# Tap/Rattle WTF?



## 4thGenTinkerer (Nov 1, 2009)

So I noticed a tapping in the upper end of my engine this morning. It seems to be coming from either the timing cover or the cylinder head closest to the firewall. It sounds like rattle/tapping noise as the RPMs fall from about a 3k rev. (cant tell cuz im under the hood workin the throttle) After the engine warms up it seems less pronounced but is still there. So im guessing i should start by checking the timing chain tensioners or the valve clearance. Maybe camshaft journal clearance? camshaft runout? Sticky lifter? I have another complete head, maybe just swap heads. My knock sensor is good and i only run hi test and NGK plugs. Anybody want to point me in the right direction before i start working on somthing that isnt tapping/rattling lol.


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## stillentuned96maxima (Feb 17, 2010)

Well not to try and scare you but this happened to me about 5000 miles ago and then the knock got worse and worse. and im pretty sure it has to do with a lifter or rocker arm comming loose but on this last friday, my engine blew up and leaked oil all over the highway, and all the oil came out by the rear vavle cover by the fire wall on my 96 maxima. So what i would do is have it checked out and make sure thats not the case or it could be a timing chain or a vavle sticking. please lemme know if i helped u any. Thanks


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## 4thGenTinkerer (Nov 1, 2009)

Im sorry to hear about your engine. However your first mistake was to keep driving it. If you hear somthing rattling STOP. 3.0VQ's dont have rocker arms. They have hydraulic lifters. So what caused your motor to blow? Did you have it repaired? I dont intend to drive mine untill I am able to diagnose and repair the rattling. Im hoping for someone who has had the same problem to point me in the right direction. I dont want to pull the head, timing cover, intake mani, etc if i just have to do somthing stupid like bleed the power steering pump.


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## JNCoRacer (Apr 18, 2003)

Sounds a lot like the typical timing chain rattle on our motors.


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## stillentuned96maxima (Feb 17, 2010)

yah ur right, it was dumb on my part for driving it like that and thank you for letting me know theyr hydrolic lifters because that is something I didn't know. However, I don't know what exactly the cause of the engine blowing is yet. I have plans s this summer to hopefully tear apart the motor and repair the cause.


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## 4thGenTinkerer (Nov 1, 2009)

JNCoRacer said:


> Sounds a lot like the typical timing chain rattle on our motors.


Care to elaborate? Like the tensioners? or the chain? All three or just the primary? 

Its sounding pretty bad. It taps/rattles both at an idle and when i give it gas. Although it seems to subside somewhat as the engine comes up to temp. and at about 3500-4kRPMs. Will the timing chains and tensioners make that kind of noise? 

Thanks for your input guys, and welcome to the forum stillintuned96maxima.


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## JNCoRacer (Apr 18, 2003)

Yes, just the tensioners. The chain should be fine.

Would you be able to record the sound and post it here?

Another thing, is your AC on when you hear the noise? My AC compressor makes a "knocking" noise when the AC clutch is engaged. Its actually louder and lower-toned than my timing chain slap.


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## 4thGenTinkerer (Nov 1, 2009)

The Ac is definitly off as well as the defrost. I think i could record the event. I will make a hi-res vid in the morning and see about posting it here. If i prove to be too tech challenged i will upload it to youtube and post the link. Would I have to pull the timing cover to get to the tensioners or can i get to them through those little four bolt covers? Thanks again JNCoRacer, You have givin me some great advice in the past. looking forward to your opinon.


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## JNCoRacer (Apr 18, 2003)

I just had to ask about the AC compressor. I had to take a look around my engine bay when I first heard it.
The tensioner you can get to from the cover, its the guide at the top that has to have the whole timing chain cover removed to get to. It'd be easier to get to with the timing chain cover off, but there's a lot involved just to get that off.


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## 4thGenTinkerer (Nov 1, 2009)

Yeah, oil pan, main crank pully, ac compressor, engine @TDC, exaust, crossmember, ect.etc. Ok well i will get the tapping/rattling on tape and go from there.


