Shatty

While I was having new tires put on my '02 Camaro SS today at the local Goodyear shop, I had them do an oil change (since it was time).

When I went to get the car and started it up, it seemed fine until I revved the engine lightly a few times. When I did so, I heard a fairly loud chattering noise that seemed to be coming from the passenger side cylinder head. The mechanics agreed with me that it sounded like valvetrain chatter/clatter/ticking.

When we checked the oil level, it looked to be a bit higher than the "operating range" on the dipstick (only by a quarter inch or so), so we thought perhaps the chattering sound was being caused by overfilling. So the shop drained the oil again and then refilled it while I watched. However, when I started the car, the valve chatter noise could still be heard when I revved the motor slightly (as I let off the gas). One of the mechanics thought it would go away after the motor warmed up, so I drove the car around a bit, and he was right -- the chattering sound disappeared.

However, every time I start the car, I now have the same chattering sound. It starts after about 30 seconds and lasts for the first 10 to 15 minutes of driving. It seems to go away once the engine warms up. I think I always had a little bit of valve chatter upon startup, but nothing like this. Anyone know what is going on???

Thanks in advance for any help,
Paul

P.S. - My LS1 is stock, has 40,000 miles on it, and I replaced the spark plugs/wires about 6 months ago. Since then, the motor has been running stronger than ever and it still is, but this noise is driving me nuts!

vettenuts

iTrader: (4)

What weight oil was removed and what weight went in?

Shatty

I always use 5W30 (non-synthetic). I am not 100% certain that the shop used the right oil the first time (although they claimed they did), but I checked it the second time, and it was definitely 5W30.

By the way, it is a beautiful 70 degree day here in DC, so the engine shouldn't be all that cold.

Shatty

After doing a thorough search, it seems that this kind of thing would make more sense if I had changed oil weights or something. As I said above, I haven't, but...

The brand of oil that they use at this shop was not the same as I usually use (even though it was still 5W30). This brand seems to be alot more clear colored than the oil I usually use (although I am sure it is not synthetic). I can't remember the name of the brand, but it definitely was different.

Would using a different brand of oil be enough of a difference to cause this problem? The fact that the noise goes away after the engine gets fully warmed-up makes me think that this might be the case. I think I may switch back to my normal brand of oil and see what happens. Thoughts?

vettenuts

iTrader: (4)

Yes, if you knew the two brands you could look up the viscosity at 40 degrees C, which is a little more than your outside temps but it would provide an indication. My Morel lifters were noisy at startup with German Castrol 0W-30, but not with Amsoil 5W-30. However, the Amsoil had lower viscosity at 40 degrees C than the Castrol so it made sense. In the fall when the temps dropped a lot, the noise came back even with Amsoil.

Shatty

OK, I changed back to my usual brand of oil and my usual AC Delco oil filter... same deal. I am still hearing the chatter/clattter/ticking sound.

On cold start, the noise begins after about 30 seconds and goes away after 10 to 15 minutes of driving. If I then stop and let the car sit for 5 minutes, the noise comes back immediately upon start-up, but goes away after about 5 minutes of driving.

I took the car to a mechanic that I trust, and he thinks that there may be a partial blockage that is preventing oil from getting to the top of the engine as quickly as it should. He suggested that I do an engine flush to see if that clears it out.

What do you guys think? And if I should do a flush, what it the best product/method to use? Is there anything else I should try first?

Shatty

Anybody?

SOMbitch

iTrader: (8)

Search "piston slap" or "cold start knock".

Shatty

I have done so, and I agree that it could actually be piston slap/cold start knock instead of valve chatter, but can that begin randomly after an oil change like this?

I ask because most of the threads that I read on piston slap seem to suggest that it is something that is usually present from the beginning.

Shatty

I am thinking of adding a half-can of Sea Foam to this fresh oil and then changing it again after 100 miles or so. Perhaps that will clear up the noise... what do you guys think?

Shatty

Well, I went ahead and did it, but the Sea Foam didn't help either.

DaddySS

Well hopefully lesson learned not to have a shop like that change your oil. From their comments they are certainly not mechanics.

What kind of filter did they originally put on there?

SOMbitch

iTrader: (8)

Seafoam works much better going through the pvc or brake booster lines.

TopFlite

Carbon build up is not causing your valvetrain noise and therefore seafoam will not fix this problem. I suggest you drain whatever oil the Goodyear shop put in and replace it with 5w-30, 5w-40, 10w-30, or 10w-40 mineral or synthetic oil, your choice.

SOMbitch

iTrader: (8)

He already did with no results. You are right it prolly is not valvetrain noise.

I am not saying seafoam will fix his noise but even GM acknowledges that these engines can have piston slap due to excess piston to bore tolerances. The very short piston skirt(to save weight) amplifies the problem.They have several TSB's out about it. They even started coating OEM pistons in 03 to help.

When carbon builds up on the piston skirt it can cause contact with the cylinder wall resulting in the tick. In these cases seafoam can SOMETIMES help. I have 99 Z-71 that has had this issue for the 110K i have put on her (177k total). It causes no ill effects despite what this website says. www.pistonslap.com There would have been a class action lawsuit and/or recall if it actually did any damage. Tons of threads on this in the 99 up truck section of www.Chevytalk.com I suggest you search there and it is often refered to as CSK or cold start knock because on most engines it goes away after a minute or so. FWIW my truck occasionally ticks when warm too. don't worry about it Even search piston slap on here.