[ippyiain]

Hi
Over the last couple of months I've noticed a noise when starting. Best way to describe it is a sort of metallic "zing". It starts just as the engine catches and lasts for 1-2 seconds max.

Once the noise is gone it doesn't reappear on any startup or while running until the car has been left standing... it only happens when the car is absolutely cold - i.e. after at least 8-10 hours without running.

I thought it might be a starter motor issues but it's definitely coming from the r/h side not the trans side of the block.

Took the serpentine belt off and checked all the pulleys - nothing obvious.

This morning I changed the oil and when I started it back up the noise was there again... slightly quieter but still distinct... and I now think it is coming from the cam cover.

As the oil had been left to drain completely could this possibly be a dodgy cam follower?

The engine has done 120k miles but has always had fully synth 5w/40 and Wynns engine flush used on every change at 5-6k since i bought it at 25k. Lifted the cover off last year and it was very clean inside and the oil always comes out good without crud in it ( although I've not dropped the sump yet)

Any suggestions how I can confirm whether this is the case?

Thanks in advance!

 

[BobSaabit]

Just to confirm location, remove the serp from the idler/tension pulleys so it's very loose and start it cold. See if the noise is there. That should eliminate the accessories from suspicion. A bearing going dry would act the same as what you are hearing but might not have enough play for the wiggle test to detect it.

If it's still there then you can be more confident of a motor or turbo noise. Next step would be to have a friend start it while you listen with a stethoscope, but it will be a PITA to find if it goes away in a couple seconds and requires hours to retest.

 

[ippyiain]

Thanks Bob... I didn't start it up with the belt off but will give that a go next.

Cheers

 

[Pontius DIO]

Have a feeling this is the same thing mine is doing. Only when cold, only during initial cranking, and a zinging sound- non of which reappear until the car has been sitting for awhile. I'm still thinking it's the starter though- like it's transmitting the noise through the flywheel or possibly the solenoid is NOT engaging 100% and maybe the gear from the starter isn't seating correctly on the flywheel's teeth. Sound like your noise?

I've been waiting for a warm day (been in the 30's for awhile) to see if the sound persists or not, as the noise started to get my attention about a week ago. Was also thinking the starter was getting tired and working harder to turn over the engine's cold 10W 30 synthetic which is due for a change. Please update if you get a definite fix as I'd like to try it, and I'll update if I figure anything out.


EDIT: I don't think it's turbo related as the engine is only cranking and not pumping enough air to get the turbo going. Also, I'd have to think the turbo would keep making the noise if it were the case. My sound also sounds like it's coming from the P/S firewall area, but I haven't been out of the car to pinpoint the noise.

Maybe the alternator bearings are dry? Spinning an alternator by hand won't work as it needs current to "turn on". Try starting the car with the belt off the alternator and then spin it....see a difference? I'm assuming the alternator has an instant on wire as opposed to being at a certain RPM. Haven't messed with these yet, so still not sure.

 

[ippyiain]

Pontius... I originally thought starter but the noise for mine seems to be around the pulleys/cam box area... although may be a trick of the sound! I also thought if it was starter it would more likely happen every/most starts whereas mine def only happens when the motor is stone cold and been standing for 8 hours or more.

Sounds like it's going to be one of those frustrating and irritating games of hunt the fault!!

Sure - will let you know if I find it... or when I go mad... whichever comes first!

 

[BobSaabit]

A mechanic's stethoscope can be a real assist in finding bad bearings. Sometimes (even if some initial noise is gone) you can still hear the bearing making odd but low noises if you get the stethoscope right up next to the bearing on the housing. Use caution with rotating belts.

 

[Pontius DIO]

A mechanic's stethoscope can be a real assist in finding bad bearings. Sometimes (even if some initial noise is gone) you can still hear the bearing making odd but low noises if you get the stethoscope right up next to the bearing on the housing. Use caution with rotating belts.

Another way to describe the sound is like a weird, subdued cough that only lasts during cranking (cranks about 1-2 sec then fires up) and stops as soon as the starter disengages. Can't believe this issue is an "unknown" for the gurus when we both have it at the same time LOL. Guess we get to be pioneers with solving this oddity- just hope it's a simple fix (replacing a head isn't a simple fix tho :roll

This is one of those reasons why I absolutely HATE the ACC turning the heater on with the car as it puts an instant load on the alternator before the car is running, and I can't get the manual over-ride to keep after 10 min.

 

[BobSaabit]

Not sure if you know this, but you can reprogram the car to start with the heating/cooling system in the OFF position.

 

[Pontius DIO]

I've tried what the manual says, it'll beep giving a confirmation, then 10 min after sitting reverts back. I dunno why they couldn't just make a sub-menu with on/off, temp on/off, etc. Extremely annoying.

 

[First9-3]

Just to confirm location, remove the serp from the idler/tension pulleys so it's very loose and start it cold. See if the noise is there. That should eliminate the accessories from suspicion. A bearing going dry would act the same as what you are hearing but might not have enough play for the wiggle test to detect it. .

+1 on this idea.

May as well repack the idler pulley bearing with grease while the belt is loose. VERY easy to do.

 

[ippyiain]

Started up with the belt off and no noise... also greased the idler pulley as suggested.

Noise is still there on totally cold startups and convinced it is coming from the cam box.

I changed the plugs yesterday and noticed cyl 1 seems to be running leaner than the others... see http://flic.kr/p/bozK43.

Plug from cyl 1 on left - the other 3 were the same as the one on the right.

Could this be the result of a follower that is failing? (Not that I'm stuck on that as an idea !!)

 

[BobSaabit]

Started up with the belt off and no noise... also greased the idler pulley as suggested.

Just verifying that this is not a typo... of there was no noise with the belt off, then it's an external problem.

 

[ippyiain]

I knew what I meant... but my fingers didn't !! The noise was there on startup but there was no noise from the pulleys when I checked them!

 

[BobSaabit]

I knew what I meant... but my fingers didn't !! The noise was there on startup but there was no noise from the pulleys when I checked them!

OK... then it's definitely internal.

 

[euroteck2]

considerring the fact that youve allready ruled out belt driven accessories. your on the right track..if this car was at my shop i would go out to the car pull the valve cover and see if any valves have excessive lifter clearence. youll pull the valve cover and make a chart to keep track of what valves and what holes have been done(its hard to remeber with so many valves) the cam lobe should be pointing up directly opposite of the lifter(or follower as you call them) use some thing solid but not sharp. if that lifter can be pushed down after not operating for however long then that lifter is bleeding down. since you think the #1 hole is running lean if any of the intake lifters on that hole are bad they wont open the intake valve enough to reach full compression. resulting in a lean cylinder. just a couple of thoughts

 

[ippyiain]

euroteck2... thanks for this... the tip about checking by pushing down while everything still in place is handy because I was prepared to remove the cams and check the followers out of the head.

Time to order a valve cover gasket and start checking !