yet another lovely 4.2l valve tick

[kickass audio]

I know there are like 100 of these on here but I figured mine is a little different and I love troubleshooting so here is my issue.

the description of my problem:

The past few weeks my 4.2 has been making the typical complaint of sounding like a diesel engine when at idle all the way up to about 1k RPM. The noise seems prominent on the exhaust side toward the rear, possibly at piston 5 or 6 on the exhaust valve. A week ago just for the heck of it i pulled the coil pack on piston 2 and 3 and found that piston 3 had a little oil in the well. I couldn't find any fresh leaks or traces of oil from the valve cover to the engine in that area but the plugs were replaced about 15k miles ago so it is fairly recent. Like another member on here had discovered if I take the PCV hose and plug it after it gets enough vacuum it will then stop the diesel noise. If I continue to hold the hose shut after about a minute you will hear a clacking noise that sounds like a push rod tapping onto the rocker arm. The engine runs great though despite the noise. I have 0 issues with performance, the fuel trim is perfect

Here is what I am thinking to do:

I have never ran an engine cleaner through the engine though I always use mobile 1 oil and change it at every 3k miles (yea I know its too often for our engine but I like to be overkill with protecting it). I would think that at the mileage I am at, 130k that a cleaning wouldn't be a bad idea but i am concerned about getting some gunk caught up in another part of my engine.

My plan was to take the valve cover off to replace the gasket since I had some oil in the spark plug well and suspect it to be leaking from the valve body and cover. While I was in there I was going to see how hard the lash adjusters would be to get to and maybe clean them up or otherwise re-adjust them since I doubt they were touched since the factory built the engine. I do NOT want to pull the timing chain and cam's out of the engine. I do not feel comfortable or willing to get that far into the engine. lol.

Here is what I want to test:

I want to do a compression test on all the pistons and then see how it reads as well as check the oil pressure at the filter and see if that is too low or anything.

If anyone has any suggestions on what I should try for a cleaner or if I should stay away from that please let me know. Also if anyone has insight on the valve lash adjusters on our engine I would appreciate the feedback. I looked at the service manual and can see where they are but cannot tell if these are reachable with the cams in or out. iirc another member did theirs with the cams in but I also want to clean them out and make sure they aren't stuck or anything.

 

[kickass audio]

lets bump this up. Anyone have any suggestions for cleaners and if the adjusters can be reached without pulling the cam shafts?

 

[turner56]

I've had my trailblazer since Jan. 2013 and last July my engine began ticking. I took it to a shop and dealer and they said they couldn't identify an issue. It has gotten noticeably louder since then. I took it to a 3rd repair shop two weeks ago and they said it was the lifters and recommended I get an engine flush with my next oil change but besides that to not worry about it. The sound the tick speeds up with increased RPMs but is never audible from inside the cabin. I haven't noticed any smoke, drop in performance or mileage. Any idea what this could be? I'm not sure if it's valvetrain or exhaust related. I run Mobil 1 full-synthetic and an extended performance filter. Any help would be appreciated!

Here's a clip I made a few minutes ago to help.

 

[kickass audio]

That is the infamous sound our engine seems to make. If you plug the PCV vent that goes to your air intake resonator (that black box that says vortec) with your finger, after a minute of it applying vacuum you will have the tick noise go away. Mine seems more dominate on the passenger side toward the rear, like around piston 5 or 6 for the exhaust valves. I too run mobile 1 synthetic but the previous owner got his oil changed at jiffy lube and I am not a fan of their service and products of choice. I am really wanting to put some engine cleaner through but am terrified of blocking an oil passage and starving the engine from oil in that location and end up having to get a rebuild from it. I don't think the sludge is bad in it but I did not remove my valve cover yet to confirm on this. Mine sounds great when its cold but when it warms up I only hear it at idle up to 1k rpm. I do hear it in the cabin but it is not that loud. There is no shuddering on the engine at all. It runs perfectly smooth. No shudder in the wheel or even on the engine.

