2009 aveo rattle noise on cold startup

[jzore]

my 09 aveo rattles for a few seconds after sitting overnight. If I start it after about 5 hours max, its quiet. Florida weather, so I think its time sitting rather then temp. Its sounds to me like the oil pump is loosing its prime? My info.. I'm a mechanic for 42 years and just about to retire. But I'm hoping some gurus out there can give me their input. Here is the car history, bought this from A customer due to timing belt gone and valve going through the piston. UGH. so 4 new auto7 pistons,rings, reman head from Texas, timing kit,head bolts,seals,gaskets,etc. car runs great, but I'm concerned about the noise. swung back the a/c compressor and checked the oil check valve. checked ok. Scan data,running shows int and exh phasers in spec. So, to wrap a long post, anybody out there have suggestions? (other than if you've been in the field for that long and can't figure it out,yer in the wrong business LOL) thanks

[Deano]

my 09 aveo rattles for a few seconds after sitting overnight. If I start it after about 5 hours max, its quiet. Florida weather, so I think its time sitting rather then temp. Its sounds to me like the oil pump is loosing its prime? My info.. I'm a mechanic for 42 years and just about to retire. But I'm hoping some gurus out there can give me their input. Here is the car history, bought this from A customer due to timing belt gone and valve going through the piston. UGH. so 4 new auto7 pistons,rings, reman head from Texas, timing kit,head bolts,seals,gaskets,etc. car runs great, but I'm concerned about the noise. swung back the a/c compressor and checked the oil check valve. checked ok. Scan data,running shows int and exh phasers in spec. So, to wrap a long post, anybody out there have suggestions? (other than if you've been in the field for that long and can't figure it out,yer in the wrong business LOL) thanks

I had the same problem on my 2009. Noise on cold start-up for several seconds. In real cold temps, the noise was real loud and alarming. After weeks of googling, I figured my best bet was to replace the 2 Variable Valve Timing Solenoids/Actuators with new ones. Relatively easy to replace. AC Delco #55567050. Since I replaced them, the noise is gone. You are partially right, when the VVT solenoid/actuators fail, the oil drains out of the camshaft sprockets. Then when you start it cold, there is no oil in them, and they make quite a racket till they refill with oil. At least, that was my problem. Deano

[jzore]

thanks deano

[Thymeclock]

I had the same problem on my 2009. Noise on cold start-up for several seconds. In real cold temps, the noise was real loud and alarming. After weeks of googling, I figured my best bet was to replace the 2 Variable Valve Timing Solenoids/Actuators with new ones. Relatively easy to replace. AC Delco #55567050. Since I replaced them, the noise is gone. You are partially right, when the VVT solenoid/actuators fail, the oil drains out of the camshaft sprockets. Then when you start it cold, there is no oil in them, and they make quite a racket till they refill with oil. At least, that was my problem. Deano

I had the same problem on my 2009. There are other threads about these solenoids here. But beware - I could not remove them from the block despite using lots of persuasion. I took the car to my mechanic to replace them and he too had difficulty removing them. So realize that they may not come out easily, and be prepared.