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1995 SEDAN DEVILLE-4.9 & 1978 SEDAN DEVILLE-425
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1,673 Posts
Discussion Starter #1
Got a squeaky noise on cold starts from belt area.
When engine gets warm noise stops.Had a new belt installed 6 months ago and no squeaky noise for that time
until now.
Took it into my mechanic today and he says the belt tensioner is sticking and belt is good.
I tried moving the tensioner myself with proper tool when I got home and it does sort of stick but it still moves
ok when tension is applied.
Is the tensioner supposed to freely without any sticking sounds when moved?
If it is sticking would that be the source of the squeaky noise when engine is cold?
 

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2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
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26,323 Posts
Yes, the tensioner should move smoothly. If it's sticking, the squeak could be he belt slipping. However, it could also be the tensioner pulley or idler pulley. The tensioner will come with a new pulley, I'd suggest spending another ~$15-$25 and replace the idler pulley as well. Cheap preventative maintenance on a 20 year old car.

FWIW, sometimes spraying the pivot of the tensioner can free it up, I personally wouldn't bother considering the age.
 

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1995 SEDAN DEVILLE-4.9 & 1978 SEDAN DEVILLE-425
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Discussion Starter #3
Yes, the tensioner should move smoothly. If it's sticking, the squeak could be he belt slipping. However, it could also be the tensioner pulley or idler pulley. The tensioner will come with a new pulley, I'd suggest spending another ~$15-$25 and replace the idler pulley as well. Cheap preventative maintenance on a 20 year old car.

FWIW, sometimes spraying the pivot of the tensioner can free it up, I personally wouldn't bother considering the age.
Thanks for the info---my mechanic sprayed the tensioner pivot with some lube and it moves a little better---he said it might take a couple
days for it to penetrate.
If I have to replace both tensioner and idler pulley---is that a do it yourself job? I can get parts locally and prefer to do
what I can on my cars myself.
I`ve got the right diagram for the proper belt installation.
 

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1991 Cadillac Brougham D'Elegance 5.7 Litre, 1994 DeVille
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6,796 Posts
If spraying it with oil stops the noise it's time to replace those parts, the oil is only going to be a temporary fix. The parts are cheap. Yes it is a do it yourself job.

The diagram for the belt is on the sticker under the hood.
 

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1995 SEDAN DEVILLE-4.9 & 1978 SEDAN DEVILLE-425
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1,673 Posts
Discussion Starter #5
If spraying it with oil stops the noise it's time to replace those parts, the oil is only going to be a temporary fix. The parts are cheap. Yes it is a do it yourself job.

The diagram for the belt is on the sticker under the hood.
The diagram for the belt under my hood is wrong for some reason. Many mechanics have been puzzled when trying to get the belt
on using that diagram, so I always have copies of the correct diagram in my trunk when they need it.
Hopefully I`ve got right tools to do it myself.
Thanks
 

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1991 Cadillac Sedan deVille
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591 Posts
The diagram for the belt under my hood is wrong for some reason. Many mechanics have been puzzled when trying to get the belt
on using that diagram, so I always have copies of the correct diagram in my trunk when they need it.
Hopefully I`ve got right tools to do it myself.
Thanks
They probably didn't read the diagram correctly. To read it correctly you need to be facing the belt, not the radiator.

I also question how experienced those mechanics are not being able to understand how the belt routes. You don't even need to look at the diagram to figure it out. It's that simple.
 

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1995 SEDAN DEVILLE-4.9 & 1978 SEDAN DEVILLE-425
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Discussion Starter #7
They probably didn't read the diagram correctly. To read it correctly you need to be facing the belt, not the radiator.

I also question how experienced those mechanics are not being able to understand how the belt routes. You don't even need to look at the diagram to figure it out. It's that simple.
Wow--facing the belt and it reads right---thanks I`ll remember that for sure!
 

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1992 DeVille
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2,339 Posts
The idler is a bit of a bitch to get at with Ac lines in the way but just be careful and if you have a bad back and can kneel when working that'll save your back.

Tensioner is super easy. Once the 13 mm bolt is off, you'll need to rotate the assembly clockwise to get the tensioner pulley above the Ac lines for removal. Also be careful when pulling the tensioner assembly off because those ac lines make for a tight fit and a few millimeters of overlap so you might need to use a little gentle love yank when slipping it off and putting the new one on.

I had a squeak when cold and a rough rubbing sound at idle on cold mornings and thought it was a lower engine noise, a crank issue, or God forbid, the tranny but after changing both the idler pulley (didn't make a huge difference) and the tensioner and tensioner pulley the noises pretty much went all away.


A big tip is when you're applying force to the tensioner assembly to release the belt (which would be a vertical motion in relative comparison to the ground), look for any horizontal movement in the assembly. If there is much side to side play, that puppy should be replaced. Mine only had 40k miles on it. The tensioner pulley surface was warped a bit from the belt too. The new one was perfectly smooth
 

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1995 SEDAN DEVILLE-4.9 & 1978 SEDAN DEVILLE-425
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Discussion Starter #9
I`m getting the belt tensioner and idler pulley replaced with new on Monday by my trusted mechanic.
I`d try to do it myself but I`m still healing after getting 5 stitches recently after catching the moving fan blade on my '78
Deville with 1 of my left fingers on the joint while trying to clean the A/C belt. Went down to the bone and just missed the tendon
and nerve.
Had to go to emergency with it wrapped in a blood soaked rag.
Should have had the engine off first.
 

