Engine Tick/Knock 2005 97k Miles

[wesman43]

Okay, so I have had this for a while now, it's been doing it since I bought the truck at 90k about 4 months ago. It recently got louder when I changed my oil to Valvoline full synthetic from Castrol High Mileage synthetic blend, and I used an ACDelco filter. I know Captain has had success with getting rid of this noise, or something similar, and it's annoying the heck out of me. Every mechanic I have asked says "Oh that's normal, probably a piece of carbon somewhere or something" and it didn't really diagnose OR suggest on how to solve it. Ignore the directional sound from my phone, its jacked up so just focus on the actual sound I know that it's not a rod knock or spun bearing or anything because it goes away at higher RPMs but sounds EXTREMELY, i mean EXTREMELY like a diesel at around 1k-1,500 RPM. So here is the vid (I posted this on someone else's thread but I don't want to hijack it so I'm starting a new one)

[video=youtube;9cD4LIMPYuY]http://www.youtube.com/watch?v=9cD4LIMPYuY[/video]

 

[gmcman]

Remove the serpentine belt and see if the noise goes away. With the belt off, check the water pump for any movement back and forth.

 

[CaptainXL]

Ah, the infamous dieseling noise. There was a similar post about some Ford's which have a similar condition.

As with some other Ford engines, this is supposedly caused by the VVT or variable valve timing and gumming up of the phaser and CPAS. Seems like a lot of members here notice it just after buying the truck. It seems to be due to a general lack of maintenance.

My engine sounded similar when I got it at 100K. Not anymore. To solve it I flushed the engine a number of times and also made sure to use synthetic 5W-30 and the ACDelco PF-61e filter.

When you have completed the second flush I would change the CPAS. Never mind about how it looks (if it's dirty or clogged or not). Just replace it as I am assuming the previous owner neglected the vehicle (therefore the oil change interval) to some extent.

The entire VVT system on our vehicles is very fickle and requires timely oil changes and proper maintenance of the engine. Any amount of dirt, sludge or varnish in the engine will compromise the workings of it.

For instance in the past year I have noticed that when I accelerate the engine no longer surges when try to get on the highway or passing. The VVT now works extremely smooth and provides power over most of the rpm range. Before it would just kick in at around 4K. So to me the phaser seemed stuck which it probably was.

Overall the conclusion that I have come to is that the flushes (combined with using a quality synthetic and proper oil filter) unclog any passages and vanes and remove varnish in the VVT system which can cause parts to hang up.

 

[wesman43]

Ah, the infamous dieseling noise. There was a similar post about some Ford's which have a similar condition.

As with some other Ford engines, this is supposedly caused by the VVT or variable valve timing and gumming up of the phaser and CPAS. Seems like a lot of members here notice it just after buying the truck. It seems to be due to a general lack of maintenance.

My engine sounded similar when I got it at 100K. Not anymore. To solve it I flushed the engine a number of times and also made sure to use synthetic 5W-30 and the ACDelco PF-61e filter.

When you have completed the second flush I would change the CPAS. Never mind about how it looks (if it's dirty or clogged or not). Just replace it as I am assuming the previous owner neglected the vehicle (therefore the oil change interval) to some extent.

The entire VVT system on our vehicles is very fickle and requires timely oil changes and proper maintenance of the engine. Any amount of dirt, sludge or varnish in the engine will compromise the workings of it.

For instance in the past year I have noticed that when I accelerate the engine no longer surges when try to get on the highway or passing. The VVT now works extremely smooth and provides power over most of the rpm range. Before it would just kick in at around 4K. So to me the phaser seemed stuck which it probably was.

Overall the conclusion that I have come to is that the flushes (combined with using a quality synthetic and proper oil filter) unclog any passages and vanes and remove varnish in the VVT system which can cause parts to hang up.

Thanks! What do you recommend for flushing it and procedure etc? I was planning on changing the CPAS as well anyways, so add that to the list gonna be replacing the serpentine belt (procrastination) and the wheel hub tomorrow because its buzzing really loud on the right side front when I curve to the left

 

[CaptainXL]

Thanks! What do you recommend for flushing it and procedure etc?

There is no specific procedure to follow. All I do is hop on down to Advance Auto and pickup two quarts of Gunk or K&W engine flush. When home I drain two quarts of oil to bring the level down to approximately 5 quarts. I do this when the oil is still hot. I then dump two quarts of flush in. Then follow instructions on bottle.

