How do you determine the source of engine noise?
This is an update to “How do you know if you(r) C5 Z06 oil pump is bad?” posted on 12-16-15.

I replaced my stock LS6 oil pump on my 03 Z06 with a Melling 10296. Thanks to Bill Curlee, who helped me determine what was wrong with my stock oil pump. I didn’t want to install a new pump until I knew what was wrong with the original pump. The cause of the pump failure was the slider jamming in the open position.

I drove the car for 30 miles and the Melling pump produced much better pressure than the stock pump (55 psi at idle, and up to 80 psi at 3500 rpm). Then I changed the oil, which still had small pieces of babbet in it.

I changed the oil again and started the car again and a noise in the bottom of the engine had developed. How do you determine the source of engine noise?

I think my next step is to do what Bill mentioned he had to do with a friend’s engine, which was to remove the lower and upper oil pans and inspect the bottom of the engine – connecting rod bearings for damage/wear.

I bought a subscription to alldatadiy.com, but it does not have a procedure for removing the engine, or even inspecting or removing the crankshaft.

I found a post from 2003 giving 2 sources for a shop manual for $100. One source was Helm Inc. but the set of 3 manuals is now $300. Are there any other options? Maybe a less expensive digital version?

Also, I’d like to attach a video so you can hear what the noise sounds like, but I need to figure out how to shorten it because its 85 MB.
I would appreciate any advice regarding next steps and/or procedures for removing the forward cross member and inspecting/replacing bearings.

 

I just looked at your old thread and saw all the metal on the drain plug, looked very similar to mine when my oil pump went out. In my oil filter I found chunks of metal, ie large flakes and particulates in it, you can look at one of my threads I created where I took pics, if you saw flakes as large as mine you're going to need to pull the motor. Did you inspect cam and lifters for damage when you changed out your oil pump?

I don't think you're going to find a good way to inspect the bottom end without pulling the motor and dropping the pan. You should post a video.

 

Sent you a PM. Sorry about the motor.


Mr. Sam

 

I didn't have much metal in my oil or filter after the oil pump failed. Mainly small pieces of babbet. I did cut the filter open to examine it. Unfortunately I did not inspect the cam and lifters when I replaced the oil pump. Bill described a way to work on the bottom end without pulling the engine (you just have to remove the cross member) but I'd like more instructions before I attempt something like that on my own.

The video I took is too long/large in size. The only thing I could do is start the engine again and take a shorter video, and I'm not sure I want to do that. I'm hoping a mechanic friend of mine can come over this week and listen to it though, and when we start it I'll take a shorter video then and post it.

 

I'm also curious what caused the oil pump to fail in the first place. Yes, I was running the car hard on the track, but wasn't the Z06 designed to be a track car? I had fresh oil in it, and I had flushed/changed all the fluids prior to taking it to the track.

 

Technically, you could drop the front cradle if you have an engine hoist or something else holding up the motor. However, if you do in fact discover damage you will have to pull the motor anyway.

I believe if you pulled the intake manifold and used an engine plate and hoist you could support the motor. Then I believe all you would need to do is disconnect the shocks lower bolts, control arm upper bolts and keep track of the shims, disconnect brake sensors steering rack connections, engine mount nuts and cradle nuts.

 

In my case an unnoticed aluminum foil oil bottle seal fell in during an oil change and eventually got stuck in the oil pickup screen partially obstructing it. Then I assume during a WOT run it starved the pump for oil and damaged it. Lastly as the foil went through the heads it damaged a couple of rollers on the lifters, which them damaged the cam. Crappiest reason ever to pull a motor and rebuild the engine but was a great learning experience. Hope your situation isnot as grim as mine was.

 

I feel your pain. I had to pull my engine last year and rebuild it due to oil consumption and a severe leak. Here is a link to a article on how to pull your engine from the top. There are multiple pages in the link so you have to hit the next arrow at the bottom of each page. The article is a Z06 engine removal. This how I removed my LS1 from the top.

http://web.archive.org/web/201012091...engineswap.htm

I believe that if you metal in your oil and filter you will end up having to pull your motor for repair. Good luck with your repair.

 

To answer your question... I use an old broom handle about 2' long... put one end to your ear and place the other end on various parts and places on the engine... you will be surprised at ALL you can hear and pinpoint exactly where it's coming from by doing this method.

 

Thanks guys! I will dig into the info in greater detail after work!

It sounds like even if I think I can isolate the noise to the bottom of the engine... the smartest thing to do is pull the engine and inspect everything (instead of just replacing connecting rod bearings for example).

I really appreciate all the help and advice. If anyone else has additional references please keep them coming!

 

If you end up having to pull the motor here is a list of lessons learned from my experience. If you need a picture of something specific there is a strong chance I have picture of it. Let me know.

https://www.corvetteforum.com/forums...s-learned.html

 

I am reading though both links that you guys provided and it's really great info. It is giving me more confidence that I can tackle the job! I've enjoyed learning how to replace the oil pump and doing it myself! I think I'll take care of my clutch issue at the same time (at the track, when the car it hot, sometimes the clutch pedal will stay on the floor - it seems to also be when I'm near red-line that it happens) and just plan on having the car out of commission for the next several weeks. I have 7 kids, and I'm also involved in youth ministry at our church, so this type of work takes longer than I'd like, but I have to balance how I spend my time. I will keep posting updates, and a video of the noise (sometime this week).