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'99 Eldorado
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Discussion Starter · #1 ·
Hey guys,

After 8 years of daily driving my 1999 Eldorado, I got a new car and want to begin the process of restoring my first car back to her showroom glory.

My first issue Seems like an easy one, but I wanted to verify with someone before going through with this.

When going open-throttle and shifting up a gear at near redline, I always hear an abrupt loud squeaking from inside the cabin coming from the engine bay. I haven't really noticed any issues relating to this. My thought is the belt tensioner might be going bad- it is original with 125k miles- and would like to replace it when I change the belt in the next few weeks. Has this ever happened to anyone? I've noticed this noise for close to 30k miles now. Would changing the whole assembly and belt likely fix this? It's not a very expensive replacement so figured I should just do it.
 

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2002 F55 STS, 2014 Explorer XLT, F-150s
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For a 1999 Eldorado - which model - ESC or ETC? Different engine calibrations, transmission final drive, trim levels.

If either the water pump belt or the main serpentine belt tensioner pulleys were going bad there would have been big, expensive problems long before 30Kmiles. MAYBE the main serpentine drive tensioner itself - but be careful - some have had real problems with the mounting bolts of both the tensioner assembly or the center bolt for the idler pulley.

Another thought would be the front center motor mount. They often break and allow the engine to torque way to far toward the firewall on power demands. Your car may have the dog bones (torque struts) - are they in good condition? - - - Get a trusted assistant, pop the hood. You stand at the aft front side of the fender, looking at the engine. Have the assistant start the engine, hold the service brake firmly, and put the stick in D. Holding the brake, rev the engine to 1200 - 1600 rpm. If it torques toward the firewall more than 1/2" - 3/4" then something is too loose.

Dogbones and center mounts in RockAuto. If you want a front center mount that will not fail, talk to www.northstarperformance.com.
 

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'99 Eldorado
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33 Posts
Discussion Starter · #3 ·
For a 1999 Eldorado - which model - ESC or ETC? Different engine calibrations, transmission final drive, trim levels.

If either the water pump belt or the main serpentine belt tensioner pulleys were going bad there would have been big, expensive problems long before 30Kmiles. MAYBE the main serpentine drive tensioner itself - but be careful - some have had real problems with the mounting bolts of both the tensioner assembly or the center bolt for the idler pulley.

Another thought would be the front center motor mount. They often break and allow the engine to torque way to far toward the firewall on power demands. Your car may have the dog bones (torque struts) - are they in good condition? - - - Get a trusted assistant, pop the hood. You stand at the aft front side of the fender, looking at the engine. Have the assistant start the engine, hold the service brake firmly, and put the stick in D. Holding the brake, rev the engine to 1200 - 1600 rpm. If it torques toward the firewall more than 1/2" - 3/4" then something is too loose.

Dogbones and center mounts in RockAuto. If you want a front center mount that will not fail, talk to www.northstarperformance.com.
Ah! I haven't thought about the mounts.

I have the ESC- I haven't heard these horror stories with the tensioner assembly mounting bolt- does it just strip since the block is aluminum?

One of the other projects I need to do IS the center motor mount. The rubber is rotted through and the motor definitely rocks a fair bit. I hadn't thought about that as a possibility for screeching when it shifts from redline! I know the dogbanes are good- replaced those a couple years ago. I'll give the center mount another shot and see if that stops the squealing!

As an aside, I did try doing the center mount a few months ago when doing the rear valve cover gasket- I noticed that getting the bolts at the top of the bracket in the block had a very difficult angle and the bolts were extremely tight. Any advice to make that easier? They were at such a weird angle that I had to give up the weekend project for that time. Thanks!
 

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1998 Cadillac Deville 1995 Cadillac Eldorado Touring Coupe, 1970 Cadillac Eldorado,
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My car has done the same thing for as long as I can remember. Redline-shift-squeal. I’ve changed both my tensioners (water and main drive). Since then I hear it much less than before but still happens. It’s just that extra torque going to the belt during the shift. Rainy weather doesn’t help with it either but deffinitly diagnose your moving belt parts as sub suggested.
 
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