I just want to see what everyones opinion is on a nice, reputable engine cleaner on the market. Cheap or costly I will give it a try if it has a good Rep.

 

[Hypnotoad]

I've found that oil additives don't usually fix problems like this. Of all the engine sounds I've had over the years in motors, only one has been quieted with an oil additive. What I used was Rislone. It's with a try anyway, the stuff only costs about as much as a quart of oil.

 

[turner56]

That is the infamous sound our engine seems to make. If you plug the PCV vent that goes to your air intake resonator (that black box that says vortec) with your finger, after a minute of it applying vacuum you will have the tick noise go away. Mine seems more dominate on the passenger side toward the rear, like around piston 5 or 6 for the exhaust valves. I too run mobile 1 synthetic but the previous owner got his oil changed at jiffy lube and I am not a fan of their service and products of choice. I am really wanting to put some engine cleaner through but am terrified of blocking an oil passage and starving the engine from oil in that location and end up having to get a rebuild from it. I don't think the sludge is bad in it but I did not remove my valve cover yet to confirm on this. Mine sounds great when its cold but when it warms up I only hear it at idle up to 1k rpm. I do hear it in the cabin but it is not that loud. There is no shuddering on the engine at all. It runs perfectly smooth. No shudder in the wheel or even on the engine.

I just want to see what everyones opinion is on a nice, reputable engine cleaner on the market. Cheap or costly I will give it a try if it has a good Rep.

I tired plugging the PCV valve and the noise did not go away.

 

[Texan]

In case you missed this, I would read all of this thread: "Dreaded knock sound is starting" by gmcman started 13 April, 2014.

They are hydraulic lash adjusters and I do not think that they are adjustable.

 

[jsinga]

You might try a Lubegard flush and protect pak. Their products are as good as any. OEM's have used lubegard red in transmissions. I have seen the power steering juice stop moaning in just a few minutes.

JS

 

[Niklaus]

I have never ran an engine cleaner through the engine though I always use mobile 1 oil and change it at every 3k miles (yea I know its too often for our engine but I like to be overkill with protecting it).

I read that with Mobil 1, the full synthetics don't even start to kick in until 3k miles and at that point you are throwing your oil out and it's a total waste when you could easily go with an oil change every 6k and some would consider that to still be too early. You are not protecting the engine by doing this. You should trust the OLM.

 

[jimb442]

kickass, mine does exactly what yours does! I realize this is an old post but hopefully somebody can get in here if they have any answers.

I have the same sound...like a lifter at idle that absolutely goes away when plugging the "PCV" tube for about a minute. I just did an engine flush as the last attempt before looking at the lifters and I just don't think the flush is going to resolve anything but if it does I will post it.

 

[gmcman]

Mine is almost dead silent now when running and hot, it goes through stages and sometimes after a minute or 2 of startup when cold it will make a noise but I think this is my exhaust manifold as the last bolt is broken.

Either way, I pulled my valve cover, and most all the lifters had some type of buildup in them. I cleaned a bunch with mineral spirits, kerosene, and while trying to free them there was dark fluid coming out of the bleed hole.

I'm not sure exactly but I would suspect they need to stay pumped up, but these were basically locked into the "pumped" position. I needed pliers, and solution just to get them to retract and then I could work them against the spring inside to clean them out.

They are pricey to replace and you need a special tool.

Can you post a video of the noise?

 

[jimb442]

gmcman...thanks for responding. Did yours quiet down more after the cleaning?
I think mine quieted slightly after the engine flush but is still there clearly. Yeah you are right too about cost. There's what, 24 valves and I think the lifters are about $15 each so it can add up. Obviously I would only replace the "collapsed" one if it can even be identified?
I could try to post the sound but honestly, I would just be repeating what others have already posted....the ticking sound that goes away COMPLETELY while plugging that little hose going from the valve cover to the air box (not sure of the proper name)

 

[Mike w]

Mine went away after adding marvel mystery oil in the oil i use mobil super.

 

[jimb442]

Thanks Mike, do you recall plugging the hose shown in the pic and if so did the ticking go away when you did?

