Two LT1 noises on video. Bad lifter, bad cam lobe or rod?

[woodstockdrift]

Hope you guys are doing good. I'm new to the C4 and don't know exactly how a LT1 should sound so here are noises that worry me. There are 2 noises, 1 video for each


FIRST a "wob wob wob" Took the video at about 150 F just a few minutes after starting up.


93 C4 LT1 sounds - 150F - YouTube


SECOND is like a fast "tih-tih-tih" and first noise is gone from what I can tell. I took it after a 10 to 12 minute drive


93 C3 LT1 Sounds - 205F - YouTube


I spent 2 hours straight searching threads but I'm not sure how to narrow it down. I think the first noise might be an exhaust leak. The second noise worries me more. It could be dirty oil, bad lifters, dirty or bad injectors, bad cam lobe even a bent rod?? The oil was changed 500 miles ago 5W30 synthetic. Don't think the car used synthetic before, don't know if that matters. Engine performance is good, start up is good.


The second noise seems to be coming from where I mostly had the camera. I just learned how to change brakes and I also just learned what a lifter is :eyerole so I will end up taking it to a shop but Im hoping you guys can help me understand this potential problem better. I am learning as much about the C4 as I can and want to take very good car of this car.

 

[DonB]

Well here goes. The first noise could be a few things, the wop,...wop,...wop, sounds a lot like a bad A.I.R. pump. When mine failed, it was popping out the back of the pump. To check this,.. Briefly take the belt off and run the engine(so the pump doesn't turn). If the noise goes away, Viola! You will also be able to feel some air being expelled from a small 3/8" hole in the back of the AIR pump. Replace the AIR pump.

It also could sound like you may have a single exhaust port leak. Like the gasket is ruptured slightly at one cylinder exhaust port to the manifold. I'd also check for an EGR tube leak(if equipped.) Either way,..It is definitely air being pushed out of somewhere!


The second noise, sounds like valve train noise. More than likely it could be a slightly loose rocker or a sticky lifter. Before I got all crazy here's what I would try. Lifters have a tiny hole in them so they can be hydraulically "charged" by engine oil and creating a cushioning effect for the valve train. They have been known to get the small oil hole it them varnished up(clogged) after years of use and that causes the lifter to NOT hydraulically pump up all the way. This causes a small amount of "play" or slop in that valve mechanism; Thus the ticking noise.

Add about a half a quart of ATF or Marvel Mystery Oil to the engine oil. Run it for a hundred miles. Don't worry an extra half quart of oil won't hurt anything. But, If you are REAL concerned about oil level, drain off up to a quart of motor oil first and replace it with ATF(or M.M.O.) You see ATF is just a highly detergent 10 weight oil. That's why the inside of automatic transmissions are always so clean.

Be sure to change the motor oil and filter after a hundred miles(or when the ticking stops). NOTE: The ATF WILL break loose a lot of other crud if there is a build up in the engine too. So don't leave it in there for too long.

Then at least, if the ticking has NOT subsided, THEN you know it's time to pull the valve covers for a valve train inspection and probably adjust the valves. You should then change the oil anyway.

Good Luck. Let me know how you make out.

 

[woodstockdrift]

Well here goes. The first noise could be a few things, the wop,...wop,...wop, sounds a lot like a bad A.I.R. pump. When mine failed, it was popping out the back of the pump. To check this,.. Briefly take the belt off and run the engine(so the pump doesn't turn). If the noise goes away, Viola! You will also be able to feel some air being expelled from a small 3/8" hole in the back of the AIR pump. Replace the AIR pump.

It also could sound like you may have a single exhaust port leak. Like the gasket is ruptured slightly at one cylinder exhaust port to the manifold. I'd also check for an EGR tube leak(if equipped.) Either way,..It is definitely air being pushed out of somewhere!


