2 Misc Engine Q's

Uncle_Joe

Original poster
Member
Jul 26, 2019
15
Texas
I learned the hard way that the cyl head bolts are "stretched"??? so if they are not removed the correct way they will snap.
I saw a video to remove them hammer thebolt down, turn a little, hammer again, etc. Is this true? Also, being i have the inline 6, cyl 5 and definitely 6 are tucked under the windshield so how would i whack the bolts if i don't have a clear shot without removing the whole engine?

I notice there seems to be a pattern with GM engines or is it just my luck???? I had a 9x olds and now, a trailblazer - i see significant carbon deposits on the pistons. The olds also had to be cleaned out - mechanic said alot of carbon. I also have a 96 mitsubishi that doesn't have anywhere close as much carbon. As i said, is this a GM thing??

TIA
 

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,641
Tampa Bay Area
Welcome to GMT Nation...

No. It is NOT a just problem relegated strictly to GM Vehicles. But it is NOT necessary to remove the Engine Head to De-Carbonize the Piston Heads, Top Two Impacted (stuck within the Grooves) Compression Rings and Upper Internal Cylinder Valve Seats. Check with @gmcman for his Epic 'Thread' (pun intended) when using Berryman B-12 Solvent and ACDelco Top Engine Cleaner to accomplish this task. Fortunately...because these Liquid Solvents can be directly introduced into all of the Cylinders via the vacant Vertical Spark Plug Holes in the Inline 6 LL8 Engines... the Solvents will get equally distributed to perform their proper Carbon Busting effects.

Regarding the other problem of experiencing Easily Broken TTY Bolts. This issue has to do with the universality of the Principles that govern How TTY Bolts "Stretch and Hold". In a Nut Shell... its a Toss Up between Elasticity versus the Ultimate Plasticity of the metal materials that will rebound only up to a certain amount of stretch and then... PASS THE FINAL POINT OF METALLIC PLASTICITY AND FRACTURE.

Once these TTY Bolts reach that Final Stretch Point... there is NO GOING BACK. The next event WILL cause the Bolts to FAIL on an Atomic Level of Plasticity. When you try to 'unwind' these Bolts...the Metal will become so badly crystallized that the Bolts suddenly Snap-Fail completely... in Reverse.

Unfortunately... "The Broken Head Bolt Debacle" and I ...are "Old Friends" and I can tell you from intimate personal experience that the "Hammer ...Then Turn Method" is a means to provide Hope to any Mechanic... only to Dash that Dream as soon as any One of those M11 X 2.00MM Head Bolts Snaps Clean Off. The only way to compound this problem is to imagine (as I once did...) that it is possible to Drill out the Broken Head Bolt remnant and use a Reverse Twist Drill Bit to eat into them backwards and unwind them... WHILE THE ENGINE HEAD IS STILL SITTING ON THE ENGINE BLOCK. It's Not.

Nope... BAD IDEA.

This problem is something akin to having your favorite Girlfriend telling you,

"Honey... But I'm only a LITTLE BIT Pregnant..." ;>(U)

The ONLY way to get through this Nightmare ...is to continue removing ALL of the Head Bolts. Some will come out with loud "CREAKING" sounds... but more than likely... More than Half of them WILL JUST SNAP RTF OFF. So... Just roll with it... and WAIT UNTIL THE ENGINE HEAD IS COMPLETELY REMOVED before attempting to counter-drill and extract the remaining Head Bolt Remnants. Just be aware that you should expect an ENORMOUS Release of Kinetic Energy as each and every Bolt that Snaps Clean Off essentially does THIS:


Do NOT attempt to re-use ANY of the Old Head Bolts that Do NOT Snap Off. Purchase the UPDATED version as per @m.mcmillen 's experience with using the UPDATED flavor from Fel-Pro ... as their Bolt Stretch Parting Lines have been elevated to a higher position along the Bolt Shanks to reduce the chance of them Snapping Off during future R&R efforts.

Here are some images I took of what happens ...More Often Than NOT... when trying to Unbolt the GM Atlas LL8 4.2L Engine Head Bolts for both the 2002 AND the 2004 GM 4.2L Engine Heads:

43350764162_0df0646fc8_z.jpg43350764332_359db9b196_z.jpg42528551915_9794cfacc9_z.jpg42528539935_2c9600bd0b_z.jpg43433035741_ae60e53b7c_k.jpg42574128875_943abd03a1_z.jpg41669179890_c00ac8b8f2_z.jpg42717491014_0f6f7c1d54_z.jpg29562984848_4489a545e2_z.jpg42717490644_c5de3e333f_z.jpg29562984698_33f348e6d4_z.jpg43433602891_e96906ce66_z.jpg42717490294_d8ff1458bd_z.jpg43478981851_dd76f5c10b_z.jpg43350764302_34912519af_z.jpg43350764232_e993780f86_z.jpg43433036741_9f4ebb7557_z.jpg43430353812_3a8c368493_z.jpg43385765222_79ed59047c_z.jpg
 
Last edited:
  • Like
Reactions: BrianF

BrianF

Member
Jul 24, 2013
1,192
West central Sask.
Yep^^^^^^^^ got to love TTY bolts!!!! I wont touch them!

As stated, you can do piston soaks easy enough on the Atlas. Another alternative is to run a high quality, high detergent motor oil in shorter change indexes. Pennzoil Platinum touts itself as having a high level of cleaning ability, as would any Dexos oil. Unless you have an oil burning Toyota, this is a slower, easier way to unstick rings. Also you can introduce water into the intake stream. A bit harder to do with the location of the MAF but you need to get it up to operating temp and introduce a small stream of water from a squirt bottle directly into the throttle body. It atomizes and helps break down deposits on the piston crown.

