goyakpacking

I suddenly started hearing a ticking noise after starting the engine. This has never been there. I am at 96K miles and have not had this until now.

It only does it on start up for a few minutes after the vehicle has sat long enough to cool down.
It changes (ticks faster) as RPMs increase, (ticks slower) as RPMs decrease.
The tick occurs when load put on engine, but only in the first few minutes after cold start-up) (Load = Emergency brake on, in gear, and giving it a little gas to increase RPMs.
All ticking goes away in under 5 minutes after cold start up.
Tick seems to be in the upper rear of the engine. I have not checked to see if I can determine if it is one side or the other.
Does not do it if engine is normal operating temperature, shut off, and started right back up.
I suspected gas at first and added high test when down to 1/2 tank. I have been running that for about 50 miles.
Otherwise running normal, smooth, no abnormal noise...no smoking exhaust.
Oil level is good. Oil pressure seems normal (no noticeable change to dash gauge). Oil Change not even close to due either by vehicle calculator or by any standard interval.
Oil is synthetic and always has been. Always changed on or before maintenance interval. Oil Filter changed each oil change.
I just added 6 oz of seafoam product to the oil hoping something is dirty and I have a sticking lifter? I have 10 miles on this. Planning on doing a oil change soon.

Update 8/26/16
I found the source of the noise is a sheared off exhaust header bolt. It is sheared about a 1/4 inch inside the head. It is the very rear bolt on the drivers side. I found this after reading numerous complaints of my same symptom. Many forums indicated said to check the header bolts for break off. Why there is no recall or GM help on this, if it happens so much, is beyond me.

So.....I called a dealer in Las Vegas to get an idea of what it costs to repair this. I was quoted $4500.00. You gotta be $&#@'ing kidding me. I asked 3 times if there was an error in what he was looking at. He said the head on that side has to be taken off and the bolt extracted if possible. More $ if the bolt can't be extracted, and the head has to be replaced.

Can this dealer repair cost be possibly true?



Update 9/1/2016: Some big thanks to some Facebook friends that recommended Kral Auto Parts. www.kralautoparts.com

I ordered part # KAP169. This is a specialize part made specifically for the very rear driver side header bolt (When that bolt or bolt head shears off). At least for my year of the Chevy 6.0L engine. This was delivered to my door in three business days for just under $40 including postage and handling.

I have less than 1 hour labor dismantling the dash and moving the interior engine cover off to the side to initially troubleshoot the problem. Man some engineer must have made this cover removal purposely difficult. What happened to popping a couple clamps and sliding the cover back and lifting it out of the interior? Now you have to remove 2 dash panels, and the cup holder/glove box tilt out assembly, to get to the clamps, and move the cover. I never did figure out how to get the cover out of the vehicle and out of the way.....if that is even possible?

Next I made my own welded modification the the part I ordered. Rather simple if you have the tools. The part modification, part installation, including reattaching the engine cover, dash panels, and Cup/Glove box assembly, all took a little less than an hour.

So this repair cost me $40 and 2 hours labor. I consider it to be a permanent fix.

Let me explain my modification and reasoning.

Since it is nearly impossible to extract the sheared off Header Pipe bolt (without great expense) KAP manufactures a part that bolts to other existing threaded holes on the engine using 2 bolts that are supplied in the kit. The part they manufacture positions a third bolt that is screwed in and presses over that bolt hole of the Header Pipe, where the sheared off bolt is located. If the head of the broken bolt was simply popped off and the shaft of that broken bolt protruded up into the Header Pipe bolt hole, this KAP part would work perfectly as is. Slap it on with the two provided bolts, crank down the 3rd set/clamping bolt and you are done.

In my scenario my bolt had sheared about 1/4 inch inside the aluminum head of the engine. I was concerned if I simply pushed the Header Pipe up to the Head with the clamping force of the KAP part, up and down vibration of the Header Pipe might occur. There would be no bolt stud to stop that.

