New Noise Under Hood

[prix]

After running errands, I pulled over to park, thought I heard something under the hood, so got out to listen. There's definitely a noise. It sounds like something needs to be oiled, or is loose and rattle-y. It's a low somewhat rhythmic sound. Almost like something is turning but not lubricated? Almost a rhythmic grinding noise? It's hard to describe. The fan belt was replaced about 1.5 years ago (and I didn't see any cracks or splits when I looked at it earlier today), and I also had the timing belt replaced about 2 years ago. The radiator is not more than three years old. The entire power steering system was replaced about four years ago.

The only mechanical issue I know I have are torn bushings in the front strut mount.

What can this be? I let the car sit a few hours and just went out again and started it up. The noise seems a little louder than before (or maybe there is less traffic so it is easier to hear).

It's never a good time to have a car repair, but this is the worst of all possible times. I am ill with worry. I have about a mile drive to get to a gas station (they have a repair bay there) where someone could look at it.

Any ideas appreciated. If you need more detail, I will do my best. I have listened twice now and can't locate the specifics of where the noise is coming from. Under the hood is a little vague, I know. My best guess is that it's more toward the front than the back.

[prix]

I just searched the forums and saw another post about a noise caused by a bad idler belt pulley. What kind of sound would it make if this were an idler belt pulley? Would it be high pitched or low? Whatever I am hearing sounds like something is going out, or getting ready to fly off. I was almost afraid to put my head to far under the hood! Ack! I have ALL fingers crossed that this is going to be an inexpensive repair. Fat chance. I better sign off now before I lose my mind.

[prix]

Meant to say SERPENTINE belt was replaced a few years ago, not FAN belt.

After running errands, I pulled over to park, thought I heard something under the hood, so got out to listen. There's definitely a noise. It sounds like something needs to be oiled, or is loose and rattle-y. It's a low somewhat rhythmic sound. Almost like something is turning but not lubricated? Almost a rhythmic grinding noise? It's hard to describe. The fan belt was replaced about 1.5 years ago (and I didn't see any cracks or splits when I looked at it earlier today), and I also had the timing belt replaced about 2 years ago. The radiator is not more than three years old. The entire power steering system was replaced about four years ago.

The only mechanical issue I know I have are torn bushings in the front strut mount.

What can this be? I let the car sit a few hours and just went out again and started it up. The noise seems a little louder than before (or maybe there is less traffic so it is easier to hear).

It's never a good time to have a car repair, but this is the worst of all possible times. I am ill with worry. I have about a mile drive to get to a gas station (they have a repair bay there) where someone could look at it.

Any ideas appreciated. If you need more detail, I will do my best. I have listened twice now and can't locate the specifics of where the noise is coming from. Under the hood is a little vague, I know. My best guess is that it's more toward the front than the back.

[landar]

First off, don't panic... and look for something simple. Are you mechanically inclined?

There are a couple of "simple" things that I would try. First is listening as you have done. However, with noises it is often very difficult to determine the source as they play tricks on your ears.

Next, I would take a can of WD40 and give a quick spritz (thats technical jargon for "dont over-do it") on the serpentine belt. Noisy contact with pulleys will often quiet down. Finally, I would just pull the serp belt off and run the engine for a brief period. No driving, just idling in the driveway. It should run w/o the belt although the alt. light will be on. If any of those help, you can go from there.

Only 66k on a 94? Nice.

[prix]

Thanks. No, not mechanically inclined. I'll try the WD40 and see if that has any effect. So if it makes no noise when the belt is off what does that prove?

First off, don't panic... and look for something simple. Are you mechanically inclined?

There are a couple of "simple" things that I would try. First is listening as you have done. However, with noises it is often very difficult to determine the source as they play tricks on your ears.

Next, I would take a can of WD40 and give a quick spritz (thats technical jargon for "dont over-do it") on the serpentine belt. Noisy contact with pulleys will often quiet down. Finally, I would just pull the serp belt off and run the engine for a brief period. No driving, just idling in the driveway. It should run w/o the belt although the alt. light will be on. If any of those help, you can go from there.

Only 66k on a 94? Nice.

[landar]

So if it makes no noise when the belt is off what does that prove?

It proves that the noise is in the accessory drive train. It could be belt, idler pulley, tensioner, PS pump, alt, AC compressor, fan bracket, etc.