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## stillentuned96maxima (Feb 17, 2010)

Since im new to this site, how do you post your own thread for questions you have. because i think im blind. haha


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## joe_yoh (Feb 9, 2010)

whoa, same issue as my cousins', man it became worse as time goes by.


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## 4thGenTinkerer (Nov 1, 2009)

4thGenTinkerer said:


> Yeah, oil pan, main crank pully, ac compressor, engine @TDC, exaust, crossmember, ect.etc. Ok well i will get the tapping/rattling on tape and go from there.


So i managed to get a few minutes of footage and fair audio of the tapping. 




also have part two during which it becomes a little more pronounced.


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## 4thGenTinkerer (Nov 1, 2009)

And for your vieing pleasure, part two. 



Sounds like Sh*t


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## JNCoRacer (Apr 18, 2003)

OK, its a bit hard to tell without actually being there, where the sound is exactly coming from. It sounds like timing chain slap, but then at times it sounds like something internal to the motor is making contact with something else. 
What's your oil and coolant look like? And I meant to ask earlier if you had a check engine light on. 
One more thing you could check is to make sure your power steering pump, alternator, and AC compressor are mounted tightly to the motor. I worked on a couple of them where the owners didnt tighten them down and they were rattling on their mounts.


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## 4thGenTinkerer (Nov 1, 2009)

Yes, check engine light. P1445 = evap canister purge volume control valve or circuit fault. I knew about that one. New one is P0400= EGR insufficient or excessive flow detected. I probably was in too much of a hurry the last time i removed the intake mani. and screwed up the EGR guide tube gasket. 
Oil is new, castrol gtx 5w 30 clean. New Fram Xtraguard. Coolant is prestone(i think) 50-50 mix. Seems clean, no oil in the radiator or tank. 
I will check out the Alt., powersteering pump, and ac compressor to see if they may be loose in any sense.


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## JNCoRacer (Apr 18, 2003)

OK, you can use a auto stethescope or even a piece of tubing and listen around and see if you can pin point a location of the noise. I cant picture the EGR (even if its totally clogged) causing a noise like that.


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## 4thGenTinkerer (Nov 1, 2009)

Well the AC, alt, and the power steering pump are well torqued. I am gonna call it a day and get an automotive stethescope tomorrow. I keep thinking about just yanking this POS outta my car and spend the $ on a good motor. Wonder what a good 3.0VQDE-K would cost me. Maybe do a 5 speed swap as well.
Either way thanks for your input. I'll keep you updated as to what i decide to do.


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## 4thGenTinkerer (Nov 1, 2009)

The verdict is in. I have determined that this noise is one of three things. 
1. Stickey Lifter. Slow to lubriate- dirty/clogged oil journal 
2. Tappet noise. (shim(s) gaulded or worn)
3. Valve guide(s) and/or clearence.
The source of the tapping seems to originate from the exaust cam side of the head closest to the firewall. I have used my homemade stethescope/piece of tubing to pinpoint this noise. I have ruled out the lower end because it sounds like a sewing machine in the cylinders and the rod bearings I personally installed. (with my bro assisting) I am confidant that the cylinders have compression well within the acceptable range. Also eliminated any possability of timing chain slap or chain fatigue in any sense. All tensioners and guides are within specs. 
To find and determine the final cause of this tapping sound will require tools and time I dont have at this point. So my temporary solution is as follows.
1. Buy higher viscosity oil and slick 50 or equivilent, more viscosity. Swap Bi monthly
2. Drive mellow. Like gramma.
3. Swap Head with spare from old engine at a later date.
I have another complete engine 191K good top end.
The tapping does fade after about 10-12 minutes after a cold start and does not tap after a susequent start a short time later. Those cold starts sound pretty rough though.
Fixed EGR guide tube gasket leak. Cleared codes. P0400 squared away. EGR all better.

What do you guys think? 

Fair assesment? OR Tomfoolery? 

Also was cruzing craigslist, found a 96GLE 5 speed 224,xxx miles $2600. Should I put myself through this?


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