Something internal broke!

[hotwhip9]

After driving around for a few hourse yesterday doing some shopping with a friend, going store to store putting on roughly 50 miles or so it started pouring out. I noticed a small knocking noise and and so I checked the oil level and it was a little low, so I added half a quart. The noise as I had to get home and babied it the whole way got worse. This morning I went out checked the oil again, and it was low. Added 2 quarts. Have Mobil 1 synthetic in it, and thats what I added, last oil change 3500 miles ago. The noise is not constant and it seems to start off loud and sometimes get quiter. My roomate suggested that it may be a lifter that is stuck. The noise like I said is not a constant tick but more of a clunk, definitely 2 pieces of metal hitting together somewheres. I was also thinking it could be water in the intake that may be causing this but that would explain a knock, not a clunk. Anyways inside the ram air hood there was a small amount of moisture before it goes into the airbox. That's about all the info that I can think of right now, so where do I start? I don't really trust any shops around here and even if it takes me forever, I trust my self over a shady mechanic near a military base. Any tips/ pointers similary problems and fixes are greatly needed. Until then my baby sits parked and lonely.

[Joe 1320]

This is going to be a tough diagnosis. Generally a lifter is going to generate noise that increases with fequency of RPM, but not as a result of higher load. Crank and rod bearings will increase in amplitude with higher load. What that means is with a lifter, as the revs climb, the noise gets more frequent. With the lower end, the higher rpms will increase the frequency, but they get louder with additional load (throttle in gear). The first thing to do is pull the belt and make sure that the knock is not from an accessory. A mechanic's stethescope should be used to pinpoint the noise. If the lower end is suspected, you can pull the oil pan and check the clearances of all the bearings using plastigage. One common backyark trick is if the lower end is suspect, you can remove a spark plug wire from the suspect cylinder to eliminate the combustion event. If the bearing noise dissappears, you know that bearing has too much clearance. I feel for ya, knock is not good. On a side note, lower end noises are generally lower pitched like a clunk rather than a click.

[hotwhip9]

Thanks for the advice and some more info on it, it idles fine, the oil pressure is normal, and increase in rpms makes no difference to the noise. I'll try what has been suggested and go from there and see what happens. Thanx joe. Also, how much clearance should i have on the bearings? Doesn't plastigage come in different sizes?

[hotwhip9]

could be power steering

After removing the serpentine belt i wiggled the pulleys and found what seems to be part of the noise in the powersteering pump. I'm going to get a stethescope tomorrow and hopefully determine if that is all the noise. Could the be the problem or just another one? Would it make that much noise, its hard to tell exactly where its coming from because it is so loud. Power steering pump replacement on the LS1 not to hard?

[Joe 1320]

The pump could be the culprit, did you run the engine with the belt off to make sure?

Plastigauge comes as a kit. It is basically a waxed string that is placed on the bearing surface and the bearing is torqued into place. The wax spreads out , you disassemble and measure how wide it spreads and compare to the included chart. Pretty cool stuff. I don't have the specs on an LS1, I would suspect they would be the same as an LT1....
*rod bearing clearance .0008 to .0022
*rod side play .003 to .015
*main bearing clearance .001 to .003
*crankshaft end play .002 to .008
hope this helps

[JL8Jeff]

I thought there was some kind of known oil pump problem on 98 and 99 LS1 engines. I know you said your oil pressure is fine, but the fact that you had to suddenly add that much oil isn't a good sign. It sounds like you could have some bearing damage at this point. Take it to the dealer and let them listen to it, it could be something that is covered under warranty or is a recall or TSB.

[Joe 1320]

I agree..... having to add that much oil is not good.