Jump to content
CaddyInfo Cadillac Forum

STS front end noise


mpostr

Recommended Posts

I could use some suggestions to help eliminate a front end noise in my '99 Seville STS. I get a creaking noise whenever I accelerate from a stop that sounds like a suspension creak. I also get a distinct ratcheting, creaking sound from the front end whenever I apply the brakes and stop while backing up. I have replaced the struts, strut bearings and bushings, axles, and tie rod ends, but the noises continue. I do not hear the noise if I power brake the car to rock the engine. The noises may and probably exist when driving down the road, but they are not as noticeable as when accelerating from a stop. The noises are more of an annoyance than anything. I don't believe the steering or handling is affected. My questions are: Has anyone else experienced this and solved the problem?. Do control arm bushings require lubrication? Could it be a motor mount issue? Am I looking in the wrong areas? The car has 106K miles and some of the parts I have replaced were due for replacement anyway, however, I don't want to start throwing $$ at it now replacing parts that don't solve the problems. Any help would be appreciated.

Link to comment
Share on other sites


Well you have eliminated a bunch of items already having replaced the struts, strut bearings and bushings, axles, and tie rod ends. You said, you replaced the bushings, what bushings? There are a few such as strut rod bushing, stabilizer bar bushing and lower control arm bushings (which you implied you did not replace). Which ones were replaced?

Explain ratcheting... Squeaking? How were the ball joints and how often are they greased? DRY ball joints will make a racket if you have dry metal to metal contact.

Bad stabilizer bar bushings will make noise over bumps.

Bad strut rod bushings allowing metal to metal contact will make noise on braking or direction change.

Its not likely your control arm bushings. Some people like to spray lube into the control arm bushings, but petroleum based lubes can swell the rubber and make the problem worse, lithium spray white grease should be used.

Look to see if your front end looks like this, it may not, they changed the lower control arm design at some point, I think yours has two lower control arm bushings and no strut rod was used, take a look. If you lower control arm looks like this, #4 are the strut rod bushings.

post-2998-1137946733.jpg

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Link to comment
Share on other sites

This really sounds like worn strut bar bushings. Given the amount of miles on your 99sts it's very possible. If you look at your control arms you'll notice a round bar attached to them on one end and the other end attached to the frame towards the front of the car. This is so with my 94sts and with the 96 so I'm assuming your 99 is at least similiar. Where the strut bar attaches towards the front end, it is sleeved with 2 large bushings which keeps the bar from banging the frame. Those bushings could have a wear spot allowing the strut bar to rub against the frame (metal on metal). It happened with my 94sts. Here's the link to that discussion with pictures included. I had a different user name if you haven't guessed. Hopefully you'll fine it helpful.

strut bar discussion

"Burns" rubber

" I've never considered myself to be all that conservative, but it seems the more liberal some people get the more conservative I become. "

Link to comment
Share on other sites

This really sounds like worn strut bar bushings. Given the amount of miles on your 99sts it's very possible. If you look at your control arms you'll notice a round bar attached to them on one end and the other end attached to the frame towards the front of the car. This is so with my 94sts and with the 96 so I'm assuming your 99 is at least similiar. Where the strut bar attaches towards the front end, it is sleeved with 2 large bushings which keeps the bar from banging the frame. Those bushings could have a wear spot allowing the strut bar to rub against the frame (metal on metal). It happened with my 94sts. Here's the link to that discussion with pictures included. I had a different user name if you haven't guessed. Hopefully you'll fine it helpful.

strut bar discussion

Regis, thanks for the reply. The bushings I replaced and referred to are the strut mount/bearing assembly. I have not replaced the lower control arm bushings. My suspension does not utilize a strut bar as yours does. Mine has a one-piece, aluminum "A" type control arm with polyurethane bushings. I believe it is all original equipment. The ball joint is riveted and is non-greasable. I believe the ball joint is not serviceable and the entire control arm must be replaced if the joint goes bad. It didn't appear bad to me when I inspected it as I replaced struts, axles, etc. As for the ratcheting noise - it really sounds like a ratchet - a crisp clicking ratchet. Not a creak, or a groan. ???

Well you have eliminated a bunch of items already having replaced the struts, strut bearings and bushings, axles, and tie rod ends. You said, you replaced the bushings, what bushings? There are a few such as strut rod bushing, stabilizer bar bushing and lower control arm bushings (which you implied you did not replace). Which ones were replaced?

Explain ratcheting... Squeaking? How were the ball joints and how often are they greased? DRY ball joints will make a racket if you have dry metal to metal contact.

Bad stabilizer bar bushings will make noise over bumps.

Bad strut rod bushings allowing metal to metal contact will make noise on braking or direction change.

Its not likely your control arm bushings. Some people like to spray lube into the control arm bushings, but petroleum based lubes can swell the rubber and make the problem worse, lithium spray white grease should be used.

Look to see if your front end looks like this, it may not, they changed the lower control arm design at some point, I think yours has two lower control arm bushings and no strut rod was used, take a look. If you lower control arm looks like this, #4 are the strut rod bushings.

Thanks BodybyFisher. I incorporated responses to your suggestions in a reply to Regis. I errantly thought he posted both reponses. Sorry.

Link to comment
Share on other sites

No problem

The original bushings were hard rubber not poly, if i am not mistaken. One of the complaints about poly is that they make noise. I hope that Jason posts his experience he had problems with poly If they were changed to poly before you bought the car, that could be a source of noise.

Look VERY close at the bottom of your ball joints, sometimes they are capped and you need to remove the cap to screw in a Zerk fitting and grease them. If I recall JimD did say that they started using sealed lower ball joints but check... I have seen dry ball joints make lots of noise but it tends to be during parking.

