89 Mustang 5.0 fuel pump noisy

Chances are the pump is working too hard. Try changing the inline fuel filter (if it has one) first and see if it goes away. If not,unless the noise is normal for this model, I don't know, replace the pump or you will be stranded shortly.

A mechanic gave me a tip about extending the life of electric, in the tank, pumps and that is never let your fuel level go below 1/2 or at worst

When the pump in my 89 LX got loud enough to notice all the time it lasted about another 8 months and started going bad. When you change it, go ahead and use a high output, because when you do decide to do anything to it you don't want to have to do it again. Pump replacement is really quick and easy, it's getting the cover on and of that's a real PITA.

I still say this is crap. It's the fuel flowing THROUGH the pump that cools it. .. the advice about (partially) clogged filter is good, though, for exactly that reason.

I tend to agree, but it can't hurt :)

The fuel flowing through the pump goes right through the motor (believe it or not, sparks from the electrical motor and all!) and acts as a coolant as well as a lubricant.

The reason the entire thing doesn't explode is because there is no O2 in motor.

Every pump I have ever changed is covered by a neoprene sock which doesn't absorb liquid very well as far as I can tell. IOW it's not soaking wet to the point where you have to wring it out like a sponge when you remove the pump from the tank so how much fuel really comes in contact with the outside of the pump?

I dunno???

At any rate, running a tank low is a bad idea in any case. A clogged fuel filter will cause pump whine and ultimate failure as well.

Yeah, when they start to whine, I'd replace it before you get stuck. Even under the best of circumstances the OEM pumps on the Fox mustangs were somewhat loud, but that seems overly loud and a legitimate source of concern.

Cheers,

I replaced mine a few years ago. Too noisy. Nice and quiet since. I would also replace the relay under the driver seat. Fred

That's a very good piece of advice because pumps that are working too hard can draw more current and fry the contacts on the relays controlling them.