I’m being told my engine is bad

[Michigan]

2004 Tahoe z71 4x4

175k miles

Owned it 1.5 years

Got it with 149,500 miles

Has had a minor leak since I got it (was lied to about no leaks)

I used Mobil 1 5w-30 full synthetic high mileage and changed oil religiously every 5k miles along with Mobil 1 m107 oil filter

Always kept an eye on oil level and topped off if needed. Maybe a quart or slightly more every oil change

Engine ran very strong the whole time of owning

Without any signs it has developed a clunking sound on startup. This all happened in the past two days. Actually I had the oil changed yesterday and coincidentally it got way louder after the oil change. Before the oil change I barely noticed anything and I wasn’t even suspecting anything really.

On cold start it is very loud. Clinking/rattling noise. I was told by 2 shops it’s the bottom of the engine. Both shops were confident that that’s what it is. Then there is a junkyard across from my work and it took it to him for a third opinion and he says he’s certain it’s the flywheel that’s cracked. I called one of the shops back and told the guy I’m not going against what he’s saying but I asked him the possibility of it being the flywheel. He said that’s the first thing they checked, he said they removed the cover and all the bolts or screws where there? Not sure exactly.

I tried posting a video through YouTube but for some reason it won’t download. It just keeps saying processing. I tried posting a video directly on here and it says file too large. I’ll try to figure out how to get a video clip soon. I know not much you guys can go by without a video and still hard to diagnose by video as it is but would like to got some opinions

Also is there anything else I should have replaced if I have them do the swap. Both shops are suggesting to get a used engine to throw one in.

First shop say he located one with 113k miles from a guy that they do business with regularly. He want to charge 2,500. Not sure about warranty with him but he said he’ll go through the whole engine before installing and replace any manifold bolts of broken, plugs and what not

second shop said between 2,000 and 2,500 not warranty and can’t promise leaks or anything.

 

[SnowDrifter]

A video would be quite helpful here. Youtube will process for a few minutes then you can post

 

[Kraig]

Clunking, knocking, rattling, or tapping? How’s your oil pressure now compared to what it was before this started?

 

[Big Mama]

More info needed and have you been under it to tell exactly where it’s coming from and is it only at start up? As for engines check powertrain products they have a nationwide warranty. I wouldn’t go with any engine you can’t verify leaks or strength.

 

[Michigan]

The video finally uploaded

Sorry not a great video. It was taken very quickly before work yesterday. I’ll try to get a better video and get the camera underneath the truck

Oil pressure has been fine. I think 40psi at idle and 60psi on the freeway.

 

[Michigan]

More info needed and have you been under it to tell exactly where it’s coming from and is it only at start up? As for engines check powertrain products they have a nationwide warranty. I wouldn’t go with any engine you can’t verify leaks or strength.

I was underneath it at the shop yesterday. Both shops said it’s lower engine. Coming from the pan?

The noise is there at startup. Very loud on cold start then settles down. When the engine is warmed up and I start it up it’s not too noticeable. Not much noise if any at all when idling but then if I rev it up the noise gets louder.

While taking off at slow speeds you can hear it but above 30 the noise is completely gone

 

[915_Tahoe]

one of my co-wokers says sounds like a flywheel. let me show this to a few technicians here at work and see what they think about it.

 

[Kraig]

What’s the puddle?

 

[Michigan]

What’s the puddle?

Puddle is just rain

one of my co-wokers says sounds like a flywheel. let me show this to a few technicians here at work and see what they think about it.

Appreciate the input. I still plan on taking it to one more shop to get a third opinion.

I’m not very knowledgeable when it comes to engines but If the engine was bad wouldn’t the sound be consistent when idling? Instead it settles down and the noise goes away

 

[Scottydoggs]

to rule out the flex, you take the three flexplate bolts to the torque converter, then fire it up. if its the flex the sound will be gone, if its still there its the engine.

does kinda sound like a flexplate. unless you broke a connecting rod, never heard a rod knock like that before, its more of a rhythmic banging sound.

 

[R3cord303]

That doesn't sound like bottom end damage at all. Bottom end damage will make it sound like an old clapped out diesel tractor.

 

[Big Mama]

The echoing of the pan does sound like a bottom end but most bottom ends sound like sticking something in a metal fan. The faster the fan the faster and louder the noise. If it is just the bottom half no need for a new engine just a short block. Did the 2 shops remove anything or just diagnose from below? I think this was asked is the oil level ok? Also on bottom problems the drain plug usually has metal shavings on it.