 

[Mike w]

Yes plugging the hose did make it go away.

 

[jimb442]

Well, maybe I will try Marvel on the next oil change and see what happens.

 

[Mike w]

add a full quart of it, when you change the oil after running it sludge will pour out the drain, literally clumps of sludge.

 

[vipergg]

I doubt you need any kind of cleaner if you are using mobil one and changing it at 3k intervals. You are right that is way overkill even for dino oil.

 

[tim.vanderloop]

Just joined the site today as I came upon it when I googled "4.2 vortec inline 6 ticking"

I have a 2002 trailblazer 4x4 with the 4.2 inline. owned it since 2012 when i bought it with 80000 on the clock. No maintenance history for that first 80000 however.. Since I've owned it I've changed the oil every 5000 with regular 5w30.

Mine started making valvetrain noise 2 years ago at 160000. its now at 286000 and getting louder.

I've ignored it for 120000 as it was faint and intermittent. It is now starting to bother me as its getting louder and doesnt go away once she's warm.

Fuel economy is fine and performance is great, no issues there, Also does not use oil or smoke.

All in all a pretty good motor to not use any oil at all at 286000, just this noise is starting to worry me now that its getting loud.

I read the "Dreaded knock" posted by gmcman in its entirety and it seems the lash adjuster cleaning / replacement helped, but did not fix the issue..

I pull a trailer in the mountains in summer often so it gets a workout under heavy load at high rpms a few times a summer. This is about the only time now the noise seems to be less, after working HARD for hours on end.

Any advice would be great. Will it grenade one day if I keep running it with the ticking noise?

Thanks.

Tim.

 

[jimb442]

I wish there was someone that knew these engines inside and out and could once and for all explain this problem. I can't understand how plugging that hose (which creates a significant vacuum in the crank case) would make the ticking go away...which goes away slowly as the vacuum builds. I'm wondering if it somehow does something to oil pressure....perhaps increasing it so oil now starts to reach a lifter that it doesn't normally reach.....yes I'm grasping and haven't yet hooked up a pressure gauge to test this theory and I'm pretty sure the factory gauge would not be sensitive enough to reflect any change.

 

[Mooseman]

I've seen the inside of this engine way more than anybody should but all I have is theories as to why this happens. Maybe the valve lifter is clogged or defective and the vacuum helps pull the oil into it to quiet it down. Could be low oil pressure but not low enough to trigger the low oil pressure switch.

I would check the oil pressure with a real gauge because we all know that the one in the dash is fake. If that checks out, I would try a flush. Something to use long term would be to replace one or two quarts of oil with tranny fluid at the next oil change. The detergents in the ATF could clean things out in the long term. This is an old hot rodder trick.

 

[jimb442]

Thanks Moose. I've done a flush and even plugged the hose several times during the flush to (in theory) get the flush to reach the problem area. As I said in a previous post, the ticking has probably improved a bit but is still there.
I think if I feel up to it, next summer I will get down to the lifters and check and replace.

Have you ever heard of this type of noise coming from the Variable Timing Solenoid?

I think I read that on some forum somewhere....

 

[Mooseman]

No, never heard of that but anything is possible. Worth a look but you said that the noise is coming from the rear of the engine.

 

[oleblue02]

Have you tried marvel mystery oil or Lucas heavy oil stabilizer?

 

[gmcman]

The only lash adjusters I wasn't able to clean were the 8 on cyl 5&6 and the forward most on the exhaust side of cyl #1.

I will go back pretty soon and get all of them now that I have the correct tool.

 

[jimb442]

thanks gmcman....good to know. Moose, pretty sure the sound is right near the front (don't recall saying the back) and if I had to choose a side, perhaps slightly more from the driver side of the head?
Oleblue, haven't tried either of those but have tried seafoam and then a flush product from NAPA. I have heard some good reports on the MMO so maybe I should give it a try. Have you personally had success using it for this ticking problem?

