I'll Take "Pinpoint My Knock" for $250, Alex

[bretamo]

My 92GT has a knock that has the rhythm and sound like a rocker arm hitting a valve cover, but I cannot pinpoint where it is coming from.

The knock disappears when I run the motor without the serpentine belt. So this tells me I have a problem with one of the accessories (AC Compressor, Power Steering Pump, Water Pump, or Alternator), correct?

I've turned each of the accessories by hand and do not find anything unusual.

So I am wondering if anyone has had an occurrence of a knock when tension is put on the crank pulley. Would a bearing inside the engine only produce a knock if tension were put on the pulley?

Does a Harmonic Balancer produce a knock before it goes bad?

Thanks in advance for your help.

 

[91 HATCH]

it sounds like one of your accessories engine knock stays all the time and does not go away.

 

[DLFD911]

Have you tried putting your ear to a long screwdriver on the accessories while the knock is present? Might help pinpoint it. (don't try this on the balancer though )

 

[347strokin]

Automotive stethoscopes are cheap too, and can definitely help in pinpointing sounds.

 

[bretamo]

I put my ear to a heater hose to try to locate the knock, but I have not tried the screwdriver test.

Would a bearing inside the engine only produce a knock if tension were put on the pulley?

 

[5.0TailPipeHump]

Automotive stethoscopes are cheap too, and can definitely help in pinpointing sounds.

347stroker has the best idea by far by trying to locate an unusual sound , these autostethascopes are a good investment , i would try that route 1st .

 

[Fox8950]

If it were a bearing on the bottom end that was only knocking when you put tension on it the sound would be alot different than a rocker arm tick kind of sound or is that just the rhythm?

 

[bretamo]

The best way for me to answer that question is to say that it is more a "knock" than a ticking sound. No knock when I run the engine without the belt for a minute. It is sometimes has varying degrees of knock, most often more prevalent when warmed up than cold.

I'm getting a stethoscope this week for this. I like getting new tools.

 

[cjnecessary]

I had an a/c pump do that to me years ago it sounded like the car had all the rods getting ready to come out the pan. I sure do miss that dodge.

 

[bretamo]

Broken Aftermarket Underdrive Pulley

"What is a broken under drive pulley?"

That's what a paid mechanic said to me this morning. The MAC crank pulley is about a year old, and apparently cracked.

I can't believe I am paying a mechanic to replace it. A MARCH pulley is going on.

No more knock after I pay the bill tomorrow.

Thanks everyone for their help.

 

[302RollinHard]

At the end of this thread there is only one thing to say...........
SUCK IT TREBEC!