The second noise, sounds like valve train noise. More than likely it could be a slightly loose rocker or a sticky lifter. Before I got all crazy here's what I would try. Lifters have a tiny hole in them so they can be hydraulically "charged" by engine oil and creating a cushioning effect for the valve train. They have been known to get the small oil hole it them varnished up(clogged) after years of use and that causes the lifter to NOT hydraulically pump up all the way. This causes a small amount of "play" or slop in that valve mechanism; Thus the ticking noise.

Add about a half a quart of ATF or Marvel Mystery Oil to the engine oil. Run it for a hundred miles. Don't worry an extra half quart of oil won't hurt anything. But, If you are REAL concerned about oil level, drain off up to a quart of motor oil first and replace it with ATF(or M.M.O.) You see ATF is just a highly detergent 10 weight oil. That's why the inside of automatic transmissions are always so clean.

Be sure to change the motor oil and filter after a hundred miles(or when the ticking stops). NOTE: The ATF WILL break loose a lot of other crud if there is a build up in the engine too. So don't leave it in there for too long.

Then at least, if the ticking has NOT subsided, THEN you know it's time to pull the valve covers for a valve train inspection and probably adjust the valves. You should then change the oil anyway.

Good Luck. Let me know how you make out.

Thanks Don! I'm going to tackle the second noise FIRST.

I used a mechanics stethoscope on the bolts on the valvetrain since that's what gave me the most consistent sounds. Anywhere else sounded very different even 1 cm apart. The bolt on the driver side that is closest to the windshield sounds different from the others but not by much. The rest sound like a mix of shaking, slashing or whirling sounds. That one bolt makes those noises but it has a light tick to it thats ticking at the same pace as the general "tick" you hear.


I did another video where you can hear the sound getting a little louder as the camera moves to the valvetrain.


LT1 2nd sound - 215F - YouTube


What should I do next? I was told on another forum that it wouldn't be a good idea to do the additives or oil changes and run the car if is a bad lifter or cam lobe. That was my worry. Is there a way I can check without having the whole engine taken apart? I saw someone in a video pull lifters with a magnet but it was a different Chevy engine. Oil changed about 500 to 1000 miles ago with about 105 k. Will figure out the brand but it went from 5W30 to 5W30S.


Will a scanner or laptop scanning software help?

 

[DonB]

A scanner will NOT help for "hard" engine noises

The ATF is a proven solution. I've been wrenching since late 60's. I used to be a dealer mechanic. Just be sure to change it after a short period as I instructed.

Of course you can do as you wish.

 

[kpic]

What should I do next? I was told on another forum that it wouldn't be a good idea to do the additives or oil changes and run the car if is a bad lifter or cam lobe.

woodstockdrift
What I would do is listen to DonB. Some ATF followed by oil change is a cheap date.

CAC has quite a few Master Techs, real mechanics and sorry guys , even some stealer-ship mechanics.

(IYes, I know 'll pay for that comment... )

 

[DonB]

woodstockdrift
What I would do is listen to DonB. Some ATF followed by oil change is a cheap date.

CAC has quite a few Master Techs, real mechanics and sorry guys , even some stealer-ship mechanics.

(IYes, I know 'll pay for that comment... )

Stealer-ship... kpic? REALLY? Well I NEVER!,...(laughed so hard.) Good one.

Furthermore, in relation to the O/P,.. Your engine is running too smooth to have a flat cam. If you did, at least one cylinder would be under-powered and the engine would be missing and shaking. Engine vacuum would also be low. If you are pulling around 18" or better and the gauge is NOT severely pulsating, you are OK. Flat cams were an issue in the late sixties and seventies. I haven't heard much of it lately.
But let's be the "Devils' Advocate here." Remove the oil filter and cut it open. If you had a hard part failure, the oil filter will be full of metal particles as will the bottom of the oil pan.


ATF is a detergent, NOT an "additive." Additives are capable of gumming up engine components, but more than anything "we" call them "Snake Oil." They don't accomplish much of anything but ending up at the bottom of the oil pan and emptying your wallet. Quality, clean oil is the best remedy.