I was thinking I may try one more flush at the next oil change just to see if it helps. I maybe recall a couple contributors in this or another forum saying they did more than one flush to clear the problem? So, for a few extra dollars I would be foolish at the next oil change not to give it one more shot.

 

[Mooseman]

Sorry about the mixup with KickAss' post where his was at the rear.

 

[Trace Roro]

Well, GMCMAN did the clean up kill the valve train noise?

I too have a tick ticking around in there but changed my exhaust VVC yesterday. Ill give her a stethoscope listen this weekend.

 

[Lynn]

Hi guys, new to the forum, not sure I am qualified to offer advice but I will, don't put too much in the noise going away or diminishing when putting the motor under vacuum. A law of Physics is that noise does not travel in a vacuum. The test with vacuum will tell if its an internal problem or external but other than that it may be a red hearing.

 

[m.mcmillen]

If you're wanting to see some pictures of the inside of this engine go here http://gmtnation.com/forums/threads/4-2-engine-rebuild.16080/

I chased my knocking noise for a few months. I checked it with a stethoscope and thought I had narrowed it down to lash adjusters. I found a few that were collapsed. So, I went ahead and changed all 24 of them. No help.

I checked my oil pressure with a gauge and found that it was excellent so that pretty much ruled out a bearing or pump problem. The noise on mine also went away when the PCV hose was blocked off.

I drove my TB all summer and made several 3 hour trips up North to go fishing. No problems with performance or MPG.

Back in September, the noise got noticeably louder so I pulled the engine and tore it down. I found 3 scuffed pistons. I suppose the previous owner ran it hot at some point.

Now, I'm giving it a rebuild and I'm almost done with that. I hope to have it running in the next week or so.

 

[OMVIJOCA]

Hi McMillen. I don't post much but have repaired several transmissions on these cars and also did a 4.2L engine swap. I tend to by these cars cheap. I repair them and then usually one of my 7 kids gets them.

My ticking problem is driving me insane on the 2004 Envoy 4.2L. I've tried all the flushed, next is replacing the lifters. I've ordered a special tool so I don't have to remove the camshafts. I'll report on my experience of this elusive ticking. However, I'm curious, did the replacement of scuffed pistons resolve your issue?

Thanks!

 

[m.mcmillen]

Yes, the pistons were the culprit. It purrs like a kitten now.

 

[OMVIJOCA]

McMillen, Thank you for the reply. Getting a replacement engine is where I may be headed next. With this news and all the troubleshooting so far: I may get brave and put in a 5.3L V-8 instead. That is a spring project and will post the update. Again, thanks!

 

[OMVIJOCA]

Also,
based on your work in troubleshooting and rebuilding your engine... would you say the scuffed pistons are the source of "piston slap" that many folks have talked about?

 

[Duck]

Hi McMillen. I don't post much but have repaired several transmissions on these cars and also did a 4.2L engine swap. I tend to by these cars cheap. I repair them and then usually one of my 7 kids gets them.

My ticking problem is driving me insane on the 2004 Envoy 4.2L. I've tried all the flushed, next is replacing the lifters. I've ordered a special tool so I don't have to remove the camshafts. I'll report on my experience of this elusive ticking. However, I'm curious, did the replacement of scuffed pistons resolve your issue?

Thanks!

I would like to know if you could tell me the part number and we've got the part to change the lifter the tool

 

[mrrsm]

Welcome to GMT Nation...

If you are looking for the New and OEM Engine Rebuild Components and Fasteners for the Overhaul of the GM Atlas 4.2L I-6 Engine. Please visit this Link to my “Flickr-Bucket”. If you look around at the other albums… I have memorialized the Engine Dis-Assembly there as well

https://www.flickr.com/photos/126111508@N07/albums/72157671179967478

I have attached some images of the Atlas 4.2L OEM ACDelco Rocker Arm AKA 'Roller Cam Follower' as well as a shot of one of the diminutive Valve Lifters with the Part Number you require... and images of the K&M R&R Tool as well. While you are in there... Don't miss the chance of obtaining and installing Brand New Valve Cover "O" Ring Style Gaskets while the opportunity presents itself:

