2RZ tick/slapping sound at idle and warm

1999 2RZ Auto 136.5k miles.

Only had this car for a couple of days so here is what I've noticed so far. Doesn't happen when cold (probably because cold engine running higher RPM and is louder which hides the noise?). Only when the engine is warmed up and sat for say 10-20min. Say park somewhere and start it up in a bit and leave it in idle.

My research so far shows to look for the following

- Check the valve clearance
- Check the exhaust manifold for the common crack

Before I do these checks, thought I check with others on opinions of what it might be. Here is an image of the engine temp + tach and the youtube video of the engine sound.



http://youtu.be/Y-hPHQlbErc

 

sounds like the valves to me or a timing belt slapping if even possible. it almost sounds like the old quad i had, except it was the cam chain that was making that sound since it was loose and slapping the head

 

I agree with Austin. The valve train area is your most likely culprit. Good thing is, you can run that engine with the valve cover removed (at idle) to trace the fault a little closer. Look at the tops of the valve tappet shims for damage or movement.

 

Wow, thats pretty nice. So I assume I have to remove the air intake piping, coils, various connectors, valve cover, and then rehook up the connectors + air intake to run the engine with the valve cover off for better observation? I'm assuming there will be minimum oil splattering around at idle with the valve covers off?

 

sounds weird to me. Hard to tell from the video. I suggest taking it to someone with experience. Engine sounds are something that you can only really learn from experience. Doesn't quite sound like the typical rod knock or lifter tick to me.

 

sounds exactly like my yfz 450 when its running those all do that, the valves make a ton of noise with the 5 valves. thats the only reason i can almost 100% say its something to do with the valves

 

I had a similiar noise in my 94 nissan hardbody.. does it get louder when you rev up? If so, it may be time for a new timing chain - (thats what happened with mine). The chain may have become loose/stretched and is now slapping against the guide.

 

You are correct, you can remove those needed to access the valve cover, then reinstall only the parts needed (plug wires and air inlet due to MAF sensor) Then you can see if it would be possible to narrow down the noise. Either way, if you are not tech savvy enough to replace a timing chain or valve train repairs, you should just take it to a quality shop and have it inspected and diagnosed there.

 

tapping sound disappears when revved up even slightly.

BamaToy1997, thanks for the clarification. Thought I double check before doing it. I've maintained my own 2001 Volvos for the last 10 years and have done the PCV (PITA on those cars, have to remove the intake minifold), steering rack, struts, tie rods, throttle body and a whole bunch of electronic diagnostics with the factory computer tool... Checking the exhaust manifold + valve adjustment seems very doable on this truck and in my skill range. As you pointed out, knowledge and experience is everything so wanted to double check the knowledgeable folks here before proceeding

By the way, this tapping sound seems very temperature and RPM specific. It is most pronounced after the car is warmed up but sat for say 20min or so. I can hear the tap tap sound inside the cabin. But not when the truck is fully warmed up and shut off followed by a start up (can hear the tapping maybe briefly but goes away). I also hear some loose vibrating metal like a heat shield so I'll definitely take a look at the exhaust side first.

 

Here is a follow up

Valve clearance is good.

Exhaust Spec (.010 - .014)
Exthaust (front) .011 .011 .012 .012 .012 .012 .012 .012
Intake Spec ( .006 - .010)
Intake (front) .007 .008 .008 .008 .008 .008 .008 .007

No exhaust manifold crack

Have some common heat shield crack. Removed heat shield and engine still make same noise.

Don't know how to check the timing chain but the chain and the guides felt pretty sturdy. Here are some pics





My search on the web came across others with this noise on the 2rz engines. Most said the the cause is wrisp pin. But it seems this noise does no harm to the engine. Got plenty of power (for 2rz anyways) Doesn't burn oil etc...

Pulled the spark plug wires one by one and started the engine. The tapping sound disappeared with #1 cylinder wires out. The engine ran somewhat unbalanced with some of the wires out but #1 cylinder wire definitely eliminated the tapping sound. So whatever I've got seems to be in cylinder #1. I think this test + valve clearance check pretty much eliminates the valves.

The sound is very low RPM dependent. I reason that cold start will keep the idle at 1K RPM or higher so this is the reason the tapping sound only appears when warm.

UPDATE 9/24/2012

Took it to an experience Japanese auto mechanic (#1 rated in Seattle) and he said he has heard this noise on 2RZs before. The sound is from the bottom end (not the head). Isn't the crank bearings. He thinks it is either the wrist pin or thrust washer on the crankshaft. He said it isn't a problem and the truck run well for many miles to come. This matches what I've read online on this sound.

 

sounds about right. My ticking is not as pronounced as yours but it is there.

 

What's that little lever and hook doohickey in the second pic? Is that the hydraulic tensioner, and that hook and pin keep the component compressed until installation? At which time you release the pin and the unit applies the tension?

 

Mine is making the same noise, thought it was a vavle but now Im leaning more toward the infamous lifter tick.

The noise started after I did a cleanup with seafoam. Even thought it was an injector.

Any info on this would greatly be appreciated.

 

Engine type would be helpful.

Mine wasn't on the top end, mechanic agreed it was on the middle/bottom of the block.

You can disconnect spark plug one by one and see if that changes the sound.

 

Sorry about that, I have a 2000 1/2 2.4 stepside bed extracab.