Tapping Noise- not Toyota tick

My Taco has had a tapping noise for quite some time- it sounds like loose pebbles slowly bouncing around in the engine; it is more noticeable when the truck is in gear with the brakes applied and less noticeable after about 1500 rpm. It's more easily heard from within the cabin and almost completely goes away when the engine is at full operating temp. I took it to Toyota service last December when I had 35k miles. The tech diagnosed on his own and advised the tapping was normal.

Today, I took it in again (54k miles), for the tapping noise and the gas pedal recall. the complaint is exactly the same, except the sound is more noticeable. I parked the vehicle at the dealer last night and kept the key so I could meet the tech when the vehicle was first started. The techs both heard the tapping and said the sound wasn't normal. One of the techs (master tech) said it may be coming from the transmission area because it's not noticeable from outside of vehicle. He said he would use a stethascope once he got in a garage bay.

At about 4pm, the service consultant called and said when the tech took it inside, he couldn't duplicate the sound. He said I may have to pick it up before the night was done. He called back at closing time and said that if I could leave it overnight, they would try with a steathascope in the AM. I agreed.

I suspect that they didn't try the stethsacope today and merely stopped diagnsotics after they didn't hear it in the garage, but I can't prove it. I also suspect that they won't be able to find the source tomorrow- but I ramain hopeful. The service consultaant said that if the problem isn't found or is found and it's not a warranteed item, I have to pay $52 diagnostic fee, plus repair price. I already called Toyota Care and opened a case because I reported this issue while the truck was under 36k bumper to bumper and they said it was normal. I don't think I should have to pay at all because I reported the issue while it was under a full warranty and they ignored the problem.

Does my arguement seem reasonable?
Am I sol?
What could the tapping be?

 

Tuesday bump

 

Chris4x4 posted these a while back:

http://www.tacomaworld.com/forum/2nd-gen-tacomas/43632-ticking-engine-one-fix.html
http://www.tacomaworld.com/forum/performance-tuning/8967-engine-ticking-rattling.html

 

I'm familiar with those links and the Toyota tick. Mine is not a "tick," the techs that listened to it with me yesterday confirmed it's not a "normal" sound. The tapping I'm referring to can be heard separate and apart from the tick.

About 15 minutes ago, I received a call from one of the tech's and he advised it may be rattling coming from the wiper assembly transmission mechanism, he said something about the mechanism being defective and a "ball" coming lose? This may explain why the noise is heard inside the cabin. I'm not too optomistic on this being the cause, but hopefully it is. If so, I know I will run into warranty coverage issues. Thoughts?

 

Anyone have a similar situation?

 

BMP

 

The windshield washer mechanism was not it. Dealer now has the cowl apart looking for the problem. The service manager hears the noise too and said the techs ruled out anything engine/transmission related. Truck has been at dealership since Monday...

 

I get this sound occasionally on cold mornings before the truck warms up. Exactly as you described it; only being heard when in gear with the brakes held at idle. The sound is more noticeable in the cab because the first time I heard it, I set the parking brake to hold the truck while in drive (not the greatest idea, but the only option I had) and popped the hood to find I couldn't hear it. It almost sounds like a rod knock, but that would be louder under the hood. Keep me posted with what you find!

To those who are wondering, this is NOT the standard engine tick.

 

Since you reported the sound at 35k I think they should take care of the bill.

 

Service manager said he will try to get it covered. In the meantime, I will probably be given a courtesy loaner since they haven't found the problem. I assume that since they're giving me a loaner, the job will be at no cost- keeping fingers crossed...

 

I'm in a 4Runner now, taco's cowl is in pieces at dealer and they can"t find problem. Now they say it sounds like it's coming from d-side wheel well area, may be fuel line fluttering...

 

Damn Op, that sucks... Hope they find it. I hae no idea what it could be. I'd have to hear it in person, and never noticed anything like this on my truck.

 

I originally described it as a rod knock type sound. Now that I think about it more, it almost sounds like something on the firewall is loose and thumping against the firewall due to the engine shaking at that certain RPM. It's not that annoying to me, really. I could live with it as long as it isn't a rod knock or loose transmission mount or something like that in the driveline.

 

Maticuno, What you are hearing is probably piston slap, search it on Youtube to hear what it sounds like. It typically happens in colder weather.

OP, I would ask them to check all of the idler pulleys with the stethoscope if they haven't already. They tend to make tapping/knocking sounds when they are really worn, im assuming they checked the water pump and other accessories already.

With the 1GRFE so many things can make noise but its designed for longevity, not luxury.

 

They said they put it on a lift and used a stethoscope on all driveline parts, I'm not sure of the components they checked. The last word was that they isolated the issue to the d-side wheel well. I have to wait til Monday to learn if they made progress.

 

Today, the service consultant called and said they can only duplicate the noise for the first few minutes and the short duration does not allow them enough time to find it. As such, they're not working on it any longer and are closing the ticket. This stinks cause it appears I may be stuck with the noise forever. The diagnostic fee is $52, but I think the service manager is going to waive it. Thoughts?

 

I searched you tube for "piston slap" and that's what it sounds like. It may be common, but it certainly isn't "normal." What should I do?

 

Mine will do it for about 5 seconds when its below 0* celsius out. In terms of todays vehicles thats very minor. I know it shouldn't do it at all but I have quite high mileage.

Let the truck wake up a bit before putting it into gear. 45 seconds to 1 min on a cold day, its probably good for the truck anyways, everyone says slapping it into gear and driving is the best way to warm up a vehicle but that seems to apply to fuel economy only. My thought is this might only be a problem with automatic trucks because there's a load on the engine at idle in gear with the brakes applied.

I would imagine synthetic oil would help as it "clings" to the cylinder walls better and wouldn't "wipe away" as easy on a cold start. Only my theory though, I might just try it out.

I wish I just had a nice warm garage to park in.

 

Everything I read about piston slap said that it is not a death sentence. That being said, I will certainly let my truck warm up a little while longer than I used to before putting my foot into it.

 

Ive heard the same thing. The 1GRFE sure is noisy, but.. I've never heard of a major failure yet that wasn't due to neglect. Im quite happy with its build quality, it could just be a bit more refined like Nissan's V6.