IF the noise does not go away w/o the belt, you have other issues. But I am fairly confident that it is in the accessory area. If the WD helps then it might even be the belt (or maybe tensioner).

Then I would put the belt back on and use a mechanics stethoscope to isolate the noise. You could just do that now but be VERY careful around moving parts.

If not mechanically inclined, find a shop and have them troubleshoot.

[prix]

Ok, that narrows it down. :-).

One more question: If this is an accessory drive train issue, is it necessary to take it to a 'Lexus' shop? I ask, as to get to the shop I usually use will require a long tow (covered by my insurance), whereas a gas station with some old timer mechanics is about a mile away (they successfully replaced an alternator for me several years ago).

Thanks for all your input.

So if it makes no noise when the belt is off what does that prove?

It proves that the noise is in the accessory drive train. It could be belt, idler pulley, tensioner, PS pump, alt, AC compressor, fan bracket, etc.

IF the noise does not go away w/o the belt, you have other issues. But I am fairly confident that it is in the accessory area. If the WD helps then it might even be the belt (or maybe tensioner).

Then I would put the belt back on and use a mechanics stethoscope to isolate the noise. You could just do that now but be VERY careful around moving parts.

If not mechanically inclined, find a shop and have them troubleshoot.

[prix]

Here is my thinking on all the parts you mentioned:

1) BELT - Just by eyeballing it, the serpentine belt looks fine, and it's also relatively new. I did see a slight wriggle when watching it on idle yesterday. I thought I saw a slight 'hitch' as it circled (off to one side off and on), but have no idea whether that is normal 'play' (?);

2) IDLER PULLEY - From what I have read, the idler pulley would make a different noise, more of a screeching noise;

3) POWER STEERING PUMP - The pump and all related power steering components were replaced maybe five years ago. The power steering fluid was checked (and was normal) about a month ago.

4) ALTERNATOR - It's a 4 y/o rebuilt that tested in the 'normal output' range a few months ago, though was a little on the weak side (not by much). The guy from AAA who ran the tests on my dead battery said not to run the A/C and the radio at the same time, because over time that could wear down the battery again. We never did figure out why the battery was completely drained one day.

5) A/C COMPRESSOR - I have no knowledge of this part or even where it is. It sounds expensive.

6) FAN BRACKET - Someone else described a noise similar to what I am hearing (I think it was a Club Lexus post) and this was the culprit. They replaced a bunch of other bearings and such while they were 'in there'.

[davispb]

Here is my thinking on all the parts you mentioned:

1) BELT - Just by eyeballing it, the serpentine belt looks fine, and it's also relatively new. I did see a slight wriggle when watching it on idle yesterday. I thought I saw a slight 'hitch' as it circled (off to one side off and on), but have no idea whether that is normal 'play' (?);

2) IDLER PULLEY - From what I have read, the idler pulley would make a different noise, more of a screeching noise;

3) POWER STEERING PUMP - The pump and all related power steering components were replaced maybe five years ago. The power steering fluid was checked (and was normal) about a month ago.

4) ALTERNATOR - It's a 4 y/o rebuilt that tested in the 'normal output' range a few months ago, though was a little on the weak side (not by much). The guy from AAA who ran the tests on my dead battery said not to run the A/C and the radio at the same time, because over time that could wear down the battery again. We never did figure out why the battery was completely drained one day.

5) A/C COMPRESSOR - I have no knowledge of this part or even where it is. It sounds expensive.

6) FAN BRACKET - Someone else described a noise similar to what I am hearing (I think it was a Club Lexus post) and this was the culprit. They replaced a bunch of other bearings and such while they were 'in there'.

I recently had the bearings go out on the fan bracket in my '92. I could hear and feel the vibration when the car was at idle. Opened the hood and could see an intermittent "slow" of the fan when car was idling. I took the drive belt off and spun the fan. Instead of coming to a gradual halt, the fan would slow abruptly, so, bingo!, bearings in the fan bearing bracket were junk. Car was also at 258k mi., with the last tb/wp at 119k, so I went ahead and did it all. Car runs like new, just have to replace windscreen and figure a fix for old, cracked seats. I told you all of that to tell you this: my suspicion is that your problem is worn bearings in the fan bearing bracket. Best of luck!