One quart of flush would usually be enough to do the job but we have a 7 quart oil pan...so two is better IMHO. Of all the flushing solvents available over the counter I think K&W is the best. I am biased though. If it smells really bad like it would take paint off your bumper then that's a plus in my book. There are specific acids and solvents in good flushing products. But suffice it to say, most engine flush products mainly are No.1 and No.2 fuel oils (Kerosene & Diesel). To save money I have and do use Kerosene to flush my engine. I just fill up used quart bottles from the kerosene I use in my torpedo heater. It's really up to you what to use. But just keep in mind that two quarts of any kind of flush is not enough to significantly reduce the viscosity to any dangerous level. I feel very confident in doing flushes to remove varnish. It is not recommended to flush an engine that is heavily sludged.

K&W has the following ingredients:

COMPONENT CAS NUMBER % BY WT.

PETROLEUM DISTILLATE (No. 2 Diesel) 68476-34-6 80 - 90

XYLENE 1330-20-7 5 - 10

2-BUTOXY ETHANOL 111-76-2 3

ACETONE 67-64-1 <5

ETHYLBENZENE 100-41-4 <2

 

[xtitan1]

Sorry if this is a dumb question but would sea foam be another type of engine flush like the gunk or k&w products you mentioned above, or is sea foam different?

Also, after the flush has done its thing, do you put two quarts of new oil back in? Or do you just totally change the oil and filter after a flush ?

 

[CaptainXL]

Sorry if this is a dumb question but would sea foam be another type of engine flush like the gunk or k&w products you mentioned above, or is sea foam different?

My only concern is that Seafoam is nothing more than pale oil, some naptha and some isopropyl alcohol in a bottle. It's just not purposed for this job. Nothing really strong in Seafoam that actually can dissolve deposits. Seafoam is mainly used to dry up the oil sump and fuel tank as isopropyl alcohol absorbs moisture so it can be burned. So like Rislone fuel treatment (which also has isopropyl alcohol) it allows water in fuel from phase separation to be burned away. The pale oil in Seafoam to me is just a filler ingredient with no real use. People over at BITOG say pale oil is just mineral oil.

I recommend products specifically labeled and designed to flush.

Seafoam Ingredients:

Pale Oil (liquefier) 64742-54-7 40 - 60%
Naphtha (fuel) 64742-49-0 25 - 35%
Isopropyl Alcohol (fuel system drier) 67-63-0 10 - 20%

http://www.mta.ca/administration/fa...Engine treatment - SeaFoam Sales Co. 2010.pdf

Also, after the flush has done its thing, do you put two quarts of new oil back in? Or do you just totally change the oil and filter after a flush ?

Do a complete oil and filter change. There are some products out there such as Gunk Valve Medic and some compression restorers which can be kept in an engine until the next oil change. But purposefully keeping two quarts of fuel in any crankcase for an extended period of time isn't recommended. For one the evaporation of the fuel oil will make it's way into the PCV system and cause low power by mingling in with the fuel/air mixture.

 

[wesman43]

Okay! Thanks! I will have to do that at my next oil change. I have no clue how sludged up my engine is, I mean its not bogged down so I guess that says something its just been neglected I feel. Hell I was probably the first one to change the transfer and differential fluids on the truck at 90k when I first got it.

 

[CaptainXL]

Let's look at K&W ingredients again. I have commented next to the ingredients what they do. Now compare the ingredients here with the ingredients in Seafoam.

K&W has the following ingredients:

COMPONENT CAS NUMBER % BY WT.

PETROLEUM DISTILLATE (No. 2 Diesel) 68476-34-6 80 - 90

Diesel fuel is a fuel oil and solvent.

XYLENE 1330-20-7 5 - 10

This is a solvent that dissolves heavy oils from steel.

2-BUTOXY ETHANOL 111-76-2 3

Used primarily in oil release agents and dispersants. Keeps oil from sticking to metal.

ACETONE 67-64-1 <5

Main purpose is to lift and remove resins and varnish from metallic engine parts. A metallic prep used prior to painting.

ETHYLBENZENE 100-41-4 <2%

Always a small amount of this in Xylene above.

 

[wesman43]

Wow, never buying seafoam again lmao, giant scam up in here :thumbdown: K&W looks promising

 

[Playsinsnow]

It is not recommended to flush an engine that is heavily sludged

Elaborate? Similar to flushing a neglected tranny?