If you bounce the front end up and down manually can you elicit the noise?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Link to comment
Share on other sites

mpostr,

Do not disregard motor mounts. Power braking may not provide with enough acceleration to make the front end sound as it would when you move from a stop. Ideally power braking on a hoist with an assistant could show what is going on. Otherwise, you might want to open the hood during power braking and watch from the driver sit the engine movements. If it is excessive you will notice it.

The saddest thing in life is wasted talent

Link to comment
Share on other sites

I cannot get the car to make the noises by bouncing the front end by hand, I can however, get it to make noise by rocking it back and forth while in park. It seems to me that the engine moves quite a bit when I do this leading me to think it could be motor mounts. I understand the motor mounts are hydraulic???? If this is the case, there must be moving parts that are subject to wear and possible leakage. Then again, how much motion is built in to soften engine vibration for the "Cadillac feel". Are the mount prone to failure? How much engine movement should there be?

Link to comment
Share on other sites

I cannot get the car to make the noises by bouncing the front end by hand, I can however, get it to make noise by rocking it back and forth while in park. It seems to me that the engine moves quite a bit when I do this leading me to think it could be motor mounts. I understand the motor mounts are hydraulic???? If this is the case, there must be moving parts that are subject to wear and possible leakage. Then again, how much motion is built in to soften engine vibration for the "Cadillac feel". Are the mount prone to failure? How much engine movement should there be?

I am not familiar with your model year, nevertheless I believe the engine should not move more than 0.5" in any direction. Yes, motor mounts fail quite often.

The ratcheting noise may be caused by exhaust lines hitting body parts during deceleration because of failed mounts. BTW, you can think it comes from the front end but it's originated somewhere else.

The saddest thing in life is wasted talent

Link to comment
Share on other sites

I don't think you have dog bones on that car do you? They are 6 to 8 inch struts at the top of the radiator that hold the engine in place on acceleration.

Try this test, be VERY VERY careful, lift the hood, put the car in drive, put your foot on the brake and SLOWLY and GENTLY give it gas to see if the engine lifts abnormally. If you can have someone you TRUST do it while you watch all the better. Or you do it while someone watches the engine, but keep them CLEAR of it... I have seen stardard oriented engines JUMP up quite high with this test (429 cu in Caddy). It is certainly sounding like engine mountes however.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Link to comment
Share on other sites

PS, then put it in reverse and repeat the test...

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Link to comment
Share on other sites

I'll replace the motor mount(s) and let you know the results. Thanks for your input.

Obviously confirm that they need replacing before you do, Mike

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Link to comment
Share on other sites

I cannot get the car to make the noises by bouncing the front end by hand, I can however, get it to make noise by rocking it back and forth while in park. It seems to me that the engine moves quite a bit when I do this leading me to think it could be motor mounts. I understand the motor mounts are hydraulic???? If this is the case, there must be moving parts that are subject to wear and possible leakage. Then again, how much motion is built in to soften engine vibration for the "Cadillac feel". Are the mount prone to failure? How much engine movement should there be?

The hydraulic part is inside the mount...

Yes, they will leak when they break...

Source of problem is probably front mount.

Haven't heard of others changing other mounts on the '99 STS.

Front motor mount is not a picnic to change out.

Some say no need to remove radiator.

I did it without removing radiator, let me tell you, remove the radiator!

The engine will move fast and excessively when the mount is bad.

If you do a lot of WOT's, consider a solid mount.

good luck

my .02

Link to comment
Share on other sites

Jim, is there a disadvantage to using a solid mount? Noise transmission? Thanks, mike

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Link to comment
Share on other sites

Jim, is there a disadvantage to using a solid mount? Noise transmission? Thanks, mike

Mike,

I am only suggesting it as I managed to break my new motor mount in short order

with WOT's. Someone suggested a solid mount before. I haven't heard of transmission noise before.

Link to comment
Share on other sites

I am sorry, I wasn't clear. When I said Noise transmission I wasn't referring to the tranny, I was asking if the solid mount transferred more noise and vibration than the hydraulic mount does. I believe the hydraulic mounts are used top lessen noise and vibration.. Thanks

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Link to comment
Share on other sites

Here is a good link showing the front mount removal on a 99

http://caddyinfo.ipbhost.com/index.php?showtopic=2713

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Link to comment
Share on other sites

  • 1 month later...

FINALLY!!!! I've found and fixed the noise that has puzzled and frustrated me to my wits end. As it turns out, I should have investigated my first instincts a little further. The creaking/ratcheting noise I have been hearing from the left front suspension turned out to be the lower control arm on the RIGHT side of the car. I guess this goes to show how noises will transmit themselves throughout the vehicle. I discovered the culprit by accident (?) while jacking up the left front side to look for problems again. I noticed the car was creaking while I was jacking it up. After looking and listening several times, I went to the right side of the vehicle and noticed the front control arm bushing (which was bearing a side load due to the left side being in the air) was compressed and off-center. After taking the load off the right side the bushing returned to its normal look. However, a little pressure from a pry bar showed the excessive movement in the bushing. After replacing the control arm unit, the car now drives as quiet as it should, and probably straighter since the excess slop has been removed. Isn't it funny how when you've finally solved a problem, the solution seems like it should have been obvious? My thanks to everyone who responded to my post.

Link to comment
Share on other sites

its very well it could be the control arm i know that mine were bad since the car had 60k miles on it and i do have to oil the the hell of it that there not sercivable :(. i wish they would make the products to where they can be serviced !

michael S

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...