[prix]

I see, that's great that you were able to figure it out that way. I have zero mechanical skills (or tools) so even trying that is above my pay grade (removing the belt).

Can you be more specific about the noise you heard? I would not describe what I am hearing as 'vibration'. This is low rough rumbling noise with what sounds like grinding noise thrown in the mix. Does that ring a bell? It does sound like something could fly off any minute. But yes, from all the info I've read it does sound like a fan bearing is the likely culprit.

Here is my thinking on all the parts you mentioned:

1) BELT - Just by eyeballing it, the serpentine belt looks fine, and it's also relatively new. I did see a slight wriggle when watching it on idle yesterday. I thought I saw a slight 'hitch' as it circled (off to one side off and on), but have no idea whether that is normal 'play' (?);

2) IDLER PULLEY - From what I have read, the idler pulley would make a different noise, more of a screeching noise;

3) POWER STEERING PUMP - The pump and all related power steering components were replaced maybe five years ago. The power steering fluid was checked (and was normal) about a month ago.

4) ALTERNATOR - It's a 4 y/o rebuilt that tested in the 'normal output' range a few months ago, though was a little on the weak side (not by much). The guy from AAA who ran the tests on my dead battery said not to run the A/C and the radio at the same time, because over time that could wear down the battery again. We never did figure out why the battery was completely drained one day.

5) A/C COMPRESSOR - I have no knowledge of this part or even where it is. It sounds expensive.

6) FAN BRACKET - Someone else described a noise similar to what I am hearing (I think it was a Club Lexus post) and this was the culprit. They replaced a bunch of other bearings and such while they were 'in there'.

I recently had the bearings go out on the fan bracket in my '92. I could hear and feel the vibration when the car was at idle. Opened the hood and could see an intermittent "slow" of the fan when car was idling. I took the drive belt off and spun the fan. Instead of coming to a gradual halt, the fan would slow abruptly, so, bingo!, bearings in the fan bearing bracket were junk. Car was also at 258k mi., with the last tb/wp at 119k, so I went ahead and did it all. Car runs like new, just have to replace windscreen and figure a fix for old, cracked seats. I told you all of that to tell you this: my suspicion is that your problem is worn bearings in the fan bearing bracket. Best of luck!

[prix]

Update: Sprayed the serpentine belt with a little water this morning and also checked the fan blades for nicks. The blades looked clean. I also pulled/pushed on the fan (as much as possible, it's hard to get to) but could not detect any 'play'. The fan that I am looking at is in behind the radiator and in front of the serpentine belt.

I cranked it up and there was less rumbling and grinding than yesterday, but I think that's only because it had not had time to get warmed up! I heard more of a rhythmic loose bouncy noise (though definitely still some faint rumbling as well).

Looking at the fan from top down, there is a big round thing (maybe 4" diameter) that the fan is attached to, and that is where the noise seems to be coming from. The round part seemed to have a bit of a wobble. Is that the fan bracket assembly/bearing? If not, what is that part called? Thanks.

[landar]

That is your fan clutch which is bolted to the fan bracket with the pulley bearing that is suspect.

Does your info say that your LS has only 66k miles? Oh, see now it is 93k. Would not think the fan bracket would go bad at that mileage but it is entirely possible.

With the engine off, just grab the fan clutch assembly and see if you can wiggle it. Should not budge. If it does, the fan bracket bearing is shot.

The old timers up the street should be able to change it for you.

[prix]

Thanks for following up on this. I will check that out for wiggle...though I could NOT get it to budge this morning...I'll try one more time (and maybe push/pull harder). Assuming it doesn't budge, and that it's the fan clutch/pulley, any idea how much labor needed to fix that? Ballpark? Based on some past experiences, I've learned that it pays to have an idea of what is reasonable going in.

Btw, hadn't updated that profile since registering here in 2004 (actually did not know I could update it). So in 6 years I've put on a little less than 30K miles. Even at 93K it's still very low mileage for a 1994! Thanks again.

That is your fan clutch which is bolted to the fan bracket with the pulley bearing that is suspect.

Does your info say that your LS has only 66k miles? Oh, see now it is 93k. Would not think the fan bracket would go bad at that mileage but it is entirely possible.

