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I have a 2007 Buick Lucerne with a 4.6L Cadillac Northstar engine As you guys all know it overfills the engine bay and is a complete nightmare for changing parts especially the alternator where 50% of the car has to be dismantled.I want to change the serpentine belt so I need to know what I am up against.The vehicle is lightly used with only 65,000 miles on it. Any help especially diagrams or procedures would be most helpful. Thanks in advance
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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At 65,000 the belt should look close to new. What problems do you have that make you want to change the belt?

There's a tab on the belt tensioner hub with a square hole for a 3/8 or 1/2 socket wrench (I forget which size). Lever the tensioner to relieve belt tension and slip it off the P/S pulley. Patience, tools, magic words.

Belt routing and pulleys.gif
 
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Discussion Starter #3 (Edited by Moderator)
I am giving the car to my son. I want it to be in the best possible condition and not have him worry about maintenance /repair items too soon. Having said that how long is this serpentine belt good for?

I also have a whirring sound when I start the car and it continues for awhile after I shut down the engine. Sounds like some pulley freewheeling? Any thoughts?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Where is the whirrr located? Engine compartment, cabin, trunk, under the rear? Fan noise?

I doubt you'll get much good Buick info in these Cadillac forums.
 

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Discussion Starter #5
The whirring noise is coming from the engine compartment almost like a rotating pulley bad bearing or bushing.
So i'm thinking idler pulley, tensioner pulley, ac compressor. I do not suspect the alternator as I have replaced many and haven't heard anything like this from an alternator. It's like the whirr of a jet engine taking off. I asked questions on this forum because of the Cadilac Northstar Engine 4.6 L
 

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I am giving the car to my son. I want it to be in the best possible condition and not have him worry about maintenance /repair items too soon. Having said that how long is this serpentine belt good for?

I also have a whirring sound when I start the car and it continues for awhile after I shut down the engine. Sounds like some pulley freewheeling? Any thoughts?
First thing that comes to mind is electric fan
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Normally the Northstar cooling fans do not run after engine - OFF except if the engine is seriously overheated. Otherwise they run in SLOW if the coolant gets to 224 degrees; FAST at 236. The fans run in SLOW any time some A/C compressor function is set and usually don't run at over 30 mph - not needed.

Or something is causing the AIR blower to run all the time - but it's only supposed to run for short periods at cold start to quickly light off the cat.

A pulley would not be heard for more than 3 - 4 seconds after engine - OFF if the belt had any tension at all.

Does a Buick Northstar install use an electric coolant pump?
 
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