Rattle for split second at cold 50 degree and below startup - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

travfreed · 12-08-2019, 01:14 PM

Well, Merry Christmas all. I bought a 2010 RS. Great running car. Last winter (in Cali) I noticed a loud but very short Rattle under the hood during start up. Took it to dealer for warranty work. He said the issue was due to me using oil other than AC Delco DEXOS 2 oil. (I changed the oil with Pennzoil DEXOS2 many times prior to this issue). Dealer said he replaced timing chains, chain giude, and tensioner Gratis. By the time this was complete it started to warm up to summer and I hadn't heard the noise till about a week ago, when the temps dropped and I heard it, faintly again. Anyone have this issue? Could using Pennzoil DEXOS 2 have been the cause?

Thanks all

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pnwdan · 12-08-2019, 01:23 PM

Quote:

Originally Posted by travfreed

Well, Merry Christmas all. I bought a 2010 RS. Great running car. Last winter (in Cali) I noticed a loud but very short Rattle under the hood during start up. Took it to dealer for warranty work. He said the issue was due to me using oil other than AC Delco DEXOS 2 oil. (I changed the oil with Pennzoil DEXOS2 many times prior to this issue). Dealer said he replaced timing chains, chain giude, and tensioner Gratis. By the time this was complete it started to warm up to summer and I hadn't heard the noise till about a week ago, when the temps dropped and I heard it, faintly again. Anyone have this issue? Could using Pennzoil DEXOS 2 have been the cause?

Thanks all

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I dont know if Pennzoil is the issue but everyone I know that has used it in the past few years has had slugging problems. I use Castrol or Mobile in my normal cars. I use Rotella T6 in my Camaro.

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CamaroBarb · 12-08-2019, 06:47 PM

1st of all DO NOT use DEXOS 2 oil! You need DEXOS 1 gen 2 oil! Big BIG difference between the 2 oils! DEXOS 2 is diesel engine oil. DEXOS 1 Gen 2 is gasoline engine oil.

You are experiencing the cam actuators not locking up at rest. When you shut off the engine there is no oil pressure to the cam actuators and a spring load pin jumps out to lock the cam to the actuators. You have 4 cams and 4 actuators. At start up what should happen is the pins lock the cams to the actuators UNTIL there is enough oil pressure to push the pins back into the actuators. For some reason(probably from using the wrong oil) dirt or sludge has built up either in the oil passages or the actuators and the pins are not releasing properly. The quick rattle you hear is the pin jumping in and out of the hole in the cam. I'd try Pennzoil Platinum DEXOS 1 gen 2 5-30 with a AC delco filter and see if it stops the noise. This is common problem with these engines.

There is ABSOLUTELY nothing wrong with Pennzoil oils. Any one who says they sludge up motors is painting a fairy tale!

Greenhornet2 · 12-08-2019, 08:04 PM

GM has a lot of problems with timing chains stretching and cam actuators not locking on v6s. You might be en route to new cam actuators, and solenoid valves.

CamaroBarb · 12-09-2019, 05:58 PM

Good read here with the fix https://www.cadillacforums.com/threa...art-up.825393/ replace the cam phasers

12-08-2019, 01:14 PM	#1
travfreed Drives: 2010 Camaro RS Join Date: Nov 2019 Location: US San Diego Posts: 16	Rattle for split second at cold 50 degree and below startup Well, Merry Christmas all. I bought a 2010 RS. Great running car. Last winter (in Cali) I noticed a loud but very short Rattle under the hood during start up. Took it to dealer for warranty work. He said the issue was due to me using oil other than AC Delco DEXOS 2 oil. (I changed the oil with Pennzoil DEXOS2 many times prior to this issue). Dealer said he replaced timing chains, chain giude, and tensioner Gratis. By the time this was complete it started to warm up to summer and I hadn't heard the noise till about a week ago, when the temps dropped and I heard it, faintly again. Anyone have this issue? Could using Pennzoil DEXOS 2 have been the cause? Thanks all Sent from my SAMSUNG-SM-N920A using Tapatalk

12-08-2019, 08:04 PM	#4
Greenhornet2 Drives: 2011 Camaro 2SS LS3 Whipple Join Date: May 2019 Location: Connecticut Posts: 1,925	GM has a lot of problems with timing chains stretching and cam actuators not locking on v6s. You might be en route to new cam actuators, and solenoid valves. __________________ Whipple 2.9 CAI ID1050x injectors ZL1 Pump JRE FPCM JMS Voltage booster JRE Rough Idle blower cam BTR .660 springs CHE trunnion kit 1 7/8 Speed Engineering Borla Atak JRE scoop 1.5" lowering springs BMR trailing arms and toe links Cradle inserts 704WHP 603WTQ 93 octane

12-08-2019, 06:47 PM	#3
CamaroBarb Banned Drives: cheby Camaro Join Date: Aug 2019 Location: usa Posts: 575	1st of all DO NOT use DEXOS 2 oil! You need DEXOS 1 gen 2 oil! Big BIG difference between the 2 oils! DEXOS 2 is diesel engine oil. DEXOS 1 Gen 2 is gasoline engine oil. You are experiencing the cam actuators not locking up at rest. When you shut off the engine there is no oil pressure to the cam actuators and a spring load pin jumps out to lock the cam to the actuators. You have 4 cams and 4 actuators. At start up what should happen is the pins lock the cams to the actuators UNTIL there is enough oil pressure to push the pins back into the actuators. For some reason(probably from using the wrong oil) dirt or sludge has built up either in the oil passages or the actuators and the pins are not releasing properly. The quick rattle you hear is the pin jumping in and out of the hole in the cam. I'd try Pennzoil Platinum DEXOS 1 gen 2 5-30 with a AC delco filter and see if it stops the noise. This is common problem with these engines. There is ABSOLUTELY nothing wrong with Pennzoil oils. Any one who says they sludge up motors is painting a fairy tale!

12-09-2019, 05:58 PM	#5
CamaroBarb Banned Drives: cheby Camaro Join Date: Aug 2019 Location: usa Posts: 575	Good read here with the fix https://www.cadillacforums.com/threa...art-up.825393/ replace the cam phasers