[Happy_Trails]

I just purchased a 2004 Trailblazer LS 4x4 with 88K miles. No sooner than I got it home, I noticed a rattle in the engine compartment. It seems to be at it's worse when the A/C is on. After inspection, I was sure it was the tensioner pulley on the passenger side of the motor because that is where the noise is comming from. I replaced it and I still have the noise. It sounds like the power steering pump, so I took the belt back off and tried to spin and wiggle all the pulleys under the hood and all are nice and tight with no noise like you would expect if bearings were going bad. So, with the belt back in place, I started it and listened with a screwdriver like a stethascope. I hear the rattle in both the power steering pump or the timing chain cover. I have an extended warranty that will cover the timing chain if that is it, but I want some opinions before I take it to the dealership. If it is the timing chain, is this a common problem? Any help would be greatly appriciated!

 

[the roadie]

Timing chains are a very, very rare problem, judging by threads here. I'd guess the PS pump.

 

[Happy_Trails]

Well, that is what I am hoping for. Believe me, I searched this forum pretty thoroughly before posting. I will also try the “fan clutch test” before I take it to the dealership. Thanks for the reply.:thumbsup:

 

[Happy_Trails]

One more thought, is it ok to start the engine without the serpentine belt installed. This would eliminate anything inside the engine, right? :undecided

 

[RayVoy]

One more thought, is it ok to start the engine without the serpentine belt installed.

Go ahead, won't hurt a thing.

This would eliminate anything OUTSIDE the engine, right? :undecided

I changed it to outside :laugh:, if there is no noise, the problem is in one of the belt driven accessories.

The ac compressors are prone to noise, and it is hard to track it down. The noise seems to telegraph (there's an old phone company expression) around the engine.

GM put the compressor on the bottom, lots of water and dirt :duh:

 

[Happy_Trails]

OK, everything looks like it leads to the power steering pump. I am just wondering if anyone else on here has had a power steering pump sound like a paint can rattling really fast and there be no loss in power of steering? This sound is only there at idle with the a/c on or with the a/c off and the wheels being turned, but only at idle. I also don't have the famous whine that is usually associated with a power steering pump going bad.