With the engine off, just grab the fan clutch assembly and see if you can wiggle it. Should not budge. If it does, the fan bracket bearing is shot.

The old timers up the street should be able to change it for you.

[prix]

Sorry, I think I misinterpreted your post. In rereading it, what I think you are saying is that the pulley is part of the fan bracket assembly, not part of the fan clutch.

That is your fan clutch which is bolted to the fan bracket with the pulley bearing that is suspect.

Does your info say that your LS has only 66k miles? Oh, see now it is 93k. Would not think the fan bracket would go bad at that mileage but it is entirely possible.

With the engine off, just grab the fan clutch assembly and see if you can wiggle it. Should not budge. If it does, the fan bracket bearing is shot.

The old timers up the street should be able to change it for you.

[davispb]

Here is my thinking on all the parts you mentioned:

1) BELT - Just by eyeballing it, the serpentine belt looks fine, and it's also relatively new. I did see a slight wriggle when watching it on idle yesterday. I thought I saw a slight 'hitch' as it circled (off to one side off and on), but have no idea whether that is normal 'play' (?);

2) IDLER PULLEY - From what I have read, the idler pulley would make a different noise, more of a screeching noise;

3) POWER STEERING PUMP - The pump and all related power steering components were replaced maybe five years ago. The power steering fluid was checked (and was normal) about a month ago.

4) ALTERNATOR - It's a 4 y/o rebuilt that tested in the 'normal output' range a few months ago, though was a little on the weak side (not by much). The guy from AAA who ran the tests on my dead battery said not to run the A/C and the radio at the same time, because over time that could wear down the battery again. We never did figure out why the battery was completely drained one day.

5) A/C COMPRESSOR - I have no knowledge of this part or even where it is. It sounds expensive.

6) FAN BRACKET - Someone else described a noise similar to what I am hearing (I think it was a Club Lexus post) and this was the culprit. They replaced a bunch of other bearings and such while they were 'in there'.

I recently had the bearings go out on the fan bracket in my '92. I could hear and feel the vibration when the car was at idle. Opened the hood and could see an intermittent "slow" of the fan when car was idling. I took the drive belt off and spun the fan. Instead of coming to a gradual halt, the fan would slow abruptly, so, bingo!, bearings in the fan bearing bracket were junk. Car was also at 258k mi., with the last tb/wp at 119k, so I went ahead and did it all. Car runs like new, just have to replace windscreen and figure a fix for old, cracked seats. I told you all of that to tell you this: my suspicion is that your problem is worn bearings in the fan bearing bracket. Best of luck!

In my case, the noise was a lower tone than the engine at idle. It was intermittent, with associated vibration. That is to say: the engine would hum along as per usual at idle and then the engine would feel and sound as if it were "bogging down," as if something were applying an undue load to the engine. If I sat in the driver's seat and placed my right hand on the middle of the dash above the seats, I could feel a noticeable vibration during the "bogging down." What was happening was that the bearings on the fan clutch bracket were so worn, the fan was unable to turn freely and smoothly-trying to stop turning, even. That, in turn, was placing more load on the drive (serpentine) belt trying to turn the mechanical fan and causing the engine to work harder to rotate everything, thus the "bogging down." It was not constant , but came and went (department of redundancy dept.?). When I removed the drive belt from the fan pulley, I was unable to appreciate any undue "play" or "wiggle" in the fan, but the fan would not rotate freely. How can I put this? It was like there was a tangle on the middle of a yo-yo string, such that the yo-yo doesn't unwind smoothly. Also, when I applied a decent amount of throttle between 35-45mph, there was a noise and vibration like when you thumb-shuffle two halves of a deck of cards together. Sorry for the length, but that is the best way I can explain. I hope this helps in some way.

[prix]

Thanks. Yes, it was the fan bracket bearing. The idler bearing was on its way out, so that was replaced too. Here's the rub. The mechanic who worked on the car told me that the shop that last replaced the serpentine belt put on The Wrong Size, as in 'too small'. The mechanic said it was on there so tight they had a really hard time getting it off. You know, if I take my car in to a shop, and if I ask for a simple thing to be done, like replace that cracked serpentine belt, I should not have to second guess that person's work. Right? I mean, HOW HARD CAN IT BE?

