running engine without serpentine belt

[pm26]

I would like to remove the serpentine belt (drives alternator, water pump and power steering) and run engine at idle and rev it up a little for several seconds. This will help me pinpoint (hopefully) whining noise I suspenct is coming from the alternator or idler bearings.

 

I really do not thing anything will be harmed, but will I get a check engine light (alternator not driven by belt)?

 

Does anybody has expeireince with whining bearings etiher on the laternator or either belt idler?

[abogoto]

mine had a whine/grind sound sort of like it needed oiling, I'm talking about the idle pully. when I changed it had no more sound. I also had a noise from my airconditioner that made it hard to pinpoint so I to use a stethoscope device, and found the noise right away.

[Deere_Daze]

I hope you dont plan on running the engine like that for long because with no powe from the alternator the engine wont be able to run long solely on battery power.

Also, make sure that your oil pump isnt driven by that pump too.

[Mr. Smith]

I would like to remove the serpentine belt (drives alternator, water pump and power steering) and run engine at idle and rev it up a little for several seconds.  This will help me pinpoint (hopefully) whining noise I suspenct is coming from the alternator or idler bearings.

 

I really do not thing anything will be harmed, but will I get a check engine light (alternator not driven by belt)?

 

Does anybody has expeireince with whining bearings etiher on the laternator or either belt idler?

 

<{POST_SNAPBACK}>

 

 

 

 

Run it, wont hurt it a bit as long as you do it on a cold motor. i changed both tensioner and idler pullies on my 97 for roughness. The alternator should be for whining bearings but im to d**n cheap to pony the cash up for a new one.

 

You won't get a SES by runing without a belt unless something craps out.

[Mr. Smith]

I hope you dont plan on running the engine like that for long because with no powe from the alternator the engine wont be able to run long solely on battery power.

Also, make sure that your oil pump isnt driven by that pump too.

 

<{POST_SNAPBACK}>

 

 

 

 

Um they have an internal oil pump, in fact I can't remember an American car built in the last 40 years with an external pump.

 

Actually you can go for a good while on just battery power. It is using the accessories that will kill the battery faster.

[rjirvine]

You can use a long screwdriver or a few socket extensions put together and use that instead of a stethescope. Just put the end of the screwdriver on the component and the other end up to your ear. That should help diagnose the alternator and the AC compressor. Just be careful of the fan and the belt while you're doing this. If it turns out to be the tensioner or idler pulley, they are very easy to change and aren't too expensive.

[dewfpo]

A long large diameter hose can work as a stethoscope as well. Just place it on a non-rotating part of each rotating mass and you will find you whine. Just be very careful.

 

DEWFPO

[pm26]

Thanks for the replies, I actually bought a mechanic's stethoscope for $ 5 recently, so I will use that. Because this is a throttle by wire arangement (no accelerator cable), I will need somebody to rev up the engine a little. (Or, is there a way to accelerate it from inside the engine compartment)? I will perform the stethoscope test with the serpentine belt in place, of course.

 

There is an automatic spring loaded tensioner which keeps the serpentine belt tight, and there is an idler pulley. How much does it cost to replace these? If I found the problem with one of these and the parts are not expensive, I would just buy the part and install it, even though the truck is under warranty. It is not worth my time to take it in for a $ 20 repair. Somehow I do not think that these parts are so cheap though. I paid about $ 70 for one idler pulley for my Mazda 626.

 

From the responses it looks that the idler pulley bearings are likely culprits here.