Stumped by cold start clatter, not slap or valves

[vertrkr]

I have an '05 Honda Ody with classic piston slap clatter sound but it's not slap or the valves and I'm going nuts to figure it out. I've checked the valve clearance and they are good, changed the plugs, checked every hose connection and so forth.

Here's the kicker, on exactly two different occacsions I've started it cold and it purred like a kitten with no clatter at all. The first is when I checked the valves, didn't make any adjustments, put it all back together and then it started with no clatter, next start later in the day clatter was back. About a month later I decided to pull the PCV & EGR valves, both looked good, put them back in and again it started with no clatter only to return again next start. I can't imagine even if the PCV or EGR was bad it would cause such a noise as this thing really bangs loud like an old desiel.

Recently it's also developed a new noise that sounds like one of the pulley bearings might be going bad but it doesn't always happen and isn't that loud. It has a timing belt and from what I understand only a timing chain with a bad tension pulley might make this clatter. I've tried to isolate the noise with a stethoscope but the clatter is so bad it hammers my ear no matter where I check. I did take it to the dealer but of course they said it's normal, I just threw up my arms in disgust and left.

For the life of me I can't figure why it started up fine 2 times, I stay awake at night thinking about it all the time, wish I was smarter but I'm not giving up until I fix it.

 

[ThirdeYe]

I had the same issue with my car and they also said it was "nothing excessive" and just said my valves were noisy -shrugs- Perhaps it has to do with your exhaust since it's cold, before it expands?

 

[obbop]

Timing chain or belt?

If a chain, could that be a source?

Water pump?

Alternator bearing?

Engine noises are goofy things. Seems to Coot that engine noise can travel, following a conduit of metallic components and emerging into the air from a location other than the original noise source.

Try the old wooden stick trick?

Alternator bearing?

A component that could have variable "slop" in the bearing? Where, depending upon where the bearing is "sitting" against its load-bearing surface, the noise may be transient.

Grab a female passer-by. After she ceases screeching have her use her ears. Males tend to be exposed to more noise and have various levels of hearing loss. Use the female to track down the noise. Make sure you release her when finished, unless she takes a liking to you and wants to make you lunch, do your laundry, replenish the stock of mini-humans.

Good luck!!!

 

[Pablo]

What kind of oil filter are you using?

And you are 100% sure it's not the PS pump?

 

[Papa Bear]

Is it not under warranty ??

 

[Papa Bear]

Sorry, saw where you took it to the dealer.
Maybe it IS normal.

 

[vertrkr]

Thanks for the posts. I'm currently using Pennzoil Platinum 5W-20 & EaO filter although I've tried about 4 different brands of each with no luck. Could be the PS pump but that sound goes away once warm along with the clatter. I'm going to replace the pcv & egr and see what happens.

 

[mechtech2]

Can you take off the drive belt and start it up a few times for a short while? This would eliminate accessories as the culprit.
How about noisy fuel injectors - they can be quite loud. When cold, they can make a lot of noise.
Timing chain/tensioner are also suspects.

 

[vertrkr]

Took off the drive belt and still have the squeak and engine clatter when cold. I'm now thinking I can hear it more from the front bank than the rear. Maybe my cam bearings are going and messing up the valve clearance? I know it's getting bad now as my wife, who's oblivious to such things, finally said he car sounds funny. I've done all I'm capable of so I guess I'll let it get a little bit worse and take it back to the dealer. Want to make sure it's nice and noisy so they can't tell me it's normal again.

 

[mechtech2]

Maybe an oil filter with drainback valve anomalies.
Maybe you have a variable valve system that the oil drains out of, only sometimes?

 

[vertrkr]

Finally took it in and they said the timing belt tensioner was bad and the belt had some irregularties. Not sure if they meant the tension pully bearings or the tension arm was bad. I asked if this would fix the clatter sound but of course the service advisor wouldn't know and said we'll see after it's all replaced.

I wonder if incorrect tension on the timing belt could effect the valve timing and cause clatter. I know if it slipped a cog bad things happen but wonder if the teeth could ride up on the cog a little bit and throw things off.

 

[oilyriser]

loose belt slapping against cover?

 

[Quest]

define "clatter"....

If you may, try taking a capture of that "clatter" sound and then post it on Youtube to share, that way, we can tell what you mean precisely by "clatter"....

Otherwise, it's just wild turkey guessing game...

Q.

 

[ThirdeYe]

Quote:

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Took off the drive belt and still have the squeak and engine clatter when cold. I'm now thinking I can hear it more from the front bank than the rear. Maybe my cam bearings are going and messing up the valve clearance? I know it's getting bad now as my wife, who's oblivious to such things, finally said he car sounds funny. I've done all I'm capable of so I guess I'll let it get a little bit worse and take it back to the dealer. Want to make sure it's nice and noisy so they can't tell me it's normal again.

---

Good luck on that. Every time i've brought my car in to Acura about my clatter noise, they just tell me "It's difficult to hear what you hear." I don't think it's the timing belt because it's brand new, and they also replaced the tensioner & water pump. Hopefully you can figure out your issues, i've given up on mine. I had my oil analyzed making sure whatever this noise was, wasn't ruining my engine and it came out fine. I'm thinking it might be the fuel injectors, as Integras have notoriously loud and clicky injectors.

 

[charbaby]

vertrkr,
My 04 Altima clatters like that. Doesn't matter what oil filter I use(Nissan, PureOne or anything with a silicone DBV). It all depends on the angle in which I park the car. What I mean is: My Nissan's oil filter is on the passenger side of the car. So, if I park the car on a slight angle leaning towards the passenger side of the car(passenger side is a little lower than the drivers side). The oil filter stays more full over the long/longer shut downs. I've had other vehicles that did this also, so I would try to park accordingly if at all possible. Otherwise I try not to worry about it.

 

[vertrkr]

I got it back today all fixed up, no more clatter or squeals. It was the timing belt tensioner and they said it would sieze up and did terminal damage to the belt. They replaced the timing belt, auto tensioner, tensioner pully and idle pully.

Wish I could have talked with the mechanic. I know the squeal sound is just the pully bearings going out but the clatter I don't understand. I mean the clatter was really loud like what an old desiel engine or bad piston slap sounds like. I guess the damaged belt was messing up the valve timing causing a whole bunch of valve train clatter. Hope it didn't cause any wear on the valves. I still got good mpg during this time and uses not a drop of oil so I guess all is well.

 

[DC84]

This has been a common thing in the newer V6's Ive seen Pilots and Ridgelines with the same concern as well as a few Accords. You should have convinced them to install a new timing belt as well. Your vehicle is prone to power steeing pump noises from a leaking power rack or a faulty pump as well if the noises reoccur you may want to look into this. Most likely you were hearing the belt smacking the cover on startup.