 

[Michigan]

The echoing of the pan does sound like a bottom end but most bottom ends sound like sticking something in a metal fan. The faster the fan the faster and louder the noise. If it is just the bottom half no need for a new engine just a short block. Did the 2 shops remove anything or just diagnose from below? I think this was asked is the oil level ok? Also on bottom problems the drain plug usually has metal shavings on it.

Oil level is fine

I wasn’t around for the diagnosis at the first shop but he claims he removed the cover for the flywheel to check that. I think they just went by sound and didn’t take anything else apart

Second shop I was there and they just lifted the truck up and just from the sound all three shop guys concluded it’s definitely the engine.

I know mechanical things do fail suddenly but would an engine that’s been running strong just develop this loud sound suddenly without warning? I.E wouldn’t it develop a small sound and gradually get louder and louder as time went by?

Like I said though the noise is not really there when idling but when revving the engine in park it consistently does get louder. I’ll have to another video as well as get in into a different shop

 

[Tonyrodz]

to rule out the flex, you take the three flexplate bolts to the torque converter, then fire it up. if its the flex the sound will be gone, if its still there its the engine.

does kinda sound like a flexplate. unless you broke a connecting rod, never heard a rod knock like that before, its more of a rhythmic banging sound.

Could you clarify a little on what you mean? To rule out the flex plate or not. Thx.

 

[Scottydoggs]

if you un bolt the tc from the flex, the engine wont be spinning the tc, you can also hit it with a hammer lightly, if it rings its still good, the flexplate that is. they dont ring if cracked. if it is broken, it should be silent or rattle way less unbolted.

once unbolted you might even get some play if you push and pull the flex. it should be tight and not move in any direction other then spinning round.

just recalled these dumb tranny dont have a open inspection cover. makes this job a bit harder for a inspection.

 

[ivin74]

Buy a 60 dollar inspection camara an look at the flex plate. That rules out the flexplate.

 

[iamdub]

The sound and symptoms really do sound like a cracked flex plate. You said the shop said they "removed the cover and all the bolts or screws where there". Yeah, you're not looking for loose or missing bolts. You're looking for cracks, either radial or concentric. They can be difficult to see through the small inspection hole and the at angle from which you're forced to inspect it. I'm with @Scottydoggs on this one. I'd unbolt the starter and use a large screwdriver or small pry bar to GENTLY pry the flex plate fore and aft. I say gently cuz you don't wanna bend it and make it a problem/an additional problem if it's not the problem.

 

[Jeff Groves]

That is a cracked flex plate. I have no doubt about that.
A bad bottom end does not sound like that.

 

[Michigan]

The sound and symptoms really do sound like a cracked flex plate. You said the shop said they "removed the cover and all the bolts or screws where there". Yeah, you're not looking for loose or missing bolts. You're looking for cracks, either radial or concentric. They can be difficult to see through the small inspection hole and the at angle from which you're forced to inspect it. I'm with @Scottydoggs on this one. I'd unbolt the starter and use a large screwdriver or small pry bar to GENTLY pry the flex plate fore and aft. I say gently cuz you don't wanna bend it and make it a problem/an additional problem if it's not the problem.

Edit I thought you guys were talking about flex pipe. Is flywheel and flex plate the same thing but just certain cars use one or he other? Like a timing belt bs a timing chain? Sorry. As you can see not my area of expertise


Thanks for the input everyone.

To answer your questions the shop said they first checked the flywheel. They said they removed the cover and checked for that and supposedly it was all good and yes even with the flywheel you’d still be correct they wouldn’t be looking for missing bolts or screws, they still be looking for a crack

Neither shop has made any mention of the flex pipe but before I created this thread I listened to a video with a bad flex pipe (can’t find it right now) and it sounded similar.

I don’t work on my cars and not very knowledgeable about the way the drivetrain and engine works but it’s always good to act like I do when taking it to a shop. So should I suggest the shop to check the flex pipe off rip or should I take it in again blind and tell them I’m hearing a noise without telling them other shops think it’s the engine or flywheel and also if I ask them to check the flex pipe they should be knowledgeable to check it without damaging it the way you describe right

 

[Jeff Groves]

You say Fly wheel. I say flex plate. LOL!
A Fly wheel is used on a standard transmission where you have the pressure plate.
Flex plate is used on an automatic transmission.
2 different chunks of steel.