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SC400 sounds like electric sewing machine!

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Old 09-16-05, 09:30 AM
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p.hase
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Unhappy SC400 sounds like electric sewing machine!

hello CL-pros,

my engine makes a strange noise. a noise like an electric motor whine, like an electric sewing-machine. whenever i accelerate the gas pedal and i rise the RPM i can hear it. its annoying. its much loader inside than my vent/blower or the engine itself.

it sounds exactly like the whirring sound which comes out of your speakers from old radios when you forgot to put a noise suppression choke in front of the DC of your radio. it sucks i can tell you...

i let someone press the gas pedal varying and listened very close to the whole engine - no success. i could only assume its coming of the center of the engine but when i close the hood and sit in the SC its louder inside.

i checked the oil bar of the A/T but could not tell how much was inside. it was 5" more wet than necessary but the oil smells ok. the noise is there in P, N or D position.

its a 1992 SC400 with 103.000 miles. power steering pump and alternator, ATF and differential oil have been changed 10.000miles ago. anyone any idea? engine fan is free in one direction and stiff in the other direction, reservoir is correct. most of the tensioners are ****ed up and squeek and bit and both belts are the first ones. PS: i have an additional louder, whining noise since a while at 45mph.

thanks in advance

george, stuttgart, germany
Old 09-22-05, 01:28 AM
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p.hase
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dealer sprayed many WD40 on the front belt and on the tensioners. The whining noise is still there. its a horrible sound. you could also describe it like the sound you have from the AT when you drive in "R" position. the ATF was 1,5" too full and the dealer said that "they put inside what lexus recommends". i am sceptical. the whining sound is much louder than the engine or exhausts. sad. nobody and idea? please help!
Old 09-23-05, 07:12 AM
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p.hase
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ok. went to the other lexus dealer. he put on his stetoscope. said it must be the timing belt. 105000 miles old and 13 years. maybe he said it has reached his maximum length and the tensioner is strengthening it to the max. now and has reached his end position.

my question is: how can this noise occure from thursday to friday from one second to another??? I still think the noise belongs to the torque converter.

no comment anybody???
Old 09-23-05, 07:33 AM
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mkorsu
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Noises are VERY hard to diagnose. But, if your at 105k miles on the original timing belt, there's a strong chance it's the source of the problem. I would suggest taking the timing belt cover off and checking the belt to see how worn it is. regardless, at 105K I would change it anyway.

Now, if the mechanic said he put in the recommended amount in the trans and the level was too high (not sure what you mean when you say 1.5" too high - do you mean 1.5 qts too high?), but an overfilled trans can and usually will run poorly and possibly even become damaged. I question the ability of that mechanic and wouldn't take the car there again. Drain some of that fluid out, get it to the proper level and see how she drives.
Old 09-23-05, 08:03 AM
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p.hase
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the lexus dealer admitted that they have filled up too high and drained it. the dipstick was 1,5"-2" over HOT position for 9000 miles!!!

the OTHER lexus dealer who said on the phone THIS may have ruinied the torque converter now said it may be caused by the timing belt section after listening to the engine with his stetoscope.

AT jerks a bit from time to time, has the "45mph noise" but the gears change fairly normal. i cannot compare it to my LS430!

how can a timing belt start to sing/whine over night? outside temperature drop from summer to fall? i have seen the timing belt at 94000 and it looked like any other timing belt. no cracks. why should the belt tensioner start to sing that loud?
Old 09-23-05, 08:09 AM
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mkorsu
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Originally Posted by p.hase
the lexus dealer admitted that they have filled up too high and drained it. the dipstick was 1,5"-2" over HOT position for 9000 miles!!!

the OTHER lexus dealer who said on the phone THIS may have ruinied the torque converter now said it may be caused by the timing belt section after listening to the engine with his stetoscope.

AT jerks a bit from time to time, has the "45mph noise" but the gears change fairly normal. i cannot compare it to my LS430!

how can a timing belt start to sing/whine over night? outside temperature drop from summer to fall? i have seen the timing belt at 94000 and it looked like any other timing belt. no cracks. why should the belt tensioner start to sing that loud?
The tensioner itself can go bad and it whines like a banshee. This can be replaced seperate from the belt. Is the whining under the hood very high pitched?
Old 09-23-05, 08:14 AM
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p.hase
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yeah fairly high pitched and very loud! around 1000rpm its does the most noise.

basically it sounds like a car that is "driving in R position" backwards. its similar to that noise.
Old 09-23-05, 08:35 AM
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mkorsu
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Very well could be the bearing in the tensioner is shot. Based on your explanations, this is the direction I'm leaning in. Relatively easy replacement.
Old 09-23-05, 08:57 AM
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p.hase
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maybe the belt grinds somewhere at one of its sides? then the belt would be gone soon. but why should the belt do such things? anyway. i let the dealer who overfilled the AT check the belt in 600 miles when i am there for oil exchange!!!!
Old 09-23-05, 09:04 AM
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Originally Posted by p.hase
maybe the belt grinds somewhere at one of its sides? then the belt would be gone soon. but why should the belt do such things? anyway. i let the dealer who overfilled the AT check the belt in 600 miles when i am there for oil exchange!!!!
If you're referring to the timing belt, it definately should not be grinding at one of the sides! If it is, something is out of position and more than likely throwing the cars timing off. The belt itself only has a life span of roughly 90k miles. Some will fail earlier and some later, but that is Toyota's figure for life span.
Old 09-23-05, 05:14 PM
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Sounds like one of your bearings is about to seize up. That's what happened on my car anyway, it seized, caused too much friction on the serpentine belt and eventually snapped it.
Old 09-28-05, 10:20 PM
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Just a guess, but could it be the bearing in the fan bracket support?? When it seizes it will snap your TB. My personal 1UZ-FE experience confirms this.
Old 09-29-05, 06:19 PM
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Hmm, im having a problem quite similar. The sound you described sounds just like mine. A high picthed squeal/screech at 5k+ rpms. Actually, its exactly at 5k rpms when it starts squealing. Kinda curious to know whats up.
Old 10-05-05, 11:11 AM
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i noticed the interiour light and fan vary in series with the RPMs!!! may it be possible my refurbished OEM alternator is blown after 9 months? how does a bad alternator sound?

as i said in the beginning the sound coming from the engine is exactly like the sound which is coming from your soundsystem if you dont shield it.

SC400 still shifts normal.
Old 10-05-05, 02:45 PM
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na4now
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Slip your serpitine belt off the motor. (its simple....just take a 14mm socket, and a long ratchet.....put it on the bolt in the center of the tensioner pulley.....and push the tensioner down, releaving tension off the belt. Slip the belt off, and menuver it around the fan untill you have it out of the engine bay.)

Crank your car (for a short period of time, just long enough to listen).....If the noise persists, it has to do w/ something behind the timing cover. (i.e timing belt tensioner, ect...) If not, turn the engine off, and spin the accessories by hand. If a bearing is bad, you probably will be able to feel it.

PS Do this at your own risk, or have a mechanic do it if you are not comfortable.

Jordan


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