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2006 DTS
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Discussion Starter #1 (Edited)
Remembering the best part of click and clack the Tappet brothers radio show was “Stump the Chump”, where the hosts would have to guess what the Root cause of a cars problem was by simple process of elimination.

I’m faced with such a problem that I’m hoping someone can guess before I have to start taking things apart and gitten dirtied up.

The temperature has been upper 90’s. No issues during the first part of the drive. Took the heated up DTS through a car wash. Pulled out at the end of wash with no issues. Went through a fast food drive thru and sat idling over 20 minutes.

Drove off. Slight popping noise as I pulled off. Each time I accelerated it would pop again. Went forward and reverse. Popping going forward, not in reverse, no popping going left or right. Pulled on suspension parts nothing obvious loose. Seemed to transmit in steering but not sure.

Felt cause may be coming from input shaft or a motor/ transmission mount. It made no noise in turns so I am preliminarily assuming it’s not CV joint. It was too hot to mess with that day so after duplicating the noise a few more times I put the DTS in storage and pulled out my old Truck.

Purchased a front motor mount just in case to have ready to take to my local mechanic to diagnose. I knew the splash cover would have to come off to even come close to verifying if that part was the problem.

Picked up DTS a week later to get ready for mechanic. No noise, accelerate full throttle, half throttle, forward, backward, Fast figure 8’s, hard stops, starts, 100+ miles later.... nothing. Nothing making noise, nothing dragging. Loaded with passengers or not, still no noise. AND no debris of any kind was remaining where the car was stored.

Within 5,000 miles:
New premium Strut assemblies
New Control Arms
New ball joints
New Tie rods
New Rotors OEM
New Brakes OEM

Within 25,000 miles
Front and rear motor mounts,
Top Torque mount

With out climbing under it Im stumped. I know that no issue that makes a mechanical noise like that just “Goes away”

Anyone experienced anything similar before, that just went away? I know chasing these issues can be a PITA, but I also don’t want to just wait till it comes back to diagnose it. My best guess under normal circumstances would be a strut mount, dry ball joint, tie rod etc. and I know that new parts go bad, but to just disappear?

Only clues I have:

  • Railroad track with some good suspension shake before Car wash,
  • HOT environment,
  • water spray,
  • long idling,
  • problem noise comes
Then
  • Car sits for a week un driven,
  • noise goes away.
  • all effort to reproduce comes up with nothing.
This Chump is stumped
 

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96 FWB
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...... Slight popping noise as I pulled off. Each time I accelerated it would pop again. Went forward and reverse. Popping going forward, not in reverse, no popping going left or right. ......

Felt cause may be coming from input shaft or a motor/ transmission mount. It made no noise in turns so I am preliminarily assuming it’s not CV joint. ......

.......
I think you're interpreting the, "It made no noise in turns so I am preliminarily assuming it’s not CV joint" incorrectly. The greatest wear on a CV over time is going to be in the 'under load', 'straight' and 'forward' profile. Tolerances will be relatively tighter in reverse and with the wheel anywhere off-center.

Any cracked boots would be a great place for the elements to get in and contribute to sporadic misbehavior.
 
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2007 DTS
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71 Posts
Not sure how many miles you have on the vehicle...but I stopped trying to fix what is not broke years ago. The new parts even AC Delco are not the OEM quality. So I only grease the squeaky wheel and I don't proactively do maintenance other then oil lubrication & fluid changes. Brakes shocks tires bushings will be obvious.

What you are describing sounds very much like my struts did before getting them replaced.

Good luck and please keep us updated...
 

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2005 Base CTS work at Pullen solenoids Glass Factory for 36 and a half years
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A rock possibly got kicked up somewhere and got ground way or fell out just before you parked it.

Roy
 

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2006 DTS, 2006 DTS
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118 Posts
Were your brake caliper bracket slider bolts cleaned and re greased with new brakes? I had a creaking front end noise I couldn't figure out until I did the brakes. New pads, new rotors, greased slider bolts. No noise no shake nothing but smooth braking. If they are dry, upon release and acceleration may be making the popping noise?
 