So my modification was to simply weld the correct diameter piece of bolt onto the end of the KAP clamping bolt. I then took a depth measurement of the Header Pipe's cast iron....at the bolt hole location. I trimmed off the welded on extension to the proper length. This provided a stud that went inside the Header Pipe hole to prevent any up and down movement.

My concern should I not anchor this end of the Header Pipe, up and down vibration might cause other Header Pipe bolts to break.

This part is installed and has been tested both on the engine hot, as well as cold. My noise its gone...it no longer sounds like an engine that is about to break down. Thanks friends....and thanks KAP! Onions to GM for a known problem, and GM Dealers taking advantage to make big $.



Very Rear Drivers side Exhaust Header to Head, bolt broke off.




Very Rear Drivers side Exhaust Header to Head, bolt broke off.



The KAP part as is right out of the box.




Test fitting prior to modification




The modified part with a new coat of heat flat black paint.




The installed part. One of the existing holes I had to use to mount the part had a ground strap attached. I ground the paint off the part on the engine side, as well as the other side were the ground terminal was reattached....to maintain a good metallic bond.




Part install and pressing in on the Header Pipe at the broken bolt location. It works like a champ!

canucklehead

Where in the engine is it coming from? Top, bottom, front back? You can get a cheap stethescope from a parts store to narrow it down. Did the seafoam make it go away? If not try valve medic. It will thin the oil and help it to get into whatever space its not.
Also you could make the switch to high mileage oil. I did and my oil pressure came up a bit, and the extra zddp helps with wear etc.

canucklehead

If its not the top of the engine it could be a vacuum pump or a piston slap........
If you google the issue you will find info on those two.

goyakpacking

I haven't tried locating it to any area...but from the inside of the cab I am getting the notion it is upper rear. The Stethoscope idea is on my list. I normally stick a screwdriver handle to my ear. I don't know if the Seafoam has had enough mileage to do anything yet (about 10 miles on it). Thanks for your idea's. I will post the final conclusion if/when resolved.

Its coming up on needing new plugs. I didn't know if this might be a cause? To me it sounds like lifter noise.

canucklehead

If it is a lifter or something like that....valve medic will quiet it in a minute of idling. If it does then you have narrowed the problem.

goyakpacking

I found the source of the noise is a sheared off exhaust header bolt. It is sheared about a 1/4 inch inside the threaded hole the aluminum head. It is the very rear bolt on the drivers side. I found this after reading numerous complaints of my same symptom, and many said to check this. Why there is no recall or GM help on this, if it happens so much, is beyond me.

So.....I called a dealer in Las Vegas to get an idea of what it costs to repair this. I was quoted $4500.00. You gotta be $&#@'ing kidding me. I asked 3 times if there was an error in what he was looking at. He said the head on that side has to be taken off and the bolt extracted if possible. More $ if the bolt can't be extracted, and the head has to be replaced. Minimum 29 hours labor.

Can this dealer repair cost be possibly true?

canucklehead

Muffler goop.......jeez what rotten news. Can you live with it, now that you know its engine external?

canucklehead

There are aftermarket brackets thay ou can buy that bolt onto the good bolts and press down on the flange where the bad bolt broke off. This could seal the leak......google it.

goyakpacking

Someone just turned me onto Kral Auto Parts. They make Manifold Bolt repair kits that uses other threaded holes that exist in the block. Then a a side flange that is threaded that goes over the existing hole. A set screw/bolt threads down through the flange, over the Header hole, to snug the header back up to the head. I do believe part KAP169 is going to be the fix for this. $32 + Postage.....and a job I can do with little trouble.

Canucklehead this looks like what you must have been referring too?

Doing a re-inspection on the block tomorrow to see if the holes are there for this part. Stay tuned.

8/27/16 Yep Holes there for part # KAP169. I have to deal with a ground strap in one of the block holes but this should be an easy fix.

canucklehead

Good luck. I hope this issue has been fixed on the newer vans.....I don't want to have to go there.....lol.