When I start the car up it'* next to a fence which amplifies sounds. Yesterday next to the fence the motor started to sound like a sewing machine, tick tick tick tick tick tick tick tick tick tick tick tick. The sound is the same idling in neutral as it is rolling at 5mph. If it'* idling in neutral and I rev it the ticking gets faster. Of course as expected ambient traffic/tire/etc noise as I chug along at 35mph mutes the ticking (or my ability to hear it), but it seems to mute even more as the engine warms up a bit over a couple of miles. That could be my marginal hearing or subjective. Today was the same, btw. I just had an oil change 500 miles ago, at 79k. I can't/don't work on motors, so of course if this continues I'll have it checked by a pro. But what diagnosis should I expect to hear, what diagnosis should I be wary of, and what would be the ballpark cost to fix a correct diagnosis?

does the noise eventually go away? what year and engine displacement. I have a 2003 that the around that year they had a trouble with " piston slap) as the piston warms up it expands and the noise goes away. I have the factory service manual for my car and in regard to such engine noise it should not last more that a minute or 2. Does your car require synthetic motor oil ? did you just have your oil changed or the last time was regular oil used. when you first turn the key is there an oil pressure indicator that goes out when you start the car?

I Tried to edit my post, went past the 5 minutes... lol
so is this the 2003 Bonneville in your sig? check your oil , pull the dipstick look for coolant in the oil , mayo looking stuff at the top of the stick, the oil looks like chocolate milk and oil in the coolant overflow tank

Try adding a bottle of this to the oil.
LUBEGARD BIO-TECH Engine Oil Protectant
This sure quietened down my valvetrain in 1 minute flat. I now use one at every oil change , gas mileage went up a bit too.

It'* an 03 Bonnie V6 3.6 non-*'ch. I just took it out for a 3-minute 40mph spin. First, no startup oil pressure light I could notice, so many lights came on, twilight. But I did look around and saw no oil pressure light. Yes, it was ticking again at start and then again at the end back in my driveway up to the fence - still ticking, no change. So "eventually" is broad, maybe it would go away after 10 minutes, or 45, or who knows. As for the oil, it'* only had non-synthetic for the 15k 5 changes I've owned it. This last change was 590 miles ago.

just checked and the oil looks totally normal, very light and clean, and same with the coolant. thanks, tho

Sounds like it could be a collapsed lifter. I don't see where you live anywhere in your information ... are you into cold weather yet? Try using a wooden dowel, the core out of a roll of paper towels or something similar to listen to the engine to see if you can isolate where the ticking is coming from.

Noted, thanks, and available at a couple of locals. The A'zon words say "Eliminates lifter and other objectionable noise on startup, especially in cold weather" - but it'* not very cold, c.50F, and the noise lasts well beyond start, so not too sure.

I live in Mass, around 50F today and yesterday. With this hollow tube listening method, even if I could tell the diff I wouldn't know what to call the area, never mind the part...

p.*. let'* say it'* a "collapsed lifter" as you suggested, would that be expensive to have a pro fix?

OK I just ordered some from A-zon. $7.69 for 11.4oz on Prime 2-day, way better than the NAP price. So I'll try some and see if it helps.