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2006 DTS
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Discussion Starter #6
That’s one I thought about initially, and I greased everything with synthetic brake grease, used new boots, pins springs greased all pins, slides. One thing you have me thinking is the possibility of a stuck caliper. They were plenty warm when they went through the car wash, and perhaps the dousing of water caused one of them to seize temporarily.

Side note, When I did the entire front end, (control arms, ball joints, tie rods, stabilizer links, struts, brakes, rotors) I torqued every fastener to spec and torque striped every bolt afterwards so I could be sure I didn’t under or over torque something that would have me chasing this type of issue in the future.
 

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Discussion Starter #7
A rock possibly got kicked up somewhere and got ground way or fell out just before you parked it.

Roy
That’s what I was thinking or rather hoping, but where would the rock have to be wedged to only clunk on acceleration forward but not reverse? The engine bay and underbody of the DTS is a very busy place and hard to see very much without pulling stuff apart.
 

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Discussion Starter #8
I think you're interpreting the, "It made no noise in turns so I am preliminarily assuming it’s not CV joint" incorrectly. The greatest wear on a CV over time is going to be in the 'under load', 'straight' and 'forward' profile. Tolerances will be relatively tighter in reverse and with the wheel anywhere off-center.

Any cracked boots would be a great place for the elements to get in and contribute to sporadic misbehavior.
I’m going to check, but I do t drive her much, never in the winter and the Boots were in excellent condition last I checked. I agree on the average loading on the joint principle, and the sound was a pop / clunk.

All those suspension parts I replaced have zero grease fittings. I’m going to get under it this weekend and check boot conditions and grease up the fittings to eliminate possibility of a dry joint.
 

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I’m going to check, but I do t drive her much, never in the winter and the Boots were in excellent condition last I checked. I agree on the average loading on the joint principle, and the sound was a pop / clunk.

All those suspension parts I replaced have zero grease fittings. I’m going to get under it this weekend and check boot conditions and grease up the fittings to eliminate possibility of a dry joint.
I had an 03 Monty SS for 13 years, run great. Only problem I had was hub assembly and cv axles, because of the 20" chrome rims I put on it the second day I had it. The noise you are describing sounds just like the noise I would hear when a cv axle start to go bad. I replace my axle 4 times in 13 years.

Sent from my SM-G981U using Tapatalk
 

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Discussion Starter #10
Went under the beast today to grease then all joints and tie rods. No torn ball joint toe rod or CV joint boots, no leaking or torn trans or motor mounts that I could see. This sucks. I want to know!
 

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2005 Base CTS work at Pullen solenoids Glass Factory for 36 and a half years
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Just because something isn't leaking doesn't mean that a part is not worn out. When you test by grabbing the wheel to try and move it you are probably only applying let's say a hundred pounds of force and when the vehicle is applying force it's a couple thousand pounds. When you torqued everything was it under load or hanging in the air? Suspension parts should be torqued once they are under load.

Roy
 

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Discussion Starter #12
I final Torqued the control arms and top strut bolts under load. The rest on jack stands. First time I ever heard that for other suspension components.

I know in General assembly departments in auto plants they don’t torque under load because that would require that they be torqued on the “flat track” when the vehicle is sitting on its tires. That can’t happen because there are no pits for workers to be in on the fast track line.
 

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Remembering the best part of click and clack the Tappet brothers radio show was “Stump the Chump”, where the hosts would have to guess what the Root cause of a cars problem was by simple process of elimination.

I’m faced with such a problem that I’m hoping someone can guess before I have to start taking things apart and gitten dirtied up.

The temperature has been upper 90’s. No issues during the first part of the drive. Took the heated up DTS through a car wash. Pulled out at the end of wash with no issues. Went through a fast food drive thru and sat idling over 20 minutes.

Drove off. Slight popping noise as I pulled off. Each time I accelerated it would pop again. Went forward and reverse. Popping going forward, not in reverse, no popping going left or right. Pulled on suspension parts nothing obvious loose. Seemed to transmit in steering but not sure.