 

[bobmo]

Since we are on the topic of stuff in our oil pans.
What's your collective take on Seafoam.
I've used it for years on my olde Mazda PU and am surprised how clean the internal parts are after 244k miles.
I dump a can in the oil about 500 miles before an oil change. And once a year down the Carb.
Bobmo

 

[DonB]

Seafoam is great stuff. I've used it in my boats fuel system in the spring for years. I put Sta-bil in prior to winter storage as well as fresh engine oil & filter. I've never actually used it in a car because I change the oil at a max. of 2500 miles. I normally use Chevron fuel system cleaner/conditioner twice a year in my cars.
Though last winter I put a whole new fuel system in my Vette because the tank was getting bad. New tank, lines, pump, reg., injectors & resealed the rail. Quite a project.

 

[kpic]

Seafoam is great stuff. I've used it in my boats fuel system in the spring for years.

Same here, I used it my boat engines for years also. The first time, my 18' with a 150 Merc laid out a smoke screen the US Navy would be proud of..

 

[DonB]

Same here, I used it my boat engines for years also. The first time, my 18' with a 150 Merc laid out a smoke screen the US Navy would be proud of..

What a coincidence! My previous boat was an 18' Mach1 with a 150 Black Max Merc. V-6, 2 Stroke with oil injection. Gosh that boat was quick! I miss it.

And yes at times the Merc. was great for "Mosquito control!" Especially the first start-up in the spring to burn out the fogging oil......I think my neighbors were ready to call 911. LOL!

 

[woodstockdrift]

Well here goes. The first noise could be a few things, the wop,...wop,...wop, sounds a lot like a bad A.I.R. pump. When mine failed, it was popping out the back of the pump. To check this,.. Briefly take the belt off and run the engine(so the pump doesn't turn). If the noise goes away, Viola! You will also be able to feel some air being expelled from a small 3/8" hole in the back of the AIR pump. Replace the AIR pump.

It also could sound like you may have a single exhaust port leak. Like the gasket is ruptured slightly at one cylinder exhaust port to the manifold. I'd also check for an EGR tube leak(if equipped.) Either way,..It is definitely air being pushed out of somewhere!


The second noise, sounds like valve train noise. More than likely it could be a slightly loose rocker or a sticky lifter. Before I got all crazy here's what I would try. Lifters have a tiny hole in them so they can be hydraulically "charged" by engine oil and creating a cushioning effect for the valve train. They have been known to get the small oil hole it them varnished up(clogged) after years of use and that causes the lifter to NOT hydraulically pump up all the way. This causes a small amount of "play" or slop in that valve mechanism; Thus the ticking noise.

Add about a half a quart of ATF or Marvel Mystery Oil to the engine oil. Run it for a hundred miles. Don't worry an extra half quart of oil won't hurt anything. But, If you are REAL concerned about oil level, drain off up to a quart of motor oil first and replace it with ATF(or M.M.O.) You see ATF is just a highly detergent 10 weight oil. That's why the inside of automatic transmissions are always so clean.

Be sure to change the motor oil and filter after a hundred miles(or when the ticking stops). NOTE: The ATF WILL break loose a lot of other crud if there is a build up in the engine too. So don't leave it in there for too long.

Then at least, if the ticking has NOT subsided, THEN you know it's time to pull the valve covers for a valve train inspection and probably adjust the valves. You should then change the oil anyway.

Good Luck. Let me know how you make out.

Hi DonB. I was not able to do anything with the car until recently. Thank you, your advice is the most thorough Ive received on any forum. I added half a quart of MMO like you said and ran the car 100 miles and I'm still getting the lifter noise. Here is the original video to remind you of the "tick tick tick":

93 C4 LT1 Sounds - 205F - YouTube


I can't say if it got louder or quieter after the MMO. BEFORE running with MMO I pumped some oil out through the dipstick because I was a little worried about having too much oil and this is what it looks like:



click on them for a much larger pic



This oil is before the MMO was running. Doesn't that seem pretty dirty to you after just 500 miles? That's when the last oil change was done. Luckily I did not see any metal flakes while moving the oil around or any at the bottom of the bottle after it sat for a couple days.

