Maxima-Ness

Okay, so for the second time today, ive been told by a mechanic that my ticking noise when the engine is running is caused by "dirty lifters". I know there has to be some sort of chemical additive to clean them or some belabored process of cleaning them, apart from tearing the engine apart. I always use 93 octane and change my oil (Amsoil) as scheduled. Anyway, with 110000 miles on it, im sure this was unavoidable. Any suggestions on how to fix this?

Deckdout2

iTrader: (151)

Seafoam fixes everything.

/thread

Maxima-Ness

No it doesnt. Last time I used seafoam (as directed from org members and instructions on bottle) My o2 sensors had to be replaced. Luckily I got them replaced under warranty, but I do not want to go through that again.

/next...

Deckdout2

iTrader: (151)

Really? That hasn't happened to me yet. It suppose to go through and clean out all the carbon buildup internally. I've done it like 8 times since I've had the car and no o2's have gone out on me yet. Which vacuum hose did you use to feed it through? I used the one coming off the black canister attached to the firewall and the other end is attached to the upper manifold. That's odd, maybe someone else has had that issue.

You could always spray a few shots of nitrous through it. That definately cleaned up my internals when I had the bottle.

/b/

Just an FYI: I'm at 111k, and have been using the following, NO PROBLEMS AT ALL:

Seaform before oil change
Auto RX additive upon oil change
Chevron Techron every 5k

For me, this has worked wonders. Give the techron a shot upon next refill.

nismology

iTrader: (8)

VQ's don't have lifters.

Maxima-Ness

Interesting to find that out. So what do you think it could be?

Also, as Im sure Im going to need some specs to show for it, where do I find tech specs on what they do have? Im no mechanic and have no idea what to say to this now. This is the first ive heard that VQ's dont have lifters. Ive even done searches on the org and nobody brought this up once.

Professor

iTrader: (4)

They have solid lifters, or hydraulic , similar.



cam rides on top of these, the vales are under them

nismology

iTrader: (8)

That is not a lifter, it's a bucket tappet.


In any case, there's nothing in the VQ's valvetrain that would tick like a faulty lifter would.

P. Samson

This is old ground again. With the normal valve lash (there has to be clearance with the Maxi's solid lifters to ensure that the valve can seat on the valve seat, otherwise you will burn the valve) you shouldn't really hear much "ticking", maybe only very light ticking. But if this clearance increases due to wear of the cam lobe, or the lifter bucket shim (Gen. 5) or the bucket itself (Gen. 5.5), or the valve is sticking in the valve guide due to coke/carbon, or excessive deposits on the valve/valve seat that don't allow the valve to fully seat, then you can get excessive valve noise like a "heavy" ticking. The wear can be caused by dirty, contaminated oil, or oil starvation etc. Just change your oil frequently enough and maintain the correct oil level and ensure that the crankcase vent and PCV valve/hose are clear and working, which will help to prevent valve train issues.

nismology

iTrader: (8)

Incorrect valve lash can cause problems in any engine, regardless of the valvetrain setup. The point is, VQ-equipped maximas don't have "lifters" that can tick the way hydraulic lifters can.

NisTech

you can pull the cover off and follow manual on how to check bucket to cam lobe clearance. then you might want to check for actual wear on cam and caps. for that you will have to use plasti gauge. (harder and more labour involved)

Maxima-Ness

thanks for all the replies!

Sounds like im going to have fun with this one. Ill take it by the mechanic on Tuesday to see whats up and hear what he has to say. Im not taking it to the stealership; theyd probably tell me I need a new engine or something.

So if its not what I thought it was, even though thats the noise it was referred to, what could it be? Its not like I dog the hell out of the engine, and its not driving rough or showing any lack of power, it just ticks at idle and just doesnt sound right.

feel free to continue discussing...

jasonmax

iTrader: (2)

it also can be noisy injectors.

Maxima-Ness

didnt think about that one. Ill write that on the list of "maybe's"

NisTech

get a long screwdriver and place it on each part of the engine and place the ear at the end of it and listen to where the noise is loudest.
that will eliminate a lot of the guessing.

KRRZ350

iTrader: (29)

No amount of seafoam is going to fix what's wrong with this picture............

P. Samson

Not a great photo but it looks like the valve stem contact surface of the bucket is worn. What does the end of the valve stem look like? Could this be a material hardness (case hardening?) issue, or a lubrication (lack of) issue? Any sign of wear on the bucket cam lobe contact surface where you'd kind of expect it first? Even though there have been quite a few "hashy" sounding 3.5s on this forum, I hope that this is not really that common.

KRRZ350

iTrader: (29)

Yes, you see correct, don't have any better photo's but the closest one is junk, the middle one is perfect, and the farthest one is ultra-junk. Cool thing is the valve stem suffers no damage. Uncool thing is it is caused by a lack of lubrication, happens on the rear bank exhaust ones first. To fix, you just grab the number from the underside and replace it with the same size, double check clearance but it has always been spot on: ie nothing else wears not even a thousandth's. More bad news though is that the lack of lubrication usually stems from a bad oil consumption problem that let it get 1.5-2 qt's low and possibly brought up to redline low like that.