Felt cause may be coming from input shaft or a motor/ transmission mount. It made no noise in turns so I am preliminarily assuming it’s not CV joint. It was too hot to mess with that day so after duplicating the noise a few more times I put the DTS in storage and pulled out my old Truck.

Purchased a front motor mount just in case to have ready to take to my local mechanic to diagnose. I knew the splash cover would have to come off to even come close to verifying if that part was the problem.

Picked up DTS a week later to get ready for mechanic. No noise, accelerate full throttle, half throttle, forward, backward, Fast figure 8’s, hard stops, starts, 100+ miles later.... nothing. Nothing making noise, nothing dragging. Loaded with passengers or not, still no noise. AND no debris of any kind was remaining where the car was stored.

Within 5,000 miles:
New premium Strut assemblies
New Control Arms
New ball joints
New Tie rods
New Rotors OEM
New Brakes OEM

Within 25,000 miles
Front and rear motor mounts,
Top Torque mount

With out climbing under it Im stumped. I know that no issue that makes a mechanical noise like that just “Goes away”

Anyone experienced anything similar before, that just went away? I know chasing these issues can be a PITA, but I also don’t want to just wait till it comes back to diagnose it. My best guess under normal circumstances would be a strut mount, dry ball joint, tie rod etc. and I know that new parts go bad, but to just disappear?

Only clues I have:

  • Railroad track with some good suspension shake before Car wash,
  • HOT environment,
  • water spray,
  • long idling,
  • problem noise comes
Then
  • Car sits for a week un driven,
  • noise goes away.
  • all effort to reproduce comes up with nothing.
This Chump is stumped
I have 2007 dts. Same issue. I replaced both front springs. No problem now.
 

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There was a GM bulletin about steering shafts making a noise intermittently similar to what you described..
possibility. Temperature affects noises a lot more than people think. You said you idled for twenty minutes
at a drive-thru... bet things were toasty under the hood. can't believe you waited at a drive-thru for 20 minutes
 

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Check that you have all of the flange bolts present in the drive shafts. Had one snap off and go missing, the keeper extended out and hit the body lightly only when engine torqued. Had to put all 4 wheels clear and run to find it.
 

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2006 DTS
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Discussion Starter #17
Update 7/27/20. Popping Clunk disappeared over 2 weeks ago. Drove through 2 full tanks of fuel without it reappearing. Saturday, drove through the same car wash as the day when the Clunk popping issue emerged.. After exiting the car wash the popping was there again, much quieter than the first time, but stiil there and felt in the column.

one hour later , popping gone. The trigger is the water in the car wash. Want to investigate the input shaft. Will post results.
 

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Discussion Starter #18 (Edited)
Issue solved. Popping noise was the Intermediate Steering Shaft. Known weak GM design.

Here is the result:
  • Popping noise - Gone
  • Light steering feel - Gone, resistance feels just right.
  • Highway speed driving / handling - feels much tighter over all.
  • No more clunk noise driving over road irregularities or going over rounded curb into driveway
Dorman replacement - upgraded design. Heard from multiple forums it was a PITA job, didn't want to spend time under the car or under dash, so had my mechanic install.

$124 Part from Amazon, $200 labor

Could have driven tolerating these annoyances forever, not a safety issue. Given the results, I would consider dumping the factory ISS and installing this modified design to be a high priority DTS upgrade or mod (at least for the 2006 DTS)
 

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Interesting to learn the shaft goes through the firewall = seems unnecessarily complicated. But glad you got to the bottom of it for your model and it wasn't CVs.

Creds for checking back in.
 

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2007 DTS
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I had a concerningly loud "pop" upon acceleration and occasionally when braking hard almost the whole time I had my car, my subframe bolts weren't loose, but upon lowering one side of the subframe to do the timing chains when I put everything back it hasn't done it one time since... I loosened all and removed some of the bolts. I dunno, maybe worth a shot I had changed almost everything in the front before this also, struts, mounts, LCA's, links, bushings, ties etc etc. I was just gonna live with it but sometimes things work out....
 
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