So is the next move trying another half quart of MMO?
OR
Removing the valve covers to see if its a rocker that needs adjusting? How would I be able to tell if a rocker needs adjusting?

I think the step after examining the valve covers is pulling the lifter rods to see if they're bent and also inspecting the lifters. Thats something I'd have a mechanic do so dont worry I wont ask you to guide me there haha

I did do the stethoscope thing like I wrote earlier and I think the noise is coming from a corner of the valve train on the driver side.One new thing I noticed is that the ticking noise gets faster with RMPs rising and then goes away if they go past like 1,500. Thanks for the help!

 

[DonB]

HiDon

How's it going wsd?

 

[woodstockdrift]

How's it going wsd?

Hi haha I hit Submit Reply before I wrote the rest of my post. My update is right up above, appreciate the help!

 

[DonB]

Hi woodstockdrift. I was just able to read your post. To answer your question(s), I'd put some more M.M.O. in it and run it till the next oil change. You have nothing to loose and it won't hurt anything. Here's my reasoning: 1.) Your ticking ISN'T real bad. Heck, many, many engines tick a little at idle because oil pressure is low at idle with most stock oil pumps. I've heard some that sound like a "popcorn machine." You said the noise goes away after 1500 RPM. That's just a little touch of the throttle. So don't get all wierded out over this. It's minor.
2.) If you REALLY have to address it NOW, I'd pull the covers and inspect it. Grab each rocker and see if any are loose and can be moved by hand or try to twist the pushrod. Pay particular attention to the ones in the area where you defined the noise. If you find a loose one,..Viola!
3.) Wether you or your mechanic adjusts the valves, I'd BE SURE to use a set of "Rocker-Stoppers," on the rockers arms while adjusting, to prevent HOT oil from being thrown all over the place. Lisle Tool Co. makes a set #35500 that is on Amazon for like $11.50 Amazon.com: Lisle 35500 Rocker Stopper: Automotive Great little invention those Rocker-stoppers!
4.) If you think you want to try it, I could explain how to do it, correctly. You'll need a vacuum gauge too. It isn't hard. JUST a bit MESSY! but if not, I understand. Here's a picture of mine with the rocker-stoppers on it, before I started the adjustment procedure.
Note: My stoppers are antiques. The new type are a bit different, but you'll get the idea.


Keep me posted and let me know how you make out. Don

 

[woodstockdrift]

Hi woodstockdrift. I was just able to read your post. To answer your question(s), I'd put some more M.M.O. in it and run it till the next oil change. You have nothing to loose and it won't hurt anything. Here's my reasoning: 1.) Your ticking ISN'T real bad. Heck, many, many engines tick a little at idle because oil pressure is low at idle with most stock oil pumps. I've heard some that sound like a "popcorn machine." You said the noise goes away after 1500 RPM. That's just a little touch of the throttle. So don't get all wierded out over this. It's minor.
2.) If you REALLY have to address it NOW, I'd pull the covers and inspect it. Grab each rocker and see if any are loose and can be moved by hand or try to twist the pushrod. Pay particular attention to the ones in the area where you defined the noise. If you find a loose one,..Viola!
3.) Wether you or your mechanic adjusts the valves, I'd BE SURE to use a set of "Rocker-Stoppers," on the rockers arms while adjusting, to prevent HOT oil from being thrown all over the place. Lisle Tool Co. makes a set #35500 that is on Amazon for like $11.50 Amazon.com: Lisle 35500 Rocker Stopper: Automotive Great little invention those Rocker-stoppers!
4.) If you think you want to try it, I could explain how to do it, correctly. You'll need a vacuum gauge too. It isn't hard. JUST a bit MESSY! but if not, I understand. Here's a picture of mine with the rocker-stoppers on it, before I started the adjustment procedure.
Note: My stoppers are antiques. The new type are a bit different, but you'll get the idea.
View attachment 23911View attachment 23912

Keep me posted and let me know how you make out. Don

I really appreciate the help Don. I am new to diagnosing cars issues so Im glad there's very helpful people online like yourself!

