Metal shavings in coolant?

[mz35z]

So I just flushed my coolant system. It really needed it, it was murky brown.
When I flushed it, I found a lot of small aluminum shavings at the bottom of my flush pan.

I immediately thought it was my water pump, but I want to know for sure.
I have also been hearing something like a knocking sound coming from my engine. I can't tell where exactly it's coming from, but it sounds like it's coming from the water pump.

Is there anyway I can know for sure what the shavings came from?

 

[Rearanger]

You've answered most of your own questions.

Is there anyway I can know for sure what the shavings came from?

Remove the water pump.

 

[Big Jim M]

What RR said times two! Unless the shavings were LEFT in there from the factory, the only place they COULD come from is the pump.
Big JIm

 

[schmoo]

the last time i had these symptoms, i found that some idiot
had knocked one of the soft plugs in when putting in a
block heater. it moved around in the motor and sucked
up against the water pump.

 

[mz35z]

Thanks guys. I just wanted to make sure I could conclude that it was the water pump. I don't want to take it all apart to find out it's something else.

 

[Psychopete]

I don't want to take it all apart to find out it's something else.

LOL it happens - had to replace a lower intake on a Chevy 3.1L, customer said another mechanic diagnosed that it was the lower intake. Common enough that I went a head with it. Turns out it was a leaky timing cover gasket, leaking internally into the oil.

 

[mz35z]

Haha, that sucks!

Another thought I had... Could it possibly be a cooling system sealer? Doesn't that sometimes contain aluminum shavings?

 

[Rearanger]

... Could it possibly be a cooling system sealer? Doesn't that sometimes contain aluminum shavings?

Why, did you use one?

 

[mz35z]

No, I have not used any sealant. Nothing has been added to the coolant since the last owner... I don't have any means of contact with him either...

 

[fourwheelford]

Replace the pump, your coolant is probably murky brown for a reason and thats probably it. Coolant should never look like that at any time it usually means there is some corrosion somewhere in the system. One question though, are you sure they are aluminum? Very small steel can look shiny like aluminum, take a magnet to it to be sure.

 

[mz35z]

I will try the magnet. What if it is steel? Does that mean a worse off problem?

 

[Big Jim M]

Doesn't matter what it is in the coolant... The only place it could come from is either the pump or shavings from the factory! Nothing else is moving in the coolant, so there is nothing to produce the shavings cept the pump.
Big JIm

 

[fourwheelford]

I only mentioned the magnet because I think the water pumps are steel I have seen the fins rotted off before. So if the shavings are not magnetic they could be from somewhere else. There are many different types of metal on these motors including the radiator which has a lot of brass and not magnetic. I think water pump but im just offering up some trouble shooting stuff for the guy.