'87 LeSabre - Knocking-type noise

[TrueLyFE]

I really don't know much about cars, and the person who does around here is pretty busy So I am just trying to figure out what this could be.

Two things - first, the subject. We (er, I should say the person who knows about cars) swapped out the old engine due to problems with another that was known good, with 78,000 miles. After putting it in it runs, but after a while a noise developed. There is a knocking-type noise that does not change depending on how fast the engine goes, but will almost completely go away after going into gear. I have no idea where this noise could be coming from or what it is... nothing seems to be moving anywhere, but then again, I really don't know what to look for.

Second - the fuse block diagram fell out and somehow got lost. Anyone know where to find another one / get a copy?

If you need audio of the noise, I can provide it.

Edit: http://true.damnserver.com/car-noise.mp3 is the sound.

[buickmastermind]

If the tranny has a lot of miles on it (above 140,000), then it may be developing a problem. Check the fluid to make sure there is enough in it, or if it has any odors or metal flakes. Also, check to make sure the Trannsmissions' vacumn modulator is connected to the engine vacumn. It is located on the front drivers side of the tranny, and has a hose that goes to the vacumn bay on the throttle.

Try to see if you can locate where under the hood the noise seems to be coming from.

I can get a copy of the fuse block cheat sheet off my car, as they should be the same. I'll post it here as soon as I can.

[TrueLyFE]

Regarding the transmission, that was recently flushed and the gasket was replaced on the pan; fluid is fine and during testing after putting in the new engine, it drove great. I will have that connector looked at (rough guess tells me that it is already hooked up, especially if it is a hose as every hose was almost definately reconnected, but I will check just in case). Keep in mind this noise is while in park and the idle is a little high - when going into drive (RPMs drop down) the noise goes away until RPMs go back up, then the noise returns.

It is hard to say where the noise is, because it is so loud. I should probably record it so you have an idea of what it sounds like. It starts up right when the engine starts up. I'll try to get it recorded tomorrow after work, depending on if I can remember or not.

And regarding the fuseblock diagram: thanks in advance!

[TrueLyFE]

Here is the audio that I finally recorded of the noise. The noise went away when shifting into reverse, and started coming back near the end when it was back in park and being shut off. As I said before, the repetitions in the noise do not change if I rev up the engine.

http://true.damnserver.com/car-noise.mp3

Thanks

[buickmastermind]

Okay. Sorry it took so long to reply.

That noise can only be one of two things. Either the timing chain jumped, or the bearing(s) went bad. Most likely a rod bearing. That is why it is so loud. The reason it quiets down in gear is there is a load on it.

[TrueLyFE]

But the noise comes back when speeding up...

That is something that another person suggested - I will let the person who actually put the engine in know, and they can probably repair it. Thanks.

[buickmastermind]

Here is that fuse block detail sheet:

http://files.automotiveforums.com/ga...hp?photo=40871

The Last one is hard to read, but it is a 5 amp fuse for the instrument panel lamps.

[TrueLyFE]

Thanks. Wish it was higher resolution and without the watermark, but I guess I can't complain. I did lose mine mysteriously anyway to begin with....

Had the house mechanic drain the oil and pull off the oil pan, and (I guess luckily since you were correct on diagnosis) she found the damaged rod bearing. Hopefully after replacing that tomorrow, it'll be great to go

Thanks yet again..

[buickmastermind]

If you need any advice about changing the bearing(s) just ask.

Good luck!

[TrueLyFE]

She should have it covered, but if she runs into anything, I'll post

[Steven Geraurd]

I have the same car, possibly same problem. Check your harmonic balancer (crankshaft pully) to see if it has separated. Mine is a steel with rubber dampener that separated and started to hit a piece on the engine block, making a ratcheting sound, mainly at idle. I used a Chiltons manual to help in the process. Chisel off the heads of the plastic retainers for the splash guard (passenger side, behind the wheel you'll have to remove. I had to use a puller to get mine off.

[TrueLyFE]

Replacing the bearing solved the issue. More than one may have been affected though as the noise is still there, but it isn't nearly as loud and goes away most of the time (aunt thinks it is probably another one going out). So we'll see as time goes

[buickmastermind]

Use a heavier oil. It'll help keep the bearing from going as fast.

[TrueLyFE]

Thanks. I'll let her know for its next oil change.