KRRZ350

iTrader: (29)

When the bucket tappet get's mashed down 30 thousandths it sure sounds similiar to one.

jasonmax

iTrader: (2)

how hard to change them? can they be changed during the replacement of the valve covers?

nismology

iTrader: (8)

Excessive valve lash can cause noise regardless of the valvetrain setup. This does not mean that the VQ has hydraulic lifters that can fail and tick as a result of the failure mode specific to these types of valve actuators. I just wanted to clarify that fact.

But your findings regarding bucket failures are interesting indeed. Are the cams junk as a result or are they reusable?

P. Samson

This is an extremely good find (and info) by KRRZ350. A number of VQ35 videos have been presented for troubleshooting purposes on this forum where the engine is running at idle and/or accelerated and is making a continuous noise that is often attributed by some members to either the VTC sprockets or to the primary timing chain (tensioner issue). Very often, to me anyway, the noise seemed to be more like the noise generated by excessive valve clearances. I suggest that if you have a VQ35 (or a VQ30 for that matter) that is making the noise like in the video below (that is not at startup only), but a continuous "louder than normal" ticking/clicking/tapping sound from the top of the head area, then I would remove the camshaft covers and carry out a valve clearance check. This would be an example of the kind of noise that I'm taking about: http://s446.photobucket.com/albums/q...VIDEO00041.flv

zero2sixtyZ

iTrader: (30)

I'm pretty sure I have the same noise. KRRZ350 checked my car for the noise, and it seems to be the buckets since he has encountered that problem on another VQ35. I'll try to get a video of my noise.

jasonmax

iTrader: (2)

mines been making noise on the valve cover area since I bought. are they hard to replace?
vid.
http://www.youtube.com/watch?v=UzwiMWC_9EQ

02bluemaximase

I HAVE A VERY SIMILAR RATTLE NOISE - MINE IS VERY LOUD, THOUGHT IT WAS A STUCK LIFTER

P. Samson

Normally the lifter sound and the actual clearances don't change that much over the service life of these engines. If you determine that you have excessive valve clearance noise, which is definitely not normal for these engines, the repair may be a PITA. First thing to do is to remove the camshaft cover(s) and accomplish a valve clearance check and see what you've got. Running an engine low on oil or run with no/low oil pressure as mentioned by KZZR350, can cause major wear issues particularly for the cam lobes, the cam lobe contact areas of the buckets (VQ30 shims) and the valve stem contact area of the bucket. If the wear has occurred on anything other than the shims (on a VQ30), then unfortunately removal of the camshaft(s) will be required.

KRRZ350

iTrader: (29)

So far on all of them no cam lobe's were worn/damaged at all. Replacing just the tappet with an identical sized one brought the clearance's back right on the money. i wouldn't worry about cams as much as I would the initial reason it was run low/no oil pressure there.

Yes, Sampson is correct, checking the valve lash is the best way to be 100%. I've just heard it a few times and now can identify it right away, yet even I would still check the clearance before going any further.

nismology

iTrader: (8)

starbai

Sorry for bumping such an old thread but instead of starting new I'm trying to search to see what may help me.

I've got an 02 Pathfinder with the VQ35DE.
here is a vid of my noise:


Do you guys think it could be buckets? I'm at my wits end trying to figure out how to attack this.

If I pull the valve covers off to check the clearances, do I have to replace the valve cover gaskets when putting it back together? Or could I theoretically reuse what I have till I figure this out?

The parts are like $20 a piece and I'm told the tool needed to adjust the valves is like $380. On top of parts makes this seem like it may not be worth fixing?

starbai

Well no help here but since I posted this I figured i'd post an update in case anyone finds this thread through a search.

After measuring the valve clearances there were at least 7 that were off quite a bit. Ironically all on the exhaust side of both banks. So pulled the camshafts, got the valve lifter buckets out and measured them and it was clear that the little nipples inside of the ones that were off were either crushed or half way dented in... clearly contributing to them being off and probably causing quite a bit of my ticking troubles. Got 7 ordered and picking them up today.

With the front timing chain cover off I noticed that the main tensioner was actually doing okay, and was applying a good amount of tension on the guide. But the guide itself was very loose on the bottom. You could easily move it with your finger even though pressure was being applied to the chain. Elsewhere, the chain guides (more to the right) you could easily flick the chain around in between the guides and if i flicked it around fast enough it was very similar to the noise that I was hearing when it ran (albeit much more slowly)... so i'm fairly confident that that was contributing to my noise issues.

Child_uv_KoRn

iTrader: (7)

Exhaust side runs dry 1st, so the buckets are wrecked. Someone ran it out of oil before you.

MaxVQ5spd

iTrader: (1)

I have a ticking from the back bank. Ran my 2002 Maxima black/black 6spd HLSD that I've babied all it's life low on oil....so could really kick myself. My noise is not nearly as bad as what you have in your video, but enough to make me want to repair. From what I'm reading it sounds like you have to remove the cams to replace the bucket lifters....correct?

Juan Fe Palacio

they actually do... they have hydraulic lifters

slvr2KSE5

You're very late to the party and no the vq does not.