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1992 DeVille
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2,339 Posts
pompste said:
I`m getting the belt tensioner and idler pulley replaced with new on Monday by my trusted mechanic. I`d try to do it myself but I`m still healing after getting 5 stitches recently after catching the moving fan blade on my '78 Deville with 1 of my left fingers on the joint while trying to clean the A/C belt. Went down to the bone and just missed the tendon and nerve. Had to go to emergency with it wrapped in a blood soaked rag. Should have had the engine off first.
Had a friend have a similar incident with the chain of his motorcycle

----------

He coined a new phrase after the incident: "hey gimmie a high four and a half!!"
 

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1995 SEDAN DEVILLE-4.9 & 1978 SEDAN DEVILLE-425
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Discussion Starter #11
Got the new belt tensioner and idler pully installed on Monday and all is well so far.
Good thing I did`nt try to do it myself since my mechanic had a hell of a time getting the tensioner off.I was right there helping him with it.
For some reason the original tensioner was much "wider" than the new one and he had to remove the A/C line clamps to move the line
enough so the tensioner would clear the line.
New one went on easy and does not stick at all.
The "wider" part of the original is where the internal spring is encased.
Seems they redesigned it and is narrower now.
 

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1992 DeVille
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pompste said:
Got the new belt tensioner and idler pully installed on Monday and all is well so far. Good thing I did`nt try to do it myself since my mechanic had a hell of a time getting the tensioner off.I was right there helping him with it. For some reason the original tensioner was much "wider" than the new one and he had to remove the A/C line clamps to move the line enough so the tensioner would clear the line. New one went on easy and does not stick at all. The "wider" part of the original is where the internal spring is encased. Seems they redesigned it and is narrower now.
Yeah I replaced mine a few weeks ago. It was a tight spot to get off but I managed without having to disconnect the Ac lines. Putting the new one on was still a tight fit but easier than getting the old one off.

Hope you snugged those Ac bolts back on =P
 

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1995 SEDAN DEVILLE-4.9 & 1978 SEDAN DEVILLE-425
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Discussion Starter #13
Yeah I replaced mine a few weeks ago. It was a tight spot to get off but I managed without having to disconnect the Ac lines. Putting the new one on was still a tight fit but easier than getting the old one off.

Hope you snugged those Ac bolts back on =P
He just had to remove the A/C line "clamps" and he put them back on after new tensioner was installed.
And yes,the clamps bolts are snugged.
 

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1992 DeVille
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pompste said:
He just had to remove the A/C line "clamps" and he put them back on after new tensioner was installed. And yes,the clamps bolts are snugged.
I had just spend 300 on my Ac recharge and was worrying when I ran into the tight space with those lines. All is well though. No r12 leaked to the atmosphere haha
 

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2002 Cadillac DHS, 1995 Cadillac Sedan DeVille, 2016 Toyota Prius 4 Touring, 2010 Mini Cooper Conv.
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2 Posts
The idler is a bit of a bitch to get at with Ac lines in the way but just be careful and if you have a bad back and can kneel when working that'll save your back.

Tensioner is super easy. Once the 13 mm bolt is off, you'll need to rotate the assembly clockwise to get the tensioner pulley above the Ac lines for removal. Also be careful when pulling the tensioner assembly off because those ac lines make for a tight fit and a few millimeters of overlap so you might need to use a little gentle love yank when slipping it off and putting the new one on.

I had a squeak when cold and a rough rubbing sound at idle on cold mornings and thought it was a lower engine noise, a crank issue, or God forbid, the tranny but after changing both the idler pulley (didn't make a huge difference) and the tensioner and tensioner pulley the noises pretty much went all away.


A big tip is when you're applying force to the tensioner assembly to release the belt (which would be a vertical motion in relative comparison to the ground), look for any horizontal movement in the assembly. If there is much side to side play, that puppy should be replaced. Mine only had 40k miles on it. The tensioner pulley surface was warped a bit from the belt too. The new one was perfectly smooth
I am in the process of replacing the tensioner and serpentine belt right now (already replaced the other pulley). You are absolutely correct, the tensioner doesn’t want to clear the A/C line and I’m afraid of putting to much pressure on the line for fear of breaking something. Any tips, pics, videos would be extremely helpful. The new one is a lot thinner and should slip on easy. The pulleys had been making a lot of noise over the past year but as it didn’t seem to affect anything, I didn’t bother until now as the serpentine belt began to rip apart (didn’t break but one area in particular is badly frayed off to the side and you can see a lot of missing rubber along that edge. Here’s the weird thing..... the other night when I discovered the belt I took the car straight home where it didn’t move until I had all the needed parts ready to go. However when I was just getting started, upon opening the hood, I noticed a pretty decent coating of oil all along the old belt?!? Any clue what might have caused this? I didn’t see an obvious source as it had spattered onto various areas under the hood on that side of the engine. I’m going balder more and more each day pulling out what’s left of my hair with this one. By the way, do you happen to know the torque specs for the tensioner bolt? Thanks!
 

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White Diamond '03 DHS (with DTS floor shift)
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However when I was just getting started, upon opening the hood, I noticed a pretty decent coating of oil all along the old belt?!? Any clue what might have caused this?
Not sure which car you are talking about (you have 2 listed), but either way, are you sure it is oil on the belt? My guess would be coolant and coolant (at least Dex-Cool) does not play well with serpentine belts. It will cause them to delaminate.
 

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2002 Cadillac DHS, 1995 Cadillac Sedan DeVille, 2016 Toyota Prius 4 Touring, 2010 Mini Cooper Conv.
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Hi,
Thank you very much for your response. It’s the 1995 DeVille with the 4.9 V8.
It’s definitely oil, not coolant as there is no green color and no coolant smell. More of an old oil brown color. There was never any oil on the belt before that night. I still need to take out the old belt tensioner as I haven’t done anything with it since my last post. Here is a video showing the oil:
 
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