cold start valvetrain noise, 10 minutes +?

[k24a4]

I have a 2004 Honda Accord EX, 5-manual, with 78500 miles on it. It is my first Honda, and I live in the Northeast. For the past several years, I would say since around 40,000 miles, when it is 40 degrees or colder, the car makes what I would best describe as a "clacking" noise on cold start-up. But unlike some descriptions I've read of valvetrain noise which go away after 1-3 minutes (valve tappets?), my engine "clacks" away like a mini-diesel for 10-12 minutes in stop and go traffic, which I guess is the time it takes to get to full operating temperature?

The noise is not pronounced at idle but gets louder under load, to the point where it is intrusive.

I'm the original owner. The car had 36 miles on it when I bought it. The factory fill was changed at 4000 miles, with 5000 mile oci's to follow with Kendall GT1 until ~45,000 miles when I started to do my own oil changes with pp and a pureone filter. From what I can see under the oil cap the valvetrain is pristine. My gas mileage has always fallen within the 26-34 mpg estimate.

From doing research on Honda sites I've heard everything from, "this is normal for Honda engines" to "piston slap" to "get a valve adjustment". Any thoughts?

I plan to do my first oil analysis in the Spring when I have 6000-7000 miles on the oil (pp).

 

[flatlandtacoma]

Time for a valve lash adjustment.

or you could just blame the oil, find one that muffles the noise, and pronounce it "better"

 

[k24a4]

I should add that it is the I-4 with a timing chain.

 

[Kuato]

I'd wonder what grade of oil you're using, and what's recommended.

 

[Bill in Utah]

Originally Posted By: fredjacksonsan
I'd wonder what grade of oil you're using, and what's recommended.


Sig line has;
'04 Accord 5-manual 74800 mi pp 5w-20 pureone

and 5w-20 is what is recommended in that engine.

To the OP. Sounds like piston slap to me. Its annoying but may engines from all makes have this "issue" and seem to run forever. Loud but run...

Bill

 

[JOD]

I'd adjust the valves. I just did them on a friend's CRV, which sounded like a marching band, '03 with 60K miles on it, same engine.

The car sounds kinda like a sewing machine by design, but if it's getting louder under acceleration, my bet is that the intake valves are out of adjustment.

 

[addyguy]

It's not the valves, it's piston slap. Very little cures that.

Nothing to worry about.

 

[k24a4]

thanks so far for the replies and, yes, 5w-20 for all the oci's as per Honda's recommendation.

I would add also that once the car has fully warmed there is no more clatter and the engine does, indeed, hum along like a sewing machine. Love the k24 and 5-manual combo; we need a "save the manual" campaign in the US.

I don't drive like a madman, either, for what it's worth. Easy does it until the noise goes away and not much harder after that.

It is interesting to note that the miata makes no such noise and has more miles on it; although it is stored in the Winter it does get "colder" starts in the Spring and Fall.

thanks again for the input.

 

[modularv8]

Originally Posted By: k24a4
I should add that it is the I-4 with a timing chain.


Glad you mentioned the timing chain. I have seen several Honda and other engines make the noise you are describing. Does it get louder the colder it is outside? It is possible you have a stuck hydraulic timing chain tensioner. When it is cold outside, the engine block/head will contract enough to allow slack in the timing chain. The "clacking" sound then gradually goes away as the engine warms up (thermo expansion) because now the chain is tensioned. The ratchet/hyraulic tensioner in these engines are designed to compensate for these thermo changes in order to provide the proper timing chain tension. Without this mechanism, it is possible to over-tension the chain when the engine is at operating temperature (expands the chain). A stuck tensioner when it is cold (~40F) will cause the chain to slap the guides a little making a "clacking" sound which is more pronounced under load. Sometimes just a little varnish in the cylinder bore of the tensioner can cause this to happen.

 

[Quest]

first and foremost: adjust all the valves first.

Q.

 

[demarpaint]

4 cyl Honda, I'd adjust the valves, it might help, it certainly won't hurt. If it is piston slap you'll have to live with it, or try and muffle it, that's if it really bothers you.

 

[A_Harman]

At 78500 miles, it couldn't hurt to adjust the valves. But since you say the engine makes a "clacking" noise, that would point to piston slap. My Camaro has made that noise since day one, and still runs good at 150,000 miles. On my car, I find that if I rev it up to ~2000 rpm while still cold, the clacking goes away, then if I let it drop back to idle, the clack comes back. Once the engine gets up to operating temperature, it's silent.

As a diagnostic exercise, you could start the engine up on a cold morning and listen carefully at different points around the engine. If it's piston slap, you would be able to hear it equally all along the engine. If it's the timing chain, the noise would be localized at the front of the engine.

 

[mikiee]

Would trying a different oil filter, help? Maybe go back to a genuine Honda filter. On a related note: What exactly is piston slap? What's going on in the engine?

 

[Mau]

My dad's 96 Accord with F22B2 also does the same. Sounds like a diesel but once warmed up its smooth.

I'm trying a run of MMO in it currently to see if it will cure it but in my research this is normal for the F22. I guess its normal for the K24 as well.

 

[ARCOgraphite]

Possibly another victim of inadequate oil and E10 fuels. If an engine is this noisy full warm, and fuel mileage has dropped 15% and excess fuel is shown in a proper UOA - I would declare it 'toast'. Mine is heading down the drain this winter - Im trying to run "normal" (cat saving/engine eating) oils but it aint working. Back to the Olympic SH/SJ "HDEO" 5w-30 synthetic with zinc/phos to the limit! Its amazing what 1600ppm zinc can do.

 

[ARCOgraphite]

Also check (with stethoscope) at fuel injectors - they may have succumbed to the lousy E10 we get up here in the northeast.

 

[A_Harman]

Originally Posted By: mikiee
On a related note: What exactly is piston slap? What's going on in the engine?


Piston slap is a result of the piston traveling back and forth across the cylinder due to connecting rod thrust. When the engine is cold, the pistons have more clearance to travel through, and build up enough velocity to make noise when they contact the cylinder wall. Because pistons are aluminum, and most engines have iron cylinders, additional cold clearance is built into the engines so that the proper clearance is achieved when running at operating temperature. This is why piston slap goes away when the engine gets warm; the bore clearance decreases.

 

[KrisZ]

Could piston slap last that long?
From the description it may very well be piston slap, but I would not rule out timing chain tensioner.

 

[SteveSRT8]

It is extremely unlikely for piston slap to last that long.

Typical aluminum piston warms in literally seconds.

 

[meep]

I've had 2 cars with piston slap. 97 subaru had since nearly new, and warmed up in 1-2 minutes into silence.

bought a 4.0L jeep late in its life, it was there all the time.... thicker oil softened the sounds some.