out,
but quicker if you dont need to

It is advisable to own a copy of the Factory Service and Parts manuals

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I have a couple of good used spare, free for the postage.

Oh that’d be convenient. How much for the part? I’m in Dallas Texas Also I appreciate all the help really didn’t expect this. If anyone has more tips and tricks on replacing the pulley I’d be putting them to good use. :slight_smile: Maybe there’s a thread on replacing the crankshaft damper/ harmonic balancer one of you could refer me to?

search the archives…maybe not too many people have swapped a S3 HB in situ though.
I have not

The S2 FSM says to knock it off with a mallet…lol

I would suggest rent or buy ($20) a “Harmonic Balancer puller kit”

but you usually need ~min 4-5" clearance direct in front of damper bolt for it to be able to work

If for some reason, this cannot be achieved, I guess you could try to knock the inner cone off, but they are on pretty tight. A combo of puller 1st, then mallet means less clearance is needed

a tip is to use a washer or nut to avoid the tapered puller bolt potentially damaging the leading female thread of the crankshaft

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Thanks for the tip. I was thinking maybe I’ll have enough space by removing the fan and the shroud. I just watched a HB replacement video on a xj40 and that’s how he did it

As Paul says, Jabraan - the outer and inner part of the pulley are bonded together by rubber…

…so do check that the inner part is still firmly fixed, and the wobble is due to failed rubber. In which case the swap only requires the damper itself - the main problem is likely to remove the bolt holding things together.

Also carefully save the tiny Woodruff keys which tends to fall out as the pulleys are removed. And do inspect them and their grooves to ensure a firm reassembly…:slight_smile:

xj6 85 Sov Europe (UK/NZ)


So from what I understand the crankshaft damper has 3 pulley. The forward 2 are tight the inner most one that’s connected to the alternator seems to be moving around freely. I suppose the alternator isn’t charging either because of how bad the pulley is. All 3 of these are supposed to be fused together or am I missing something? Edit. I suppose if someone has a picture of the crank shaft damper I could better see what’s broken on mine. I couldn’t really find a pic online

Perhaps these pictures of the Crankshaft Damper from the failing engine that I recently removed from my 1984 XJ6 Vanden Plas will help.
You are basically correct but I would say “bonded together with rubber” rather than “fused”.
Your Crankshaft Damper failure is somewhat unusual for the 4.2L XK engine. It is the first that I recall hearing about in my almost 20 years on Jag-Lovers. The failure seems more common on the 5.3L V12 and I had to remove and replace the one on my wife’s 1990 XJ-S convertible several years ago.


Thanks Paul that picture certainly does the trick. Looking at the timing marks since mine moves around on its own they probably are all out of alignment. This is where it’s broken from