For the Vehicle Mechanics

[sasquatch]

I have a 2006 Silverado, 4.8 engine. 145k miles

Bought it 1.5 years ago in good physical condition. No oil leaks, runs good, clean etc etc

Now it starts tapping pretty hard, never goes away. Take it to one shop and they basically say just let it tap until it breaks

Bring it to dealership and they say it’s likely cam issue. Would be 1100 just to open it up, they recommend just replacing the engine

I take it to another mom and pop shop after that. They tell me it’s cam issues, and also recommend just replacing the engine.

Does this sound right, better/easier to replace a whole motor? The mom and pop wants $5k to do so plus any bad parts found when tearing apart such as say a water pump.

I can’t sell it like it is really, so I’d have to just lose the money I have in it. I think I’d spend a good bit more to find a decent used one again low miles etc etc

Idk what to do. Suggestions?

 

[tony]

Does the tap speed up or get louder when you give it gas?
I had a 99 f150 that tapped and got worse when driving. Ended up being a rotten out exhaust manifold.
Friend of a friend fixed it for like $600.00.

 

[Machingeaneer]

The reason they're telling you it's likely better to replace/rebuild the engine because if something did let go in the valve-train it is continuously sending metal shavings through your oil which is very hard on the bearings throughout the rest of the engine.

One option you may have is to find a used engine for the truck. They made millions of 4.8l and 5.3l V8s from 1999 - 2007 that will drop right in to your truck with minimal difficulty for a competent mechanic. You can probably find a low mileage example for around $1000 and potentially come out ahead vs. a full R&R or reman replacement.

One diagnosis suggestion would be to check all of the pulleys your serpentine belt rides on. If one of those bearings fail it can make some awful noises.

 

[Honfor500]

Try to find a good mechanic you can trust or self diagnos from YouTube videos

 

[sasquatch]

The noise don’t get louder really as I speed up but I can hear it at any speed

At done it’s almost a clink sound from the lower part of motor on drivers side

The last I brought it seems to be pretty reputable from the local area/reviews

The metal shavings concern was exactly what they mentioned as why I should replace the engine over repair what’s there

Sent from my iPhone using Tapatalk Pro

 

[dieselchessy]

A reman long block is in the $3k range, then a few hundred for consumables and $1.5k for labor sounds about right.

To tear it down to see whats the issue and then decide to replace might double your labor cost.

145k seems low, but no idea if folks have kept up on oil changes or overheated the thing.

 

[Silveroddo]

I haven't heard of it in the 4.8's, but there was a run of 5.3's in that generation that had wrist pin issues. I had one in a suburban, started ticking, ran fine, but there was a constant tick. At first I thought it was a lifter and went through all the youtube stuff to no avail. I sold it to a buddy as is and he drove it quite awhile. He tried putting a heavier oil in it to quiet it down (They strongly urge not to do that with those motors) It didn't change anything, the truck lived in a heated garage, one night he had to leave it outside for some reason, cold started it the next morning at -20 and the wrist pin finally failed and we figured out that it was in deed the wrist pin.
The 4.8 is a great motor, but things happen, it could be valve train related.
The mechanics you're talking to are giving you the best advice they can, they could diagnose it and go through the motions further but it will just add to the cost.
It wouldn't hurt to check around a little more. We have a local guy that's Rain man when it comes to those trucks. Does it throw any codes/check engine lights? It likely doesn't matter, but if its a cam issue I would almost think someone could tell you what cylinder number it's affecting, which would verify the cam issue I would think. I would be in the run it till it fails camp unless I had a really solid diagnosis that let me know it was on its last legs.
Regardless I wouldn't hesitate to throw a motor in that truck and keep driving it. I had an '03 with that drivetrain that I sold at 260K that was all original and ran great and I've got another one at 225k that I have no plans of retiring anytime soon.

 

[Westernduck]

From reading your post, I’d agree with the shops. From a business standpoint, it’s cheaper to replace it with a new one that would be warrantied by someone else, vs paying a tech to tear it apart and potentially not find the source. If you like the truck I’d say it’s a reasonable price.

 

[GotDraw?]

Send a sample of your engine oil out for analysis from NAPA, the will sell you a kit with a sample jar to mail. That test will tell you if you have bearing wear, ring wear, oil contamination, etc.

This is what airlines do, it is very accurate.

Be sure to take the sample with the engine warmed up. Follow the instructions and give them the number of miles on that oil (i.e. 4,500 miles since last change)! Do not change the oil before testing it.

