Initial engine noise durning startup; 2.2 Ecotech

A 2.2 Ecotech 4 cyl. on a '06 Mailbu with 21k miles, for the first 2 or so seconds there is a louder and noticeable noise untill the oil circulates and pressure builds up. It is hard to describe, but I would say it is between a rattle and chattering type of noise. My first thought was the valves. I described it to my mechanic and he said the main bearing. Unknown when the oil was changed last.
The car ran fine, idles fine, no knock or anything while driving. Just for a brief 2 seconds when it was cold when I heard it. My concern is down the road, after a few thousand miles, when it is out of warrenty and something happens. The car was a NJ rental.

Any ideas?

My '04 Classic (ecotech) has been doing the same thing since I bought it 60,000 miles ago. Overhead cam engines take a little time for the oil to get to and pump up the lifters (pushers?). I have been running Amzoil since I got it at 13,000 miles and it now has almost 74,000 miles and runs like a top.

That sound isn't present on two other 2.2's.

This has been a problem with GMs since the early 90's and probably even before that. When an engine sits for a few hours all the oil in it drains down to the bottom and into the oil pan. When you go to start it again, the oil pump doesnt come on instantly, instead it takes a few seconds to get moving and then a few more to get the oil pressure built up enough to get it into the engine, ESPECIALLY when its cold. I've had a 1990 suburban, a 1995 beretta, a 1998 malibu, and now a 2004 YukonXL, and every one has done it. My dad, who has been a mechanic for over 30 years, says this is completely normal and will not damage your engine as long as it goes away within 8 seconds. Longer than that, you've probably got a more severe problem. But, if it makes you feel better and your car is under warranty, go to the dealership and have them check it just to make sure everything is ok. That is your safest bet. I seriously doubt it is the "main bearing".

When you go to start it again, the oil pump doesnt come on instantly, instead it takes a few seconds to get moving and then a few more to get the oil pressure built up enough to get it into the engine, ESPECIALLY when its cold. I completely understand this.

To describe the 'noise' better, it orginates from the top of the motor, sounds as a cross between tappets and valves 'clicking' very rapidly for around two seconds then fades out and the engine rund fine. Exactly as you described.

My problem with this is it's not on all the cars I have listened to including my Classic. I would understand if all of them did this to varying degrees, but they don't. It seems to be either they do or they don't. There doesn't appear to be any grey area which would tell me something is wrong.

One service department told me it was the timing chain and a tensioner which made sense the way he explained it if it was some other type of noise, but that surely wasn't what I heard.

I'm just worried about this being a 'smoking gun' down the road long after the warrenty runs out. Hope you understand.

Bruce, my brand new 2.2L makes the 2 second clatter on every cold start. I purchased the car with 4mi on it. You hear of many different takes on what the noise is. Piston slap, the hydraulic lash adjusters, timing chain tensioner, etc... It sure does sound oil related, but there is no way to tell. The only odd thing IMO with this design is, when you swap out the drop-in oil filter cartridge, the housing is empty of oil. The whole housing has to fill with oil before you get oil pressure. Startup noise aside, I love my little 2.2L. Very smooth, great power (in a Cobalt), easy maintenance.

Joel

when you swap out the drop-in oil filter cartridge, the housing is empty of oil. The whole housing has to fill with oil before you get oil pressure. Interesting tidbit. At least when you change out the insert, you won't get a waterfall of oil flowing out of the container.
Since you mentioned it, why was it done this way, the cartridge within a can instead of a nornal filter??

Thanks for the reply. The last sentence of my last post was my concern.

IMO it's oil filter related from what I've seen and heard on this engine.

Then why don't all of them do it?
I would understand if all did it to varing degrees, but well over half of the ones I have listened to had NO noise what so ever. :confused:

I've found that not only is it filter related, but oil types as well. It's not as clean cut as many would want.

Since you mentioned it, why was it done this way, the cartridge within a can instead of a nornal filter??




Supposedly, drop in elements are more 'green' with less metals/materials needed. I really like the 'drop-in' design of the ecotec oil filter. I'm one of those nuts that actually cuts open my used oil filters for inspection. No need to do that with the ecotec. As far as the 2sec cold start rattle, I've heard lots of makes/models do this and it never seemed to effect longevity, at least in the rust belt. Everything else breaks on our cars long before the engines wear out.

Joel

Supposedly, drop in elements are more 'green' with less metals/materials needed. Is it a 'cost' issue durning manufacturing??

It's piston noise that gm has tried to repair with ill affect.No different than in the racing days. Drop in a forged slug and it makes noise ( maybe) drop in a cast slug and all is hush ( till a skirt breaks )

"Forged & cast slugs"???

Is it a 'cost' issue durning manufacturing??

That's a possibility. Shipping this type of filter by the truck load to the engine plants probably costs GM less. Less weight, less packaging, can fit more per case, etc..? They are not any cheaper from a consumer standpoint, but maybe by buying bulk, you see a difference.

Joel