Been thinking about replacing cpas, but have never flushed any engine I've had. But that's just me. Parked all weekend and ran like a champ on the way in to work.

 

[CaptainXL]

Elaborate? Similar to flushing a neglected tranny?

I see this warning on the bottles of flush and I agree with it.

Usually when an engine is heavily sludged the engine should be at least partially taken apart to scrap out all the crud from valve covers, rockers and such.

If you think about it, if an engine with hard or sticky sludge is suddenly exposed to a solvent, not all of the sludge will completely dissolve in time. It can come off in chunks. If those pieces reach the oil galleries, pump and bearings oil starvation could result.

You can take the oil filler cap off and shine a flashlight down in there and see if there is anything clinging to metal. If it looks relatively clean then it's more than likely safe to proceed.

 

[CaptainXL]

Wow, never buying seafoam again lmao, giant scam up in here :thumbdown: K&W looks promising

It is advertised to clean the fuel system and that is about it. It's not advertised as much on their website for use in oil unless the oil is too thick and needs to be reliquefied.

 

[Playsinsnow]

I see this warning on the bottles of flush and I agree with it.

Usually when an engine is heavily sludged the engine should be at least partially taken apart to scrap out all the crud from valve covers, rockers and such.

If you think about it, if an engine with hard or sticky sludge is suddenly exposed to a solvent, not all of the sludge will completely dissolve in time. It can come off in chunks. If those pieces reach the oil galleries, pump and bearings oil starvation could result.

You can take the oil filler cap off and shine a flashlight down in there and see if there is anything clinging to metal. If it looks relatively clean then it's more than likely safe to proceed.

I've read that too and wasnt sure if it released them from any liability issues. I will take a light to it after work. My only thought now is that if it looks clean, I'll keep doing what I have been and continue to change my oil regularly.

Are we talking about a little film/coating or some thick nasty dirty throttle body looking grime? Can't imagine I would see, or have for that matter, any thick gunk built up that high near oil fill cover. If it has, I assume it has got to be very bad by that point? Thanks CaptainXL

 

[CaptainXL]

I've read that too and wasnt sure if it released them from any liability issues. I will take a light to it after work. My only thought now is that if it looks clean, I'll keep doing what I have been and continue to change my oil regularly.

You can do that, but without doing a flush it could literally take years to clear up a sticking camshaft phaser, if at all.

Are we talking about a little film/coating or some thick nasty dirty throttle body looking grime?

Neither. We are talking about a grease looking paste sticking to metal. That's sludge. If you see only a golden or slightly brown hue down the filler neck then you are ok. That is just varnish. That's the type of stuff we are trying to get rid of and what is causing the phaser to stick.

 

[tbyoda]

Is cpas = camshaft position sensor?

 

[gmcman]

CPAS is the. Camshaft Position Actuator Solenoid. Located next to the power steering pump and is in the RF of the cyl head. Single electrical connector going to it.

 

[CaptainXL]

Is cpas = camshaft position sensor?

PCM cpas fwiw ecm imho


Are these terms showing underlined for you? Popular acronyms are underlined. Hover over them to find their meaning.

 

[tbyoda]

No not on tapatalk on iPad ;(

 

[triz]

AMSOIL Engine and Transmission Flush

You can actually take your CPS out and manually clean it with some carb cleaner. Its a small metal screen that is in there.

BTW I'm not a Valvoline fan. If you want to use a off the shelf oil. Pennzoil Ultra is a very good quality oil. Even better than Mobil One IMHO. As far as boutique oils well I am biased.

How bad do you think the sludge is? Only real way is to pop the valve cover or use a borescope and take a peak. If you have that real bad caked on glass sludge I would not use a flush. For reasons already mentioned.

 

[CaptainXL]

How bad do you think the sludge is?

I have yet to see a 4.2 liter engine with severe sludge. Dont get me wrong you can use a flush to get rid of sludge (Amsoil says it removes sludge) just not the heavy stuck on stuff. Yeah like the caked on glass stuff as well.

 

[wesman43]

I have yet to see a 4.2 liter engine with severe sludge. Dont get me wrong you can use a flush to get rid of sludge (Amsoil says it removes sludge) just not the heavy stuck on stuff. Yeah like the caked on glass stuff as well.