Here is my thinking on all the parts you mentioned:

1) BELT - Just by eyeballing it, the serpentine belt looks fine, and it's also relatively new. I did see a slight wriggle when watching it on idle yesterday. I thought I saw a slight 'hitch' as it circled (off to one side off and on), but have no idea whether that is normal 'play' (?);

2) IDLER PULLEY - From what I have read, the idler pulley would make a different noise, more of a screeching noise;

3) POWER STEERING PUMP - The pump and all related power steering components were replaced maybe five years ago. The power steering fluid was checked (and was normal) about a month ago.

4) ALTERNATOR - It's a 4 y/o rebuilt that tested in the 'normal output' range a few months ago, though was a little on the weak side (not by much). The guy from AAA who ran the tests on my dead battery said not to run the A/C and the radio at the same time, because over time that could wear down the battery again. We never did figure out why the battery was completely drained one day.

5) A/C COMPRESSOR - I have no knowledge of this part or even where it is. It sounds expensive.

6) FAN BRACKET - Someone else described a noise similar to what I am hearing (I think it was a Club Lexus post) and this was the culprit. They replaced a bunch of other bearings and such while they were 'in there'.

I recently had the bearings go out on the fan bracket in my '92. I could hear and feel the vibration when the car was at idle. Opened the hood and could see an intermittent "slow" of the fan when car was idling. I took the drive belt off and spun the fan. Instead of coming to a gradual halt, the fan would slow abruptly, so, bingo!, bearings in the fan bearing bracket were junk. Car was also at 258k mi., with the last tb/wp at 119k, so I went ahead and did it all. Car runs like new, just have to replace windscreen and figure a fix for old, cracked seats. I told you all of that to tell you this: my suspicion is that your problem is worn bearings in the fan bearing bracket. Best of luck!

In my case, the noise was a lower tone than the engine at idle. It was intermittent, with associated vibration. That is to say: the engine would hum along as per usual at idle and then the engine would feel and sound as if it were "bogging down," as if something were applying an undue load to the engine. If I sat in the driver's seat and placed my right hand on the middle of the dash above the seats, I could feel a noticeable vibration during the "bogging down." What was happening was that the bearings on the fan clutch bracket were so worn, the fan was unable to turn freely and smoothly-trying to stop turning, even. That, in turn, was placing more load on the drive (serpentine) belt trying to turn the mechanical fan and causing the engine to work harder to rotate everything, thus the "bogging down." It was not constant , but came and went (department of redundancy dept.?). When I removed the drive belt from the fan pulley, I was unable to appreciate any undue "play" or "wiggle" in the fan, but the fan would not rotate freely. How can I put this? It was like there was a tangle on the middle of a yo-yo string, such that the yo-yo doesn't unwind smoothly. Also, when I applied a decent amount of throttle between 35-45mph, there was a noise and vibration like when you thumb-shuffle two halves of a deck of cards together. Sorry for the length, but that is the best way I can explain. I hope this helps in some way.

[davispb]

Thanks. Yes, it was the fan bracket bearing. The idler bearing was on its way out, so that was replaced too. Here's the rub. The mechanic who worked on the car told me that the shop that last replaced the serpentine belt put on The Wrong Size, as in 'too small'. The mechanic said it was on there so tight they had a really hard time getting it off. You know, if I take my car in to a shop, and if I ask for a simple thing to be done, like replace that cracked serpentine belt, I should not have to second guess that person's work. Right? I mean, HOW HARD CAN IT BE?

Here is my thinking on all the parts you mentioned:

1) BELT - Just by eyeballing it, the serpentine belt looks fine, and it's also relatively new. I did see a slight wriggle when watching it on idle yesterday. I thought I saw a slight 'hitch' as it circled (off to one side off and on), but have no idea whether that is normal 'play' (?);

2) IDLER PULLEY - From what I have read, the idler pulley would make a different noise, more of a screeching noise;

3) POWER STEERING PUMP - The pump and all related power steering components were replaced maybe five years ago. The power steering fluid was checked (and was normal) about a month ago.

4) ALTERNATOR - It's a 4 y/o rebuilt that tested in the 'normal output' range a few months ago, though was a little on the weak side (not by much). The guy from AAA who ran the tests on my dead battery said not to run the A/C and the radio at the same time, because over time that could wear down the battery again. We never did figure out why the battery was completely drained one day.

