I've been experiencing a strange noise on startup and I'm hoping someone can offer some help pinpointing this. It sounds like a scraping metal sound, after I turn the key and it spins over. I'm thinking it is the starter. It doesn't do it every time, but somewhat regularly. Usually after I've driven it a while and not on first startup. The car always starts up just fine, no hesitation or delay ever. It happens with AC on or off. There's no real misbehavior of any kind, other than this noise. Whenever I try and record the sound, it doesn't do it. Go figure. Car has 46k miles on it. Anyone got any insight, and is this something to be concerned with? All help is much appreciated!
Ryan

 

Try to record it, a cellphone with a mic adapter helps but really my first thought is 1 tooth on the starter has gone, my XJ6 did it like scrapey clinging noise on every other start or long starts.

 

AJ16 engine.

Top timing chain tentioner rattle, very common.

There is a heap of info on this in the X300 Tech Section, as its their standard engine.

Simple enough fix.

 

Thanks for the tip Grant. So I read through the X300 section on timing chain tensioner rattles, and I don't believe that's what I've got. It's not a rattle I hear, and it runs smoothly and quietly at idle. It's more of a scraping sound, just right after it turns over and only for a second. My inclination is it's the starter or flywheel I hear. It sounds "dry" or like a metal scraping. And it is infrequent but recurring. Should I just replace the starter? Seems cheap and easy to be sure.

So now you've got me paranoid about the chain tensioners. Am I going to have to replace those sooner or later? Thanks.

 

If it sounds like tin, it could be loose heat shields or flywheel shields. There are heat shields all around the exhaust from the engine to the back wheels. If you can have someone start it, you can try to narrow down what section of the car it's coming from.

 

I agree with Jeff.

Dont throw money at it, the AJ16 is TOUGH.

The only tentioner needing attention, at some stage, and some never, is the top one. That is a distinct RATTLE, enough to really scare you when it strikes. NO damage occurs, just that noise at first fire, cold or hot.

Heat shields, YES. My X300 had a stupid rattle, and a rubber mallet, and tap, tap, tap, all around found the big one on the exhaust manifold the culprit, a quick reshape (bend the sucker) away from the manifold, still silent today.

OK

Starters do go home, but rare.
Flex plates crack, usually a knocking sound.

 

Thanks to all for the help. It's not a heat shield rattle or high pitched tinny buzz. I'm familiar with those. My hunch is the starter/flywheel and I spoke with my mechanic this morning and he agrees that it could be a broken or missing tooth or the solenoid/pinion is not completely disengaging/sticking. I'm translating here so forgive me. I've ordered a reman Bosch starter from RockAuto and hope to get it on in next week or two. I'll get back to the board with updates.

 

remember, it is a 12 point bolt on top of the starter. A 6 point socket will round it off.

 

Could it be that spring that is pulling back starter gear is gone/rusted ? Mine is making grinding sound few moments after start, i am guessing that it is starter.

 

Two things I can think of are harmonic balancer but the car is too new.
The other is the flex plate coming loose.

 

Got my new reman Bosch starter installed today. Mechanic is confident it was the pinion gear sticking. I’ll need to give it some more time to see that the noise is gone for good and will report back soon. Starter cost was $160 with $30 core charge and $125 install cost.

 

I heard the dang scraping noise again today after getting starter replaced yesterday. It happens so infrequently yet recurring that it is really puzzling. I cranked 6 times trying to record it but it didn’t do it. Car runs fine and no unusual sounds when idling etc, just after startup. Air is not on. Ideas anyone? I will keep trying to record it.

 

You'll hear it right after it turns over. There should be two files. Thoughts welcome!

 

30+ for each.

I am still hearing top chain tentioner chatter. Mine was like that, and got worse until I replaced the top tentioner.

Have a read of my Doco I wrote at the time, those tentioners are an issue, even the update units.

Its all to do with the cam lobe profile "back feed" to the top chain. The AJ6 had no issues, as their profile "up" ramp was softer than the AJ16.

 

To my ears I don't hear a chatter coming from the timing chain. It's more external and a metallic buzz sound. The engine idles and runs perfectly quiet and smooth and there is no chatter or other noise coming from timing chain or internally. The sound is not there at any RPM. It is only after initial turn over. In these sound clips it almost sounds like a heat shield but not so much in person. Kind of sounds like a scraping.

 

Could you have a loose fan shroud or perhaps a perished motor mount?

 

I would just like to say you were right on Grant! I should have listened but just couldn't get my head around the fact that it didn't sound like a rattle to me and I couldn't imagine it could be that loud! But it was. My local Jag expert spotted that and installed the newer unit. He agreed that sometimes even those aren't great and can still make noise.. but that he was satisfied mine was the quietest he'd heard and I'm happy with it. Hopefully it stays that way. Well thanks again!