Jump to content
  • Sign up for FREE! Become a GM-Trucks.com Member Today!

    In 20 seconds you can become part of the worlds largest and oldest community discussing General Motors, Chevrolet and GMC branded pickups, crossovers, and SUVs. From buying research to owner support, join 1.5 MILLION GM Truck Enthusiasts every month who use GM-Trucks.com as a daily part of their ownership experience. 

beefey

HELP Bad News Sounds Coming From Engine (VIDEO)

Recommended Posts

Posted (edited)

Hi Guys--

 

I just got my truck back from a local mechanic to fix a broken exhaust manifold bolt (photo attached).

Tonight I start up my truck and hear THIS! Could he have put too much heat on the block and distorted a push rod guide or something? Doesn't it seem too coincidental that this nasty noise pops up RIGHT when he touches it?

Thanks much for your help!

 



 

Exhaust Bolt.jpg

Edited by beefey

Share this post


Link to post
Share on other sites

Pull your dipstick and check the oil for glitter.


That sounds like a lower end engine knock for sure. If you rev it up and the knock gets faster/louder it's probably a rod bearing.

Share this post


Link to post
Share on other sites

Lifters will make sound that is about half the speed of the crank because of the camshaft only working one lifter at a time. The noise in the video sounds like it goes along with the speed of the crank.

 

To me that says rod bearing all the way.

 

 

  • Like 1

Share this post


Link to post
Share on other sites

How this happens. Many of the head Exhaust manifold bolt holes are Blind ( sealed bottom). It is possible if the hole was drilled and re tapped

that a bolt is now in the water jacket. This can allow water in the oil in some locations.

 Check the oil for any milky~ness. 

Share this post


Link to post
Share on other sites

hammering pretty loud. sounds like it has a lot of rough miles on it...its too late to do anything about it now. 

Share this post


Link to post
Share on other sites
Posted (edited)
1 hour ago, Formulabruce said:

How this happens. Many of the head Exhaust manifold bolt holes are Blind ( sealed bottom). It is possible if the hole was drilled and re tapped

that a bolt is now in the water jacket. This can allow water in the oil in some locations.

 Check the oil for any milky~ness. 

That's a great insight. That could have happened. I don't see any obvious water contamination but it is probably pretty difficult without an oil analysis. The truck literally came back from the mechanic earlier today and has only had 25 miles on it since the service. Could coolant in the oil shell out a rod bearing that fast?

The coolant expansion tank is not black by any means...

It never made any noise really at all until this service was performed at the mechanic.

Oil Stick.jpg

Edited by beefey

Share this post


Link to post
Share on other sites

No, if there was enough coolant in the oil to cause problems, it would be pretty obvious to the naked eye.

Share this post


Link to post
Share on other sites
Posted (edited)

I don't think that damage could happen overnight. Coolant in the oil usually takes out the cam bearings first resulting in low oil pressure. That engine is just worn out.

Edited by It's Tim

Share this post


Link to post
Share on other sites

Just a coincidence after repairs.

Rod knock IMO.

How many miles. 

And for us curios minds, oil changes were done at how many miles?

:)

 

  • Thanks 1

Share this post


Link to post
Share on other sites

55K Miles-- I bought the truck at 35K Miles and changed with the ECM meter with mobile one 5w30.

Share this post


Link to post
Share on other sites

I a mechanic and really want to think it is a coincidence that it happened right after the manifold bolt repair but, really only 55k miles on engine? It can be hard to be sure if it’s a rod and/or cam/lifter, try disconnecting each fuel injector one at a time if it’s a rod noise should change when unloaded. Are those correct manifold bolts?

Share this post


Link to post
Share on other sites

A mechanics stethoscope might be able to help you narrow down where the sound is coming from.

Share this post


Link to post
Share on other sites

I feel like running it could lead to catastrophic failure given it's so bad. Is that unfounded?

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.




×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.