I took a peak and since I switched to synthetic 2 changes ago, its nowhere near as dirty as it was. These are great engines

 

[xtitan1]

This conversation reminded me of this video:


[video=youtube;KC-SxrsgEwo]https://www.youtube.com/watch?v=KC-SxrsgEwo[/video]



Obviously this is an extreme case and required going in there and scraping, but just kind of a good way to see what sludge looks like.

 

[Falcon LS]

I just skim read through the post, as I'm about to log off, but if it's a VVT issue that oil can resolve, I highly suggest Pennzoil Ultra with its GTL basestock (Group III+ vs. Group III Valvoline). It's cured a lifter tick for me on another car, which I couldn't get rid of no matter what I did. PU cleans like crazy.

Another good engine flush would be Liqui Moly/Lubro Moly Pro-Line Engine Flush. This is a "professonal use" product intended for workshops, and comes in a 500 ml can. It recommends 10 minutes on the can, but after contacting Liqui Moly, I was told you can use it up to 20 minutes. Anything more and it's more harm than good. For a slump over 5L, you will need 2 cans.

 

[gmcman]

Just curious if you tried removing the serpentine belt yet? Didn't see any update.

 

[wesman43]

Just curious if you tried removing the serpentine belt yet? Didn't see any update.

Yes I did, and it was still there, removing the belt did help me diagnose a loud squeak/momentary slip on power going on...just replaced it and fixed it lol. I think next step is to do the flush, however, its significantly reduced after the engine has been warmed up for about 10 min or so.

 

[Cloudsurfer]

Reviving an old thread here. My 02, with 115k, sounds not all that different from this, I get a knocking/ ticking sound between 2000 and 3000 RPM. Below, it has the diesel like sound that it seems all the early ones have, and above 3000 it quiets down.

Oil pressure does not vary off the gauge, but as I understand it, these aren't really gauges in the first place.

I have a slight tick at idle, which I am sure is the fan clutch.

I just changed the oil, and have an oil sample off to Blackstone for an analysis, and will report once I get that back, which should confirm presence or absence of high wear metals.

I have not yet pulled the serpentine belt to remove load from the water pump, but will be doing that when I'm back near the truck.

I am not running the AC Delco filter (just found that tid bit of info while reading this thread), but a Bosch. Shell full syn oil.

 

[ek02]

The knocking noise in the 4.2 when cold is usually excessive piston to wall clearance. There was a GM bulletin on it years ago. Customers complained about it, so GM did an extended warranty to 100,000 miles. There was also an issue where the cylinder liners would come loose and destroy the engine. My 2002 Trailblazer has knocked since new when cold, especially when accelerating. It goes completely away when the temp gets to 210 degrees. It has 112,000 on it now. I heard that GM did not selectively fit pistons to the cylinders. They allegedly made all the bores the same size, then assumed that the pistons were all the same size, and just assembled the engine. It did not work out too well. Other GM engines have this knock also. I ran a GM fleet with some Trailblazers until 2010, and some knocked and some did not. Yours is the loudest I have ever heard, but sometimes the noise is exagerated by a video. If it goes away when at 210 degrees, I would not worry about it. It could also be some carbon between the piston and the head. Techron works well to get rid of deposits. I always sprayed water down the throttle body to get rid of carbon knocks, but you can't do it with a Trailblazer. I bought a Seafoam kit once that has a tube to spray it into the throttle body. It worked pretty well to remove carbon on a Trailblazer. A race engine with forged pistons has the same sound when cold, if it has closed exhaust so you can hear it.

 

[Cloudsurfer]

Welp, got around to changing the oil in this thing, and got the analysis back (see attached). No lead, so that should certainly rule out rod knock or anything else bearing related.

The high aluminum and iron could potentially be from piston slap/ scuffing. No chromium, which would indicate ring issues.

At least this would seem to eliminate bottom end issues, but doesn't really help me isolate the knocking sounds I'm hearing.

 

[IllogicTC]

Come to think of it, I have a bit of that "diesel" noise at idle. Only noticeable if you're standing in front of the truck, generally with the hood open and your head near it. Always kinda bugged me. To me it sounds more like I can hear all the individual sets of valves lifting/seating, I don't know how else to describe it.

As for actual tap/tick (you know the sound, like the first few seconds after starting a cooled-off pushrod V8), I only had that the other day with that ridiculous polar vortex or whatever. Literally ticked two-three times, then went away, on start-up. I guess that anti-backflow valve after the oil filter pays off.

