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Serpentine problems

serpentine belt has fallen off and the check engine light came on and engine immediately began to run rough and without power

Yes, all that can happen when the belt falls off. The serpentine belt typically drives all accessories, including the most important water pump. Once the water pump stops turning, the engine will overheat RAPIDLY. Driving on an overheated engine does very expensive damage.

It also drive the alternator which supplies power to the battery. Power drops and it will run poorly until it dies. You don’t say the make, year and model of car. The water pump on cars with a timing belt is driven by the belt.

Serpentine belts do not simply fall off. You have a component that’s failed and caused the serpentine belt to slip off. A good independent mechanic will find out what that is and get you right back on the road.

@knfenimore‌, ‘The water pump on cars with a timing belt is driven by the belt.’ I cannot disagree with you more. I’ve worked on many models with timing belts and have only seen a few models use the timing belt to drive the water pump. It is fairly rare in my experience.

@BustedKnuckles‌

My 1995 Corolla with the 7A-FE engine had a timing belt driven water pump

My 2005 Camry with the 1MZ-FE engine has a timing belt driven water pump

My brother’s 1997 Mazda had a timing belt driven water pump

“It is fairly rare in my experience.”

Exactly

It is fairly rare in your experience, but not in my experience

This just shows that each of us brings something different to the table

I was going on my 99 Camry V6.

@db4690,

My 1992 Mazda Protege did not have a timing belt driven water pump, but did have a timing belt.

My 1992 Toyota Celica does not have a timing belt driven water pump, but does have a timing belt.

My 1988 Toyota Supra does not have a timing belt driven water pump, but does have a timing belt.

My cousins 1997 Volvo did not have a timing belt driven water pump, but did have a timing belt.

The 1998 Cadillac Catera does not have a timing belt driven water pump, but does have a timing belt.

So the blanket statement ‘The water pump on cars with a timing belt is driven by the belt.’ Is not always true.

@BustedKnuckles‌

Hold your horses, partner

I never said all cars with a timing belt use the timing belt to drive the water pump

My 1994 Tercel has a timing belt, but it doesn’t drive the water pump

Yes, I know there are plenty of cars with a timing belt, where the water pump is driven by the accessory drive belt, not the water pump

But there are plenty of cars where the timing belt DOES drive the water pump

the one who did make that statement you mentioned is @knfenimore‌

Go back and read his statements

Talk to him about it. You’re literally barking up the wrong tree

On my GMs, I have had the bushing in the water pump wear causing the pump pulley to go out of plane, which then can throw the belt off. No warning and wouldn’t even stay on for a minute. Should be able to detect a little play in the pulley if that’s the case. At any rate any worn component could cause it to jump off but I have had the water pump failure on two different cars.

I get it. It just depends on the engine. My newer Toyotas have serpentine driven water pumps.

To return to the OP’s original question (actually it wasn’t a question…). this mystery vehicle should not be driven as-is.

You need to have it towed to a competent mechanic, rather than driving it.

The tell-tale signs of a significant problem include…

The serpentine belt “fell off”.
Did it actually fall off, or did it snap?
If the belt fell off, that indicates a need to replace some parts in addition to the belt, but…
in any event…your car will overheat and you will kill the battery if you start the engine and attempt to drive the car at this point.

It is "running rough"
This is almost surely the result of having a non-functional alternator, in the wake of the loss of that belt.

The Check Engine Light is lit up.
More than likely, the CEL is indicating the same thing as what we already know, but since we don’t know the maintenance history of this mystery vehicle, that is just a guess.

Have the car towed to a well-reputed independent mechanic.
Do NOT have it towed to Midas, Meineke, Monro, Sears, Pep Boys, AAMCO (God forbid!) or any other chain-run operation unless you want to pay higher prices for sub-standard repairs, some of which may not actually be necessary.

@VDCdriver‌

heh heh heh . . . ?!

Calm down, @db4690, I took your listing if cars to be a challenge, so I responded with my own list. If misconstrued, that’s on me. I think we can both agree the blanket statement was misleading, which was the main thrust of my response to @knfenimore‌. If the tone seemed aggressive, just watch this video to see how tone can be totally misread. WARNING, some adult language. Uncensored - Key & Peele - Text Message Confusion: http://youtu.be/naleynXS7yo

@BustedKnuckles‌

No, it wasn’t a challenge

Definitely don’t want to let young kids watch those two guys . . .

Agree that OP should not drive the car until this is resolved by their mechanic. For the sake of the wallet.