'02 Impala 3.4l 103K: Loud(er) Upper Engine Clicking

'02 Impala 3.4l 103K: Loud(er) Upper Engine Clicking

First noticed the engine clicking last April when the car had about 91k miles on it. At that time - and up until yesterday, I guess, it was only on startup on cold mornings, so I kept an eye on it but didn't really do anything about it.

Today, the noise is louder and it's not going away as the engine warms up - it's staying just as loud. The only thing that changes is the periodicity is slowing down as the engine slows down. It's definitely coming from the very top of the engine, and I'm guessing it's piston slap or lifter noise. I just took the car on a relatively short 170 mile roundtrip this weekend and didn't notice this noise, so I think it just got loud today. I also just changed the oil 1k miles ago, and the dipstick is right up into the cross-hatched area with good color (golden-brown), so that's not it. I always change the oil every 3k miles, so it's not from maintenance neglect. I'm guessing that this is related to the manifold intake leak, which I'm sure the car has, but the leak is very small.

The question is: should I pour in some SeaFoam right now? Does that stuff work? Is there a penalty for using this stuff? I'd like to buy a little time so I can decide what I'm going to do next.

If the noise is coming from the top of the engine I would bet that its the rockers or the pushrods. I dont think you would hear the piston slap on the top. You could always check to make sure you dont have a loose lifter or two.

If you take off enough components to check the tightness of the rocker towers, you might as well do the UIM/LIM gaskets. When you do the gaskets you will then be able to inspect all rockers and pushrods. Roll the pushrods on a mirror or other very flat surface. If there is <i>any</i> that are even the slightest bent replace them all.

Personally I would say do the gasket fix as soon as possible if you know it has a leak. Even a small leak left unchecked or fixed can cause you lots more grief in the end. I was lucky and my leak was external but I still got it taken care of with in two weeks of noticing antifreeze on the ground. If your leak isnt external you are going to have major problems down the road if you dont do it now ;)

Surrender,

Thanks for your reply. I know you're right that I should change out those gaskets. I've had the replacements (Felpro full set) for quite a while now waiting for a good time to do it. I was going to do it over the Christmas break, but I got dragged off on a vacation.

Can I continue driving the car until the weekend? It would only be 30-40 miles per day. I was thinking of using either the Seafoam (crankcase only) or Marvel Mystery Oil in the meantime to get me there.

By the way, what exactly is the "lifter" component? It's not the pushrod or rocker arms, right? I thought the cam moved the pushrods which in turn moved the rocker arms? Are the lifters at the bottom of the pushrods?

Lifters are different than rockers. The lifters I do believe are under the pushrods over the valves. (anyone with more experience, please jump in) Does the tapping increase in volume the harder you push the engine, like in passing mode?

Here is some helpful info I found in a reply BNaylor made to my intake gasket post that may or may not help you diagnose piston slap...

"...The lifters may tick as well. This is not to be confused with the sounds of valves contacting the pistons; lifter tick is a softer noise that fades as the engine warms up and the oil thins. A valve contacting a piston is a much sharper noise that most likely can be felt by touching a valve cover. It will not go away as the engine warms up and will most likely be accompanied by a rough idle..." - Adam Riggs, D-tips.com

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I have done a bunch of looking and found that a noisy valve train is quite common concerning our engines, especially the higher the mileage. When I got my car almost three years ago (109k) there was virtually no tapping noise heard. Now the car is close to 128K and from time to time I notice a tapping upon starting the car (louder when its cold) but it always quiets down. I am not sure whether the lifters are adjustable in the 3.4L (again, more experienced member care to chime in?)

Depending on where you live, you could try a thicker oil, at least during summer months. Remember, the older your engine gets, the more it has worn and you need to fill those worn spots with thicker oil otherwise you get more and more wearing faster and faster till a breakage occurs. I think that there is also a ceramic additive you can buy too. Thats about it besides having a lifter/valve job done. BTW I have run Castrol Syntec 5W-30 since my first oil change after buying the car. I am thinking about going to a 10W blend for the summer to quiet any lifter noise. Guaranteed it will still be synthetic though.