But back on the "diesel" noise, think a flush would do me any justice? I haven't yet made the switch to synthetic either (running Castrol conventional right now I believe), and haven't run any sorts of cleaners through the fuel system as I was unsure of which brand would do me the most good. All that "DON'T DO THAT!!!" in the owner's manual didn't help either.

 

[Cloudsurfer]

Come to think of it, I have a bit of that "diesel" noise at idle. Only noticeable if you're standing in front of the truck, generally with the hood open and your head near it. Always kinda bugged me. To me it sounds more like I can hear all the individual sets of valves lifting/seating, I don't know how else to describe it.

As for actual tap/tick (you know the sound, like the first few seconds after starting a cooled-off pushrod V8), I only had that the other day with that ridiculous polar vortex or whatever. Literally ticked two-three times, then went away, on start-up. I guess that anti-backflow valve after the oil filter pays off.

But back on the "diesel" noise, think a flush would do me any justice? I haven't yet made the switch to synthetic either (running Castrol conventional right now I believe), and haven't run any sorts of cleaners through the fuel system as I was unsure of which brand would do me the most good. All that "DON'T DO THAT!!!" in the owner's manual didn't help either.

The "dieseling" sound is piston slap in these things, and while a better oil may help somewhat, it's just caused by poor clearances.

You're not going to hurt anything by doing a flush (if you do it properly), IF you don't have heavy accumulations of crap in the motor.

I'm going to run 1000 miles on mine and pull another oil sample and see what the wear metals look like, but I'm certainly not thrilled to see AL and FE as high as they are in the sample I just sent in. That's typically piston scuffing type wear, which I don't know if the piston slap that these motors are prone to is enough to cause, or if I have other issues.

 

[IllogicTC]

The "dieseling" sound is piston slap in these things, and while a better oil may help somewhat, it's just caused by poor clearances.

You're not going to hurt anything by doing a flush (if you do it properly), IF you don't have heavy accumulations of crap in the motor.

I'm going to run 1000 miles on mine and pull another oil sample and see what the wear metals look like, but I'm certainly not thrilled to see AL and FE as high as they are in the sample I just sent in. That's typically piston scuffing type wear, which I don't know if the piston slap that these motors are prone to is enough to cause, or if I have other issues.

I have a little over 100k on the odometer, I don't see how a proper flush couldn't do some sort of good. I've never sent in my oil for analysis before, but I might start doing so just for monitoring purposes. I've still got my last two oil changes in jugs downstairs, never have gotten around to taking them to the store for disposal, lol.

 

[Cloudsurfer]

I have a little over 100k on the odometer, I don't see how a proper flush couldn't do some sort of good. I've never sent in my oil for analysis before, but I might start doing so just for monitoring purposes. I've still got my last two oil changes in jugs downstairs, never have gotten around to taking them to the store for disposal, lol.

Oil analysis is of indescribable value when it comes to knowing what's going on inside your motor.

If you're at all curious, send a sample in and see what you get back.

 

[IllogicTC]

If you're at all curious, send a sample in and see what you get back.

Just a little...

View attachment 31996

 

[gmcman]

The vid in the first post definitely has a low frequency light knock, also keep in mind the injectors have quite a racket when operating. Being inside the composite manifold the sound doesn't dissipate too much. Just curious if the OP has had any progress.

 

[Cloudsurfer]

Welp, got around to pulling the belt off this thing to let it run for 30 sec without the ancillaries spinning, and the sound is the same. Definitely coming from the motor, and definitely sounds like a rod knock, but the oil analysis would seem to rule that out.

So, what else could be making such a racket here?

 

[nagyiii]

i dont mean to be a big dummy, but what is a CPAS?

 

[IllogicTC]

i dont mean to be a big dummy, but what is a CPAS?

I guess they don't have that put in the acronym script yet.

Camshaft Position Actuator Solenoid. Type that plus TrailBlazer on Google and you'll see exactly what it looks like. Oil goes up from the pump to the CPAS, where the CPAS acts as a valve directing oil into the exhaust cam actuator, which allows for variable valve timing. Other GM engines also use this thing (Ecotec 2.0, 2.2, 2.4 have two, one for the intake and one for exhaust), though it's a little different and they of course all have different part numbers.

 

[nagyiii]

thanks