JL

 

[SDHNTR]

Agreed. Not worth just replacing a top end. Just be prepared for the auto tranny to go next if it hasn’t been rebuilt already. If you like the truck, spend the money to fix it right. If not, spend the minimum amount (used engine) to get it back up and running and sell it and go buy another used truck with more life in it.

 

[cnelk]

For ~$25, get a can of BG109 EPR.
Put it in the crankcase and run the motor @2000rmp for 20-30 mins.

Change the oil /filter and see if that helps.

 

[Hoghead]

Most likely cam or lifter issue I have seen it a lot. The cost of repair wouldn't be far off from a used engine.

 

[Jbehredt]

Could be a worn cam lobe. A stuck lifter. Low oil pressure. Exhaust manifold should be looked at very closely. Especially since you say it’s more prevalent lower on the one side.

 

[isItFallYet]

I wouldn’t be afraid to buy any 1st or 2nd gen LS 4.8, 5.3, or 6.0 with less than 200k miles and swap it in there. Also, I think working on any chevy small block is really a doable for a shade tree mechanic.

If it were me, I’d pull it myself and fix whatever is wrong with it. Id be willing to bet that the pistons, rods, bearings are all still sitting pretty.

 

[HiMtnHntr]

Ran into this with ford 5.4 3v. Had cam job done instead of total rebuild or replacement. There’s no 100% way they can tell you your engine is salvageable until they look at the damaged parts and whether or not they got down in the motor. Try to find a shop that specializes in rebuilds.

 

[TaperPin]

More than one engine replacement has been sold when an exhaust leak sounds like a tap - like jbehredt said.

Many shops use a loud tick as a money bell - easy to sell new engines when it happens. Personally, I can’t imagine calling an engine toast without at least pulling the valve covers. This is an older design - no overhead cams, or whatnot. Even pulling a head is doable relatively quickly if there is a valve issue.

I’d find someone to actually diagnose the issue, rather than guess, but it isn’t free so there’s a risk it’s money down the tube. The new generation of automotive bore scopes placed in spark plug holes can quickly tell if all the valves are seating and not hanging up or bent.

If you like the truck it does have enough miles to make a new engine an easy call if you can afford it. If a new engine costs $5k and lasts another 150k miles that’s way cheaper than any new vehicle. If it turns out to be a stuck valve and the cost is more than $1,500 to redo the heads and get another 50k out of the engine, the cost of repair per mile favors the engine replacement or rebuild.

 

[mtnbound]

The noise don’t get louder really as I speed up but I can hear it at any speed

At done it’s almost a clink sound from the lower part of motor on drivers side

The last I brought it seems to be pretty reputable from the local area/reviews

The metal shavings concern was exactly what they mentioned as why I should replace the engine over repair what’s there

Sent from my iPhone using Tapatalk Pro

I would thoroughly check for an exhaust leak; if it were the lifters or cam, it should increase and decrease with engine RPM. You could also add a heavier-weight oil or an oil additive to the crankcase and see if the sound changes.

 

[BRTreedogs]

Black stone will mail you a free oil kit.
Then you send in payment with your sample, or pay online.

Free Test Kits | Blackstone Laboratories

Not much in life is truly free, but these kits are. All it costs you is the time it takes to fill out the form. Just one more reason to love Blackstone!

www.blackstone-labs.com

 

[TaperPin]

We forgot to ask if anything happened to the engine before the tapping started, like it overheated, was used to tow a trailer across country, or if the oil is changed regularly.

Our youngest is famous for believing modern engines don’t need oil and has ruined more than one by letting the oil level get so low the lifters sing, then topping it off. lol

 

[Mattyq17]

Is it throwing any codes? My 2012 5.3 GMC had one of the AFM lifters collapse and made a tapping sound. I replaced all the lifters, and it was good for a few thousand miles. Tick came back and my son wanted to buy the truck, so he and a friend tore it apart, had the heads freshened up, and put an AFM delete kit in, (new lifters, pushrods, cam, water pump, and some other stuff I can't remember), and it has gone away and runs fine now. Total cost was around 3K if I remember correctly. Not really hard to do if you take your time and are mechanically inclined. Him and his buddy are 18 and did it at his buddy's dads shop after work and over a couple weekends. 5.3s are notorious for lifters collapsing not sure if that's an issue with the 4.8 but it might be as they have the same block just different heads.