The 3400 is known for eating camshafts and washes the cam bearings out.The block is automatically junk after this happens and I have seen in many 3100s and 3400s do this.The last one was out of a 1999 Venture Minivan.If you think it is the camshaft because is hollow in the center,you are wrong.It is the block when it was casted in China,the journals are casted offset and GM put in cheap cam bearings.Jasper,a top of the line reman engine company fixes this by alighn boring the cam journals and puts in upgraded cam bearings.I was told this by a Jasper rep that I know since my father is a Jasper dealer.The rep brought in a part of a broken cam out of a 3100 as a sample and explained this.

The loud clicking went away. Only happened that one day. Now it sounds really good - purring like a kitten. Nonetheless, today I poured 8 oz of SeaFoam into the crankcase, let the engine heat up until the fans came on, then shut it off. I'm letting it sit overnight, then I'll warm it up again tomorrow and change the oil. DID notice (for the first time), two thin streams of coolant leaking out of the block along the V-seal behind the power steering pump/water pump area. With the car running, I could see coolant bubbling out every 30 seconds or so. Not a major deluge, but very noticeable. Also might be leaking on the throttle body side - I see some liquidy leakage there too, but it's harder to verify the exact volume.

Also made up my mind that I will attempt to tackle the intake gasket replacement myself. Surrender - I know you did yours. I'd appreciate it if you could be "on-call" while I do mine. I'll probably be starting on the 12th, but possibly even as early as the 10th. I think I'll be replacing all the lifters in addition to the gaskets, so there's added complexity for me (a non-mechanic). AutoZone has replacements for $8.99 by Melling (?). The dealer wants something like $24/lifter! I think I'm going to roll the dice with the AutoZone parts. I'll probably have to open the thing up a 2nd time to fix something I did wrong anyway...

Here's my list of stuff I already have or need to get:

1.) Felpro gasket (metal frame) set with the upper, lower, and bypass O-ring included.
2.) EGR gasket(s) - are there TWO of them (above and below plenum)?
3.) Fine grit emory cloth
4.) Black sensor-safe RTV sealant (for a caulking gun?)
5.) OEM T-stat
6.) Oil pump O-ring
7.) Spark plugs (probably AC Delco Iridiums?? - Do I have to get these at the dealer or are they available in stores?)
8.) Spark plug wires (probably OEM)
9.) PCV Valve - maybe.
10.) BLUE threadlocker (RED is too strong)
11.) Throttle body cleaner (to clean inside of T/B)
12.) 1/4 drive extension and socket for diagonal manifold bolts (what socket size???)
13.) engine degreaser (clean engine after buttoning up)
14.) Dielectric grease (spark plug boots and/or coolant contacted parts)
15.) Sspecial tool to remove push rods w/o touching rocker arm nuts (rental?, if not online for ~$14)
16.) Parts tray/table (just for me, I'm working outside in a driveway w/o roof overhead)
17.) Flourescent double-halogen light on stand + trouble light (just for me, I may end up working after dark)
18.) Special tool to disconnect the fuel lines from the fuel rails???

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Also, I know that I need to follow the special torquing sequence on the manifold bolts and that it's very important to make sure all the pushrods go back in their original locations (so push the rods through a marked carboard box to keep them straight).

Any other advice anyone wants to add? How about the technique for releasing some of those plastic connectors? Is there a special tool to handle all of them? It seems like I break these things about 50% of the time either because I misjudge how they are supposed to release, or I'm doing it right but the plastic is so dried out it just crumbles. I've had to put nylon ties around some of them (VSS on my Taurus) in the past to ensure that they stay connected.

Colt, I saw your icon was green when I loaded the page but by the time I logged in you had already "left". I will help out as much as possible but I am not a mechanic, just mechanicaly inclined as you seem to be. This is def a do it yourself job if you are organized. Again you seem to be. Here are the things I can help you with your list.

2. There is only one EGR gasket. 7-8 bucks

3. Make sure you use a very high gain emory cloth. I didn't use any. I used a razor and cleaner to make sure all mounting surfaces were clean. The T/B cleaner should be good enough. Remember, the parts you are cleaning are aluminum so you dont want to cause any scratches. The gasket wont seal properly and you will develop a vaccum leak.

7. I put Iridium in mine. 41-101 AC Delco for around 7 a piece.

12. 10mm for intake bolts from what I remember.