Note:

The Two K&M Screw Fasteners are applied into the adjacent threaded holes designated for the Coil On Plug (COP) Hold Down Bolts. Do NOT Over Tighten those Fasteners. If you have any questions about How to Use Specialty GM Tools... Use this next Link to open a GM Video Training Film Index and look up EN-47945 and click on the Blue Text Name... A window will open and an Instructional Training Video will play precisely what you need to know:

https://gmtoolorg.service-solutions.com/Media/Common/Documents/GM-tool-org-videos%20(2).pdf

 

[DigitalSamurai]

The only lash adjusters I wasn't able to clean were the 8 on cyl 5&6 and the forward most on the exhaust side of cyl #1.

I will go back pretty soon and get all of them now that I have the correct tool.

Mine is almost dead silent now when running and hot, it goes through stages and sometimes after a minute or 2 of startup when cold it will make a noise but I think this is my exhaust manifold as the last bolt is broken.

Either way, I pulled my valve cover, and most all the lifters had some type of buildup in them. I cleaned a bunch with mineral spirits, kerosene, and while trying to free them there was dark fluid coming out of the bleed hole.

I'm not sure exactly but I would suspect they need to stay pumped up, but these were basically locked into the "pumped" position. I needed pliers, and solution just to get them to retract and then I could work them against the spring inside to clean them out.

They are pricey to replace and you need a special tool.

Can you post a video of the noise?

When you used the Kent Moore tool to compress the valve spring to remove the rocker arm, did you also need to use a compressor to keep the valve pushed up? I need to replace some lash adjusters on my 2004 Trailblazer and it looks like you don't need a compressor to force the valve to stay up while the spring is compressed, but wanted to confirm first.

 

[gmcman]

When you used the Kent Moore tool to compress the valve spring to remove the rocker arm, did you also need to use a compressor to keep the valve pushed up? I need to replace some lash adjusters on my 2004 Trailblazer and it looks like you don't need a compressor to force the valve to stay up while the spring is compressed, but wanted to confirm first.

I believe you're thinking old school cam and push rods.

The 4.2 has overhead cams and the lash adjusters keep the...I believe...followers or rockers with zero clearance.

When you use the Kent Moore tool, it's holding the valves open and just releasing pressure from from the rest of the mechanism...you won't drop a valve.

Also, don't use the tool to compress the spring. You need to use a bump starter with the fuel system de-energized and allow the camshaft to open the valve.

Then place the tool over the valve only finger tightening the bolts. At that point you use the bump starter again and rotate the cam lobe away from the valve rocker releasing the rocker.

Once the rocker is out of the way you can lift the lash adjuster out of its bore.

With 2 people having a good rhythm going it takes about an hour and a half.

 

[gmcman]

Here's a few pics of mine when I changed them.

The rocker doesn't ride on the stem, but the keeper.

The rocker needs to be removed to access the lash adjuster...small curved needle nose pliers work excellent.

 

[DigitalSamurai]

I believe you're thinking old school cam and push rods.

The 4.2 has overhead cams and the lash adjusters keep the...I believe...followers or rockers with zero clearance.

When you use the Kent Moore tool, it's holding the valves open and just releasing pressure from from the rest of the mechanism...you won't drop a valve.

Also, don't use the tool to compress the spring. You need to use a bump starter with the fuel system de-energized and allow the camshaft to open the valve.

Then place the tool over the valve only finger tightening the bolts. At that point you use the bump starter again and rotate the cam lobe away from the valve rocker releasing the rocker.

Once the rocker is out of the way you can lift the lash adjuster out of its bore.

With 2 people having a good rhythm going it takes about an hour and a half.

Thanks. I figured the keepers are still on when the spring is compressed. I was overthinking it (old school is correct ;>))If I understand you correctly, the the cam lobe is pressed against the spring to compress it to open the valve, then finger tighten the tool on the spring and move the cam lobe away to release the rocker to get at the lash adjuster? I found the location by using a stethoscope and it's on the second cylinder on the exhaust side.