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Hello.
Here is the noise I can notice in the following conditions. Both of them have to happen for the noise to show up:
engine cold
put the alternator under load (heater fan at max speed+front+rear defroster)
if the engine is warm this does not happen.
if the engine is cold but alternator is not under load this does not happen as well. When under load, voltage indicator goes from 14V to 13V when car is idle. if I a driving (not idle) the voltage always stays between 13V and 14V
a and on the 14V side.
Here is the video.
Any comment would be useful.
thank you.
The A/C is a seperate belt, so I have eliminated that from the thoughts for now.
That sounds like the early stages of the crank pulley lamination start to give out. The fact its there COLD, and under LOAD is my reason. As the thing heats up the lamination tends to "grip" and no more noise.
The metallic type of sound, if it is metallic, would more than likely be the A/C idler pulley.
Grant, I can't explain how, but have heard a knackered crank damper make an horrendous metallic sound! Motorcarman had one in his shop last year that sounded like a coffee tin half full of pennies in a paint-shaker.
Mine actually got to the point of sounding like a chain skipping rapidly over sprockets before I got round to renewing it. The other two I've experienced, S-Type 3.0L and Excursion 7.3L Dsl, never went beyond a short, high-pitched chirp every 30-45 seconds for about 3 min after cold-start, before they started tossing the belt. My X300 was still functional despite major noise.
I recently replaced the belts on my 95 VDP using Contitech belts.
I still had a noise, sort of metallic, like a bearing. I pulled one belt and felt a little
notchy-ness in the water pump so replaced it. Idler was new Alternator spun free and smooth.
I was stumped.
Found out belt dressing would stop the noise. Weird...not like I was lubricating a bearing with that stuff.
I went and bought a second belt, also a contitech. When the guy brought it out I noticed it was dated. 2.2010. Belt was nearly 8 years old brand new. Hard as a rock.
I asked him to find a newer belt and we found a nice gates that was soft and pliable. Put it on and the noise stopped.
I have never found a belt that made a noise like that...until that one.
Could be a sign of a bearing going bad.
Max stress on altenrator (full load + charging battery after start) combined with cold grease inside the bearings results in noise?
Once warmed up less load on alternator (battery=full) and bearing is fully lubricated/expanded.
But I would first check the crank damper, easy to mark and check.
But I would first check the crank damper, easy to mark and check.
sorry my ignorance, but I do not understand this. What do you mean when you say "mark" the crank damper ? you mean try to inspect it for cracks or something like that ?
in the video I Realize the noise is very metallic, it is exaggerated by the bad mic on the phone I think. But anyway after a few minutes the engine is running, the noise disappears.
It looks really very expensive if it has to be replaced. Price ranges between $500 and $800 just for the replacement parts.
xjfourty:
The crankshaft damper is made up of at least two parts. An inner part that is actually held onto the front of the crankshaft by the big center bolt threaded into the center of the crankshaft snout. The other part is the outer ring that the belts actually ride on. Between the two pieces is a vulcanized piece of rubber that should be bonded to the inner and out parts to hold them together.
Unfortunately what happens over time with exposure to heat, oily fluids and what-not, the vulcanization fails and the two parts then become separated and then these strange noises can occur.
When Dutch-R said to mark and check the damper, he means to crawl under the car or access it on a lift and make marks on the inner and outer parts of the damper to see if over time the marks become misaligned and thus would indicate that the two pieces are no longer properly bonded together.
If you find this is the case, there are places that offer a rebuilding service for the crankshaft damper assembly. I myself have used the damper doctor in the past to rebuild the damper on a 1994 XJ40 car.
Last edited by JensenHealey; Jan 11, 2018 at 12:07 AM.
This is what I was talking about in post #4 above when I suggested you mark your crank damper and report back. Mark it. Start the engine. Go about your daily commute or at least let it run long enough to make the noise, and come up to operating temperature. After shutdown, find your marks and see if they are still aligned. For this bit...you may have to crawl under....or re-start and shutdown until you can find the mark from above.
For future readers....a simple search for the word "Damper" on this forum reveals all this and much, much more. I performed an "advanced search" of this forum for the word "Damper" in threads started by user "Aholbro1" because I knew I'd posted pics that should make it all clear and didn't want to be bothered by the "much, much more" although there's alot of good writings and pics on the damper issue not done by me.
Last edited by aholbro1; Jan 11, 2018 at 07:41 AM.
sorry my ignorance, but I do not understand this. What do you mean when you say "mark" the crank damper ? you mean try to inspect it for cracks or something like that ?
.....
It looks really very expensive if it has to be replaced. Price ranges between $500 and $800 just for the replacement parts.
Take some light paint. Clean the pulley with some brake clean of similar. Paint a line across the side of the pulley.
The pulley has two components separated by rubber. The rubber shears and the components slip.
If the line stays lined up the pulley is not slipping. If the lines become mis aligned they pulley is bad.
there are two different belts running on the crank damper right ?
I think it will be easier for me to mark it from the top rather than underneath the car, so doing it from the hood side at the top.
Anyway I still think the noise here is related to the alternator.
look at this video. When I turn on defroster, heater vent and air conditioner the volt indicator goes down when car is idle (does not happen if the engine is running at any higher rpm). is it normal ?
Anyway sometimes this does not happen I mean there are times when even at idle and under load the voltage sticks on 14V whatever load I put. And when it is so there is no noise
If the pulley has delamination issues, the outer ring (the one that DRIVES the belt/s) is slower than the engine section. The belt is also slower, as is the alternator and water pump, simple.
Age is sadly against ALL the rubber components on these, and any brand car now.
All my Jags have had the pulley revulcanised as an inclusion in my "catch up" at the time of post purchase servicing by me. Even have a spare on the shelf for the S Types when I get around to them.
ok I marked the crank damper. After using the ar 4 days (and with alternator on load) the marks are still aligned. I figured out the noise is coming from the pulley you see in the foreground on this picture.
I had an idler pulley bearing seize, the plastic pulley overheated and disintegrated, and part of the flat rim jammed in the teeth of the timing wheel, smashing a tooth off, so the car was getting two signals per revolution instead of one, to the ECU.
On top of that, the drive belt to the supercharger came off and got chewed in another belt/pulley.
So the car was barely drivable, had about 20bhp, and could hardly limp up the hill home in first gear.
noise from serpentine/pulleys