15. I loosened the rockers just enough to take the pushrods out by hand. No special tool used.

18. Fuel rails... there is a shrader valve on back fuel rail by alt. Put a rag over it and depress to relieve fuel pressure. 9/16 SAE on back rail and No. 27 torx for front rail. Make sure to remove the fuel sensor retaining clip from the fuel rail and keep it with the torx bolt. I had a hell of a time finding mine as I left it on the rail. Well I didnt take the rails off the lower intake and when I was cleaning it, the clip fell off. Took over two hours and a trip to the parts store to find out its a GM specific part.

As far as the plastic connectors go, there are a few different kinds. I used my fingers and a flat screwdriver for most. Just make sure that you put the clips that hold the ends together back in the harness as to not lose them.

If you have access to a digital camera, I highly advise taking pictures of the tear down so you can reference them on the rebuild if you need to. If I or others are not around, check this site as its VERY VALUABLE to someone tackling this job. They put all the technical stuff into words the average joe can understand.

BNaylors link (http://d-tips.com/General/Articles/article.aspx?id=/free/How%20to/Chevrolet%203.4%20intake%20manifold%20Gasket/art10.art) from my original post.

Surrender,

Yeah, I'm not a mechanic either - just a software guy who seems to like challenges. What I'm not crazy about is the anxiety I always seem to feel along the way - and I'm sure I'll be feeling it on this project.

So you just loosened the rocker bolts to get the pushrods out? I'd rather not do that because then I assume you have to re-torque them to spec. I could see myself missing one of them and having a problem later.

Thanks for the fuel sensor clip advice. I'll be looking for that one. That sounds like something that would happen to me - losing it, then having to run around looking for a replacement.

I've got a digital camera and I expect to be using it. Hope the pictures are usable. It's not an inexpensive camera, but it needs a lot of light. Indoor pictures are pretty useless, although I really haven't re-tried indoor shots since downloading the manufacturer's firmware patch which is supposed to correct the problem.

I printed out the dtips repair thread (and I've read it at least three times now). It's really good, but there are still gaps in it for people like me. Maybe I can create a true A-to-Z version for us non-mechanics...

The intake bolts,10mm have to be replaced and Dorman products includes new intake bolts with their intake gasket kit which the intake gaskets are metal.Dorman is the only one that does this that addresses GM's tsb 03-06-01-010B,if you want the part number and here it is: 615-205. Here is Dorman's website: www.DormanProducts.com

When I did mine, I used the same bolts. I cleaned them and chased the threads to remove any of the gunk. I havent had any problems so far. As far as the rockers/pushrods, I tightened them to spec as per my haynes manual.

I was lucky and borrowed a friends in/lb torque wrench as some of the specs are in inches, not feet and the one I checked out at the parts store didnt go low enough.

After doing all my research, I made a list in one of those pocket notebooks of everything I had to take off and in what order, then just reversed it. This included everything from the battery down to cleaning parts after removed. (I removed everything, covered engine with table cloth and then cleaned all the parts at once.

Remember the small cardboard box with 12 holes for the pushrods. Label front and back and put an arrow on the belt side, then just put em in. And weather you have total confidence in yourself or not, I think you are going to be just fine man.

GM says to put in new bolts and I do not torque them,I will tell you why I don't.The problem with torqueing them is most people overtorque them and do the job all over again.I know one owner of a Carquest parts store that goes through this from customers including the guy who comes in to check on parts that stock orders.I run them down easily with a 3/8" impact,hand tighten them and have not had one come back ever since so far.

wafrederick:

I bought the Felpro gaskets last year. They're on a metal frame, too - but no bolts. At the end of last year after I bought the Felpros and had 2nd thoughts about using them because GM had put out yet another set of gaskets, I decided to check out these new gaskets at the local dealer. They looked pretty flimsy to me - kind of like those cheap plastic clothes hangers kids clothes are sold on. BUT - GM decided to include the bolts with the gaskets. I think the kit was $40something bucks. Not bad, but the Felpro gaskets look far more substantial to me.

Surrender:

I was thinking I'd be washing down the threads with brake cleaner or some kind of solvent (WD-40?). How do you "chase" threads? Is this some kind of special technique? As far as the torque wrench goes, I think my Craftsman "click-style" wrench will work. I had bought a ft-lbs wrench (also click-style) a long time ago, but quickly found out it was useless because it could never go low enough for anything I needed to torque down (eg: pan bolts). Finally bought the in-lbs wrench a year or so ago. I think it gets down to something like 5 in-lbs?? Works pretty good, too. I think I paid about $80 at Sears for it.