I cut open the oil filter and looked for any metal particles as a way to check for hard part failure like bearings. I know the oil I posted pictures of above looked fine but this C4 is my pride and joy so I wanted to be really sure. The filter looked fine and replaced it with a better one - K&N. I added some more MMO and will run the car a little more and then go with the valve cover removal.

What are the chances its an exhaust manifold leak? I ask because I hear the tick from the bottom of the car near the tire. its louder than near the valvetrain.

BTW You are right about the ticking noise, its not bad. Hell I found out some people never take of it haha I just got scared after reading all the possibilities when I first started researching this. Thanks again

 

[Mixalive]

Well here goes. The first noise could be a few things, the wop,...wop,...wop, sounds a lot like a bad A.I.R. pump. When mine failed, it was popping out the back of the pump. To check this,.. Briefly take the belt off and run the engine(so the pump doesn't turn). If the noise goes away, Viola! You will also be able to feel some air being expelled from a small 3/8" hole in the back of the AIR pump. Replace the AIR pump.

Guys, I am new to your forum so I don't want to be all corrective. But I have some experience with the AIR pump on my 92 LT1. If the OP's 93 LT1 is like mine, you have an electric AIR pump behind the driver side front signal lights. So it is not belt driven. If you think the noise is coming from the AIR pump, you can just disconnect from the system. But disconnect it at the pumps motor. Do not disconnect the pumps relay as the relay lets the ECM know that it is there. Basically, you will throw a SES code if the ECM does not see it. There is a fuse at the motor you can pull to make things simple. I removed mine all together as Texas doesn't require emissions test after 25 years old.
If you think you have a stuck lifter, that Mystery Oil tip is a great idea. I use that stuff for these type of purposes all the time. But looking at this thread, I didn't see noted the type of oil you are using. I hope you are using full synthetic as recommended in your owners manual. I have 145K on my LT1 and runs like a top.

 

[pschaef1]

Two LT1 Noises on video

Was the source of the "wop-wop-wop" ever discovered? I ask because I have exactly the same sound on my 96 at startup until the engines warms up.

 

[Hib Halverson]

Well here goes. The first noise could be a few things, the wop,...wop,...wop, sounds a lot like a bad A.I.R. pump.

(snip)

Only thing is...a 93 LT1 doesn't have an engine-drive AIR pump. On a '93 the AIR pump is electric, not mounted on the engine and only runs for a short period after start-up. When they a failing, they don't make a "wop, wop, wop" noise they usually squeal or, once they've failed, they don't make any noise at all.

On the first noise. I'd get the car up in the air on a hoist or jack stands. Fire the motor then get under it and see of you hear the noise louder from the oil pan.

Do you?

As for the second noise...without knowing how you recorded the sound track, it sounds to me like all the lifters or rockers are making noise.

What's the engine's hot oil pressure at idle and at 3000 rpm?

Before you get crazy with "Marvel Mystery Oil" and "Sea Foam" know that Mystery Oil is a very strong solvent and thins oil. I've never advocated using the stuff because of that, however, pull off a valve cover and take a look. If you don't see sludge and a lot of evidence of dirty oil, Marvel Mystery Oil won't help.

As for "Sea Foam", one of the best marketed BS pour-in additives there is, it's mostly a "top engine" product for fuel systems and combustion chambers not dirty valve lifters.

Lastly, if you have an engine mechanical problem so bad that all the lifters are making noise, my guess is there are no pour-in solutions. You need to fix the freakin' motor.