Is It A Lifter..............or NOT
 

Last April I bought my '96 SS Camaro, auto, mint, with 90k miles. Car has performed perfectly up until a few weeks ago. Pulled up to an ATM and when the window came down I heard a clicking sound from the engine which I hadn't heard before. Went home, put the car in the garage, left it running, popped the hood and, is was definitely a loud clicking noise coming from the passenger side of the engine. If it was 50 years ago, and I was in my buddies '65 327/300 Chevelle SS, I'd swear it was a sticky lifter. Anyway, the next morning, I started the car in the garage and didn't hear the noise, so I just let it sit there and idle and after 19 minutes I started hearing the noise. Did this several other mornings and always no noise for at least 12 minutes.

I've taken the car to a couple of local reputable shops and both think its PROBABLY a lifter, as these cars were known to have lifter pump-up issues. But, they, and I can't figure out why the clicking noise isn't heard from the moment I start it. It only starts clicking after heat builds in the engine.

I've contacted the previous owner, who was a long-time GM mechanic and he also heard the noise occasionally and scoped the engine and told me it wasn't an internal engine problem, but he too didn't know what it was. He's kinda old-school like me, if it aint broke, don't fix it !!

And, the car runs fine !!! I don't hammer it. It's a cruiser.

Anyone have any ideas !?

whats your oil pressure? when oil heats up it does get thinner and pressure will drop just a bit after heating up.

20+ when idling, 40-60 cruising at 60 mph.

i would suspect a weak lifter, rocker or cam could unhappy but i doubt it.

Ditto,LT1s are notorious for lifter noise. My '93Z always made some lifter ticking but never enough to worry over and it ran like a scalded dog except for when the Opti failed twice.

Maybe try a bit heavier oil and see if it doesn't quiet down a bit.

I'm running Mobil 1 10w40 high mileage synthetic. 2k miles since oil change.

Maybe try some 20/50 next time.

What filter are you running? Carbon getting stuck in the lift is the biggest cause. I like to run between 10-20 micro filters. Mobil one, Royal purple and I think STP higher end one are rated 20 micro.

I do like how people think its a LT1 issue. Yea its a LT1 issue and a 80's 305 issue and a 80's 350 issue and a LS1 issue, I even have it cold in a 2 gen LH6 5.3 LS motor. Its a chevy V8 issue since the mid 80's. I think when they went to roller Cams something went south but since it only happens well outside of warranty there is no need to fix it.

In the summer its not to bad in my LS1 but boy in the winter, it taps cold and then it does it randomly hot, not a lot just every once in a while hot. I bought the car with 42K 3 years ago and it did it then and I have done Good filter/mobile one every 3k. I still think it carbon since Seafoam in the oil seems to temporarily stop it.

I drove my project 96 3800 100K (150K on the motor) and it never tapped. I current own 4 GM V8's none of them tap all the time but the only one that never taps is my 67.

Just checked. It's an AC Delco, original equipment-type filter. Previous owner changed oil and filter just prior to selling me the car and he liked keeping everything as original as possible. When I change in another 1k miles, will definitely change to a Mobil 1 filter.