'00 5s-fe (78k miles) cold start noise around 2,200rpm

[fenixus]

Since a year I can hear a vibrating noise on every cold start of '00 5s-fe engine (now at 78k miles) at around 2,200-2,300rpm (range depends on alt belt tension) whenever cold. it fades away after warm up and is barely noticeable later on. current alternator OEM belt tension is around 120-130lbs.

You Tube

You Tube

I have to add that RPM range of noise appearance changes with the tension of alternator belt (the lower the tension the lower RPM the noise comes in).

Timing belt have been replaced twice together with water pump (they were the reason) in last 20k miles. now running all new OEM seals and gaskets with t-belt and WP (both OEM) and OEM idler since last 10k miles. Tensioner is aftermarket since 20k miles, it wasn't changed to OEM last time (idler was replaced).

Noise was there before last t-belt & WP job and is still there. Any idea what it is ? maybe harmonic balancer (crank pulley) causing it ?

thanks for opinions. I have a hard time pin pointing it.

[71Corolla]

I honestly have no idea, sorry. It sort of sounds like roller bearing rattle, but it's hard to tell from the video, engines don't record well at all, the mic pics up all the wrong frequencies.

[fenixus]

yup, i know that cameras pick wrong things hehe... most normally quiet engines sound like old diesel trucks on camera
it sucks a tad to be honest

anyways that noise you can hear when i rev the engine speed a bit, e.g. at 0:45 secs, 0:56 secs and then after 1:01 (all with camera at different areas)...

it appears to be coming loudest from below alternator, which would lead to water pump (unlikely because this sort of noise was there since like 15k miles) and below it is the crank pulley, that's why i asked about harmonic balancer over there... maybe after the rubber pieces in it get warmer it works better (less vibrating noise?) ? idk ...

JohnGD was telling me that 2,300rpm range is the bearing noise ... but the noise appears NOT to be coming from inside the engine ... rather the belts edge ... don't know ...

anyways engine runs great haha, no error codes, nothing unusual (except for a little vacuum leak somewhere throwing the fuel trims a bit higher into positive values in closed loop).

[TedL]

Is the noise there with the serpentine belt removed?

[fenixus]

Originally Posted by TedL

Is the noise there with the serpentine belt removed?

i haven't tried that yet. I would guess that since noise range moves depending on alt belt tension, then removing belt will affect it.

can remove it and see tomorrow (if nice weather holds).

[TedL]

My thoughts (in no particular order):

Belt itself (pray for this).
Alternator bearings.
A/C clutch bearing ( does A/C on/off affect noise?).

How does belt/pully movement appear? Any wobbles or other motion that's not smooth??

Have you tried a hose stethoscope?

[deadrx7conv]

I had the rattle. Had to replace a working alternator with another perfectly good alternator. Bearing in alternator was bad. AC compressor driven off the same belt too.

Don't rule out something loose. Could be exhaust related, drive train mount related, or something else. Snug everything up and inspect.

Load on the belt is load on the crankshaft pulley is load on the crankshaft and its bearings. Worst case scenario is engine related and/or oil related.

[fenixus]

it's not the belt itself for sure.
alternator belt is 6 months old (OEM Bando) and rattle is still there, was also with old belt).
P/S belt is Goodyear, about 1yr old (rattle was there with old one too).
OEM t-belt is 1yr (13k miles) old and rattle was there with previous (Gates) belt too.

...

the only wobbly pulley is the A/C compressor, but it was always like that since i got the car at 35k miles, no change throughout years.

Switching a/c on or off doesn't affect this kind of rattle (a/c causes its own vibrations, but that's nothing).

Now, since both belts are new and rattle is still there ... I guess only options left are alternator (with its pulley), a/c pulley and crank pulley, correct ?

I will take the alternator belt off tomorrow morning and start the cold engine again (with camera) without this belt to see if rattle is still there at 2,300rpm.
Thing is that with loose alternator belt (like 90-100lbs) the noise range moves down to around 1,800rpm, so i have no idea where it will be without the belt at all.

engine (all 3) mounts and tranny mount are all new (1yr old, all OEM, most of old ones were busted), exhaust sits tight, flex pipe is good (replaced a year ago, was burst open).

... so worst case scenario it's the crankshaft bearing making the noise at cold engine (mostly) and becoming quieter after engine warms up ?

... and best case scenario is either alternator (its pulley actually as alternator works perfectly fine) or one of 2 other pulleys (a/c or crank) makes the noise when cold (mostly) and then becomes quieter ?
... I don't know how about you, but I have a feeling the crank pulley (harmonic balancer) is shot ...

Thanks for suggestions and opinions. I hope tomorrow I will know more.

If rattle goes away completely with no alt belt, then I think it will point to either alternator pulley or a/c pulley being noisy when cold ?
crank will still have the p/s belt attached. I'm not touching it for now, it's a pain in the ass to remove.

I will also try a 3/8'' plastic hose as a stethoscope to pin point the noise source after belt removal (if it's still there).

[AliRazoR]

You Tube

You Tube

[projektvertx]

I'd pick up a mechanic's stethoscope from HFT I think they are like 4-5$ I want to say? Honestly, you don't need anything fancy or accurate for this once, any old stethoscope should do Unfortunately, sound tends to bouce around within the engine bay and you may be misled as to the source of the noise....

[TedL]

Based on what you've said, my money's on the Alt. You can swap the two Alt bearings for $30 +/-. Do brushes while open for another $10.

[fenixus]

thanks for input. be back in an hour or so with more info.

[fenixus]

You Tube

You Tube

ok, here I am.

removed the alternator belt and rattle/noise is still there ... so it's neither the alternator bearing nor the a/c compressor bearing (this is the only wobbly pulley as it's been dented a little LOOONG time ago).

noise range without the alternator belt installed is same as with loose belt, meaning it starts loud around 1,800rpm and continues until after around 2,300rpm. sounds like a perfect fit for a bearing noise

only options left now are under the timing belt cover, crank pulley (harmonic balancer) is still an option ... but using a 3/8'' didn't quite pin pointed it nor the water pump ... so i'm thinking ... maybe it's the tensioner?

The tensioner is an aftermarket one, around 25k miles old / 2yr 9mo old, replaced when original OEM water pump became very noisy at 54k miles in DEC 2007 (all parts used were aftermarket and included crank and cam seals, t-belt, wp and tensioner).

that "new" (back then) Bosch Water Pump started failing (leaking from weep hole) after only 12k miles and 1.5yrs, so I let the same shop re-do the timing/wp job, but that time i gave them my own parts (all OEM including all new seals down to oil pump and new idler no.2 which was not replaced the 1st time, I didn't give them the new OEM tensioner though).

I honestly do not like the idea of removing both belts and opening the timing belt cover to listen to it more closely ... maybe after Winter I will get there, car runs great, for now it's just an annoyance.

any ideas ?

[projektvertx]

I know this is a 1MZ-FE, but here is what my timing belt tensioner bearing sounded like when it got real bad last year. An idler bearing should provoke a similar sound:

[fenixus]

ok thanks. i think your sounded more metal clunking (when camera was getting close to the area) than plastic.

not sure still ... worst case scenario I replace both harmonic balancer and the tensioner for piece of mind. but i think this can wait, the rattle doesn't really get worse over time and it's been like 15k miles so far with it hehe.