5) A/C COMPRESSOR - I have no knowledge of this part or even where it is. It sounds expensive.

6) FAN BRACKET - Someone else described a noise similar to what I am hearing (I think it was a Club Lexus post) and this was the culprit. They replaced a bunch of other bearings and such while they were 'in there'.

I recently had the bearings go out on the fan bracket in my '92. I could hear and feel the vibration when the car was at idle. Opened the hood and could see an intermittent "slow" of the fan when car was idling. I took the drive belt off and spun the fan. Instead of coming to a gradual halt, the fan would slow abruptly, so, bingo!, bearings in the fan bearing bracket were junk. Car was also at 258k mi., with the last tb/wp at 119k, so I went ahead and did it all. Car runs like new, just have to replace windscreen and figure a fix for old, cracked seats. I told you all of that to tell you this: my suspicion is that your problem is worn bearings in the fan bearing bracket. Best of luck!

In my case, the noise was a lower tone than the engine at idle. It was intermittent, with associated vibration. That is to say: the engine would hum along as per usual at idle and then the engine would feel and sound as if it were "bogging down," as if something were applying an undue load to the engine. If I sat in the driver's seat and placed my right hand on the middle of the dash above the seats, I could feel a noticeable vibration during the "bogging down." What was happening was that the bearings on the fan clutch bracket were so worn, the fan was unable to turn freely and smoothly-trying to stop turning, even. That, in turn, was placing more load on the drive (serpentine) belt trying to turn the mechanical fan and causing the engine to work harder to rotate everything, thus the "bogging down." It was not constant , but came and went (department of redundancy dept.?). When I removed the drive belt from the fan pulley, I was unable to appreciate any undue "play" or "wiggle" in the fan, but the fan would not rotate freely. How can I put this? It was like there was a tangle on the middle of a yo-yo string, such that the yo-yo doesn't unwind smoothly. Also, when I applied a decent amount of throttle between 35-45mph, there was a noise and vibration like when you thumb-shuffle two halves of a deck of cards together. Sorry for the length, but that is the best way I can explain. I hope this helps in some way.

I feel your pain. Replacing a drive belt on your '94 should take no more than 1min30sec. That's about how long it took me, and I don't goof with cars for a living.(I goof with them like it IS my job, though)

[prix]

Btw, wanted to thank everyone for your help. Internet diagnostics (it worked) -- maybe you are starting a trend! About prices...which others may find useful..I found a WIDE range of pricing for the fan bracket. Here's the rundown. Salvage yard (OEM, specializes in Japanese auto parts)/$125; Internet Shop (aftermarket item)/$139; Lexus dealership (Southern CA)/$341; Internet Shop (OEM)/$165; Neighborhood Gas Station (aftermarket)/$230.

Needless to say, I bought the $165 OEM part.

[prix]

I picked the car up yesterday and drove it back 20 miles or so from the (lexus-trained) indie mechanic's shop. BIG difference in the way it runs; effortlessly, is the best way to describe it. Before I left, I looked at the old fan bracket they took out, and manually tried to turn it -- almost impossible. So that explains why, in the past year or so, it felt (off and on) as if the engine had some kind of load on it. It was having to 'force' that bearing to turn.

A few more questions:

Could the engine have been damaged by driving it for so long with a bad fan bearing? In retrospect, there were 'signs' for more than a year that the bearings were failing but I did not know what to make of them so did nothing.

Could the 'too small' serpentine belt have caused any damage to the engine or other parts (pulleys, tensioner)?

[prix]

I am adding this non-Lexus link for 'clues' a serpentine belt can give to assist in a diagnosis.

http://www.cartechbooks.com/vstore/showdetl.cfm?st=0&st2=0&st3=0&CATID=21&Product_ID=3656&DID=6

[landar]

Could the engine have been damaged by driving it for so long with a bad fan bearing? In retrospect, there were 'signs' for more than a year that the bearings were failing but I did not know what to make of them so did nothing.

Could the 'too small' serpentine belt have caused any damage to the engine or other parts (pulleys, tensioner)?

The short answer is no, it would not damage your engine in the least. Now, as far as the other accessory parts, with a tight belt they felt some extra tension but are most likely fine. Don't worry about it. The fan bracket was the weak link and let you know. Glad to hear you have it fixed.