Now, one has to ask: Why is it full of carbon? Could be a lazy O2 sensor, dirty MAF, vacuum leak or something causing it to dump extra fuel into the cylinders.

I have never run into carbon issues on any of my vehicles. I use quality oil at thought out intervals, quality fuel, keep them in decent operating condition and some spirited driving once in a while.
 

gmcman

Member
Dec 12, 2011
4,656
Welcome @Uncle_Joe ...I just went through a cleaning as I was surprised my piston crowns had a good bit of build up.

First of all...

What oil are you using?

What are your oil change intervals?

What fuel are you using? Any particular station and what octane?

With the engine running, check for vacuum through the large port in the valve cover.

Screenshot_20190728-184538_Gallery.jpg

Place your finger on the port and wait about 10 seconds then release, you should hear air rushing back in.

If that checks out, then the molded hose between cyl 3&4 on the intake manifold should be clear and drawing vacuum.

What is your avg MPG? Does the engine run or idle rough? Any codes stored?

Hopefully we'll get this sorted out.
 

Uncle_Joe

Original poster
Member
Jul 26, 2019
15
Texas
Thanks for the replies.
The 2 questions were 2 seperate inquiries looking back on the years of owning the truck.
So car companies should put the sticker that is on electronics "No serviceable parts inside."

I use 5w20 Valvoline dino every 4000miles.
I get gas at QT or Racetrack - There is a gas storage place with many tanks. Drive by any day and you will see trucks from all gas stations lined up to get gas so likely not much if any difference between brands. + my 3Kgt uses the same gas and doesn't have this problem.
 

Maverick6587

Member
Dec 16, 2018
730
Sterling Heights, Michigan
After cleaning the top end of the cylinders. Would putting in an oil catch can be advisable?
I would assume that would keep the valves cleaner.

@gmcman - Did you put in an oil catch can after you did that extensive cleaning on yours?
 

gmcman

Member
Dec 12, 2011
4,656
After cleaning the top end of the cylinders. Would putting in an oil catch can be advisable?
I would assume that would keep the valves cleaner.

@gmcman - Did you put in an oil catch can after you did that extensive cleaning on yours?

Part of me says yes a catch can would work fine, and this has been proven by many people on all makes of vehicles.

In my recent experience, the can worked until I failed to notice the small mesh screen in the lid. The lid was secured to the vehicle and I would reach down to remove the body to dump the oil. Not seeing the screen I forgot to clean it resulting in a clogged PCV system. Knowing this now, I believe one would work as mine was catching about 2-3 oz per 3K miles give or take.

I had the can installed before my rod bearing replacement and top end cleaning. I may use it again, just want to see how the motor does on the next few oil changes.
 

gmcman

Member
Dec 12, 2011
4,656
I use 5w20 Valvoline dino every 4000miles.

I would like to speculate this could be one of the reasons of your carbon build up.

The 4.2L is spec'd for a 30wt oil when hot, and using a 20wt dino which has a lower flashpoint as well as being thinner, is likely getting past the rings.

I would recommend a 5W-30 synthetic knowing of your current motor issue. Slightly more expensive but over the course of 4K miles it's negligible.

I went from a 5W-30 Synthetic to 0W-40 and the motor sounds and runs great. If you're worried about a thicker oil you can skip the 0W-40 and just use a 5W-30.

If that were my motor, I would start with using Amsoil Pi fuel additive or BG44K in each tank for a few tanks. Then take a look inside and see if you will need a top engine cleaning.

The Amsoil Pi and BG44K work extremely well and clean over time. Using something like Pennzoil Ultra Platinum for a few oil changes will help to clean up the rings of that have some build up.

If you have a Costco membership I would recommend filling up there. I do understand about stations using whichever fuel can be bought at the best price, so it can be a crap shoot. Costco and other top-tier stations like Chevron and Shell I'm pretty sure also spec a certain amount of additives for their fuel.
 

Maverick6587

Member
Dec 16, 2018
730
Sterling Heights, Michigan
I had the can installed before my rod bearing replacement and top end cleaning. I may use it again, just want to see how the motor does on the next few oil changes.
I know there are a few places you can connect the hoses for the catch can. Which ports did you use and how much oil were you getting per month/oil change?
 

gmcman

Member
Dec 12, 2011
4,656
I know there are a few places you can connect the hoses for the catch can. Which ports did you use and how much oil were you getting per month/oil change?

Post# 13,607 may open right up to it. That was my catch can install, was capturing 3-4oz I guess, every 3-5K miles.

 
  • Like
Reactions: Maverick6587

Maverick6587

Member
Dec 16, 2018
730
Sterling Heights, Michigan
Post# 13,607 may open right up to it. That was my catch can install, was capturing 3-4oz I guess, every 3-5K miles.

Yup, opened right to it, thank you. Just verifying because I could exactly see the bottom connection. Are the catch can hoses attached to the top and bottom of the PCV hose ports?
 

gmcman

Member
Dec 12, 2011
4,656
Yes, I cut the factory hose and added the second hose. If you return to a stock setup you will likely need to source the OEM molded hose.
 
  • Like
Reactions: Maverick6587

Forum Statistics

Threads
23,273
Posts
637,498
Members
18,472
Latest member
MissCrutcher

Members Online

No members online now.