Well Saturday my car lost coolant from the water inlet pipe popping off of the water pump. The car overheated VERY quickly but I managed to park the car within about 10 minutes of first noticing the engine overheating.

Here's my current problem. Before turning the car off, I could have sworn I heard a knocking noise which sounded awfully like when I spun a rod bearing in my Mustang. The car was flat-bedded to my mechanic's shop afterwards and not started. Well we've since managed to "band-aid" the pipe so it stays on the water pump securely. This is only temporary, we just wanted to verify the engine noise.

We filled the car up with coolant and started it up, blasted the heater and proceeded to "burp" the system. Here's the thing, the knocking noise seems to have vanished. We let the car idle for about 20 minutes, confirmed it is not overheating at all, and then we started to rev the car slowly and gradually rising in RPM. No matter what we did there was no knocking or unusual sounds at all. We proceeded to do this for about 45 minutes...nothing.

So, my question is, is a spun rod bearing or crank bearing something that can be noisy intermittently? Does anyone else have a possible explanation for the noise (i.e. something else internal)? Should I go ahead and drop the oil pan to check the bearings? I don't know if it makes any difference, but I have an AMS 2.3 stroker bottom end..

Thanks folks

 

Possible detonation (knocking) from excessive heat.

 

sounds like you were just knocking...as long as you did'nt leave it like that...

 

Thanks for the help, I didn't think about that. Does detonation sound similar to a spun bearing? It was fairly faint..but loud enough to hear with the windows down.

I definitely did not have the car running long in that condition. I'd say from the instant I heard the knocking noise it was off within 10 seconds.

 

I have heard many different types of knock, form faint to really loud. It's usually audible though if that's what you're asking. Look it up on youtube or any video site, there are many videos that show and/or let you hear the familiar knocking noise.

 

Oh no, what I meant was does detonation sound similar to what a spun bearing would sound like, the noise was definitely audible. I've been looking on youtube but it seems it's pretty difficult to get detonation on camera lol (most vids are of rod-knock or spun bearings, lifter tick, etc.)

thanks!

 

A spun bearing should have a rythmic sound when knocking. Detonation would sound different and would not be constant.

This is my expereince with the motors that I have blown up.

 

knocking sounds like sex sounds of a man and a women
spun rod soudns like sex sounds of 2 gay men.

 

edit

 

^ LOL!

Pop the hood while its idling, and rev it up and down using the throttle cable. If its something internal, you'll hear the noise get more frequent as the RPM's rise, and less frequent as they drop.

 

Do a compression test and compare to former values. Even if the compression is fine the gasket may have weakened from heat and may go some time in the future.

Was the knocking sound a detonating noise or journal resonance?

If it was journal noise it is easy to pull the pan and check everything, replace and gauge rod bearing clearances. If everything is fine there then likely the main and balance bearings/journals are good too.

However, most of the temperature probably soaked the head since the oil squirters kept the pistons and rings cool. If it were me I would probably have the head pulled and taken to a machinist.

With all said there is a chance nothing was damaged at all so it basically depends on the route you take checking everything. Thouroghly think out everything before taking action