Starting many winters ago (mainly since I've deleted the mechanical fan), I've noticed a clacking noise in my 93 Caprice's engine (TBI 350), upon cold start in cold weather. It wasn't very apparent at idle, but while accelerating, it was very noticable (my dad, who usually has trouble hearing things like this, mentioned the noise, and this was a couple years ago, just to show how long it's been going on). This noise would go away after a few minutes and wasn't even present unless temps were cold (like below 45°F). Oil pressure was always good (50-55psi on cold start). The engine has been Seafoamed, used mostly M1 10W-30 and recently I completed a full ARX treatment. It's got 211k now.
Recently, I decided, along with my girlfriend's dad, that the noise was probably coming from a wrist pin and there was really nothing to be concerned about. Oil pressure is fine, which is why I don't think it's a pressure lubed clearance issue. So I've been living with the coarse sounds/clacking (seemed worse under light load).
At about 209k miles, when I finished my 2nd ARX rinse, I switched from the rinse oil, GTX 5W-30, to GC 0W-30. I noticed no change in anything. Mileage, noises and power seemed the same.
Fast forward to this week, 211,xxx or so. A couple mornings ago, I start my engine to go to work. It was cold. As I pulled out of my apartment complex, and began to accelerate, I happened to notice that the engine noise had almost completely gone away. Engine noise mostly consisted of the baritone note of my Dynomax dual exhaust. Thinking it was a fluke, or that I was going mental, I didn't think much of it, until I left work and noted the same lack of engine racket. Next morning was the same deal, and same with this morning. There is still some engine noise, but I think that's loose timing chain noise (I hope timing chains can make noise without rubbing on the timing cover...).
I haven't checked the oil this week, but I think it'll be somewhere around halfway up the crosshatch on the dipstick.
I'm not sure whether to be worried or happy! Is the GC doing something in mid-OCI? Did the ARX rinse continue with GC and fix something? I should note that for the entire duration of the ARX treatment (both cleans and both rinses), the noise was always present in the exact same volume. It was NOT improving as the treatment went on. Rather, it seems to have completely disappeared from one day to the next.
Certainly, I'll continue to listen to the engine, as I am curious if it will stay quiet. That would be an amazing achievement, considering all I've done for/to this engine.
I have 2 quarts of GC left and I was thinking about using at least one quart to top off the oil when it needs it (still consumes after the ARX treatment) and continue a somewhat-extended OCI.
Stay tuned, I guess! If the noise comes back, well, then I guess it was a fluke. But if it doesn't ...
Recently, I decided, along with my girlfriend's dad, that the noise was probably coming from a wrist pin and there was really nothing to be concerned about. Oil pressure is fine, which is why I don't think it's a pressure lubed clearance issue. So I've been living with the coarse sounds/clacking (seemed worse under light load).
At about 209k miles, when I finished my 2nd ARX rinse, I switched from the rinse oil, GTX 5W-30, to GC 0W-30. I noticed no change in anything. Mileage, noises and power seemed the same.
Fast forward to this week, 211,xxx or so. A couple mornings ago, I start my engine to go to work. It was cold. As I pulled out of my apartment complex, and began to accelerate, I happened to notice that the engine noise had almost completely gone away. Engine noise mostly consisted of the baritone note of my Dynomax dual exhaust. Thinking it was a fluke, or that I was going mental, I didn't think much of it, until I left work and noted the same lack of engine racket. Next morning was the same deal, and same with this morning. There is still some engine noise, but I think that's loose timing chain noise (I hope timing chains can make noise without rubbing on the timing cover...).
I haven't checked the oil this week, but I think it'll be somewhere around halfway up the crosshatch on the dipstick.
I'm not sure whether to be worried or happy! Is the GC doing something in mid-OCI? Did the ARX rinse continue with GC and fix something? I should note that for the entire duration of the ARX treatment (both cleans and both rinses), the noise was always present in the exact same volume. It was NOT improving as the treatment went on. Rather, it seems to have completely disappeared from one day to the next.
Certainly, I'll continue to listen to the engine, as I am curious if it will stay quiet. That would be an amazing achievement, considering all I've done for/to this engine.
I have 2 quarts of GC left and I was thinking about using at least one quart to top off the oil when it needs it (still consumes after the ARX treatment) and continue a somewhat-extended OCI.
Stay tuned, I guess! If the noise comes back, well, then I guess it was a fluke. But if it doesn't ...