I made the same list of parts to remove like you did, but I used the Chevy Shop Manual to make it. I don't know how useful it'll be because I know it calls for removal of stuff that probably isn't necessary. Took a while to make this list because the Manual procedures are modular and "nested". A lot of page-flipping to expand it all out into a linear procedure. I think I know enough now to make a list off the top of my head - which is probably a lot more useful. Probably the most important thing I haven't even done yet, however, is to record the torque specs for all the bolts to be removed. And you know what I wish they'd specify in these manuals is THE DARN BOLT HEAD OR SOCKET SIZE!!! I need to buy some kind of tool to measure bolt heads so that when I need to buy the corresponding socket, I know exactly what I'm looking for. I buy tools as I need them and use a ruler to estimate the bolt head size. This method is just not accurate enough because of the fine line between SAE and metric.

Just change the oil on my Impala after running the SeaFoam through the oil. Nothing spectacular to report. No smoking, no gunk in the oil. Only got a little over 4Qts out - even with the 8 oz of SeaFoam added, so the coolant isn't leaching into the oil, I think it's the other way around. And the external leak is very obvious now near the PS pump - bubbling and streaming out (slowly), but the engine is VERY quiet. Sounds like new, actually. Maybe it knows it's about to be ripped apart by an amateur...

wafrederick:

But if you don't know exactly how much torque you're putting on each bolt, how do you know if you're not slightly torquing one more (or less) than the others? Now, I DID use your method once when I took down my tranny pan on my Impala - but it was because my torque wrench didn't go low enough to be useful. I drew a diagram of the pan, numbered all the boltheads on the diagram, then proceeded to turn them ever so carefully in a pre-determined criss-cross pattern. I would bet that all 20-some-odd bolts got torqued very close to the same amount, and it never leaked a drop, but that's a tranny pan. I don't know if I'd trust that method way down inside an engine! I'd hate to get just one bolt wrong and have to rip the whole thing open again just for that.

Maybe that method works for you because you have "perfect torque" - like some musical people have "perfect pitch"...

Ok, to clarify, I didnt use a thread chaser to "chase" the threads. I used an in-hole wire brush for a drill. Here is a picture of a hand set (http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200349797_200349797). A quick question, have you gotten a manual for reference?? I highly advise it! (haynes 24048) If not here are the torque specs that you will need... took a bit to find my manual.

Your Craftsman torque wrench is perfect.

upper intake bolts
18 ft/lbs

lower intake bolts
step 1. 89 in/lbs
step 2. 115 in/lbs (then go up to 18 ft/lbs as stated in the revised procedure) Your fel-pro set should have the revised specs as well ;)

rocker arm bolts
step 1. 168 in/lbs
step 2. rotate additional 30 degrees

valve cover to cyl. head bolts
89 in/lbs

For upper intake there is no real sequence for loosening or tightening. Just start from the center and go out in circle. Loosen all intake bolts 1/4 turn at a time till finger loose. This keeps the intake from warping. Follow this pic for the lower bolts (to loosen bolts reverse order)


http://a801.ac-images.myspacecdn.com/images01/113/l_3ec488ff265b5b8bb217ffea4d422590.jpg

Feel free to email me if you need to.

Surrender - sorry you went to all that trouble. Yes - I've got both the Helm Factory manuals and the Haynes manual. When I said I needed to record the torque specs for the bolts I meant I just needed to look them up in BOTH manuals and record them on my procedure so that I wouldn't have to touch the manuals during the job. But thanks, you just saved me the trouble.

Bought that pushrod tool from Lisle this week. Paid $19 locally - which is as good as I would've done buying it on the Web. AutoZone and Advance didn't carry it and wouldn't order it, however, so an independent ordered it for me and had it (unbelievably) the next morning!

Also picked up some #220 grit emory cloth. That was the highest number sold, but yesterday while I was looking at caulking guns, I noticed sandpaper with a grit number over 400! It didn't say "emory" on it, but should I use this instead, or is the #220 OK. #220 seems to have some teeth to it when I run my fingers across it.

Still no engine clicking since running the Seafoam through the oil and changing the oil. Sounds very quiet.

Planning on starting this Thursday if weather permits.