Oil (regarding 98 MC)

I'm due to change the oil in the 98 Monte Carlo this weekend, so I though this would be a good time to ask this. When the engine is cold, it has a really bad rod knock. After maybe 5 minutes of driving or less, it goes away(once it warms up). I was thinking, if I put a ticker 10W30 oil in, rather than 5W30 that it calls for, would that quiet it down a bit? I know it cannot be fixed, short of tearing the engine apart. I get that. I just want to do whatever I can to prevent/slow it down from getting worse, and possibly quiet it down. Also, would putting in a thicker oil damage the engine at all?

I asked my dad this...but he can't remember. Lmao. He used to know all of that when he was a mechanic. I guess turning 50 last week took it's toll LOL.

Thanks for any tips guys (and girl).

You are correct in your assumption that 10w30 would be better for your car than the 5w30. I would even go so far as to say if your engine is that worn, you would benefit from going to 10w40. When I built my 428 Furd engine, 55 years ago, I put 10w50 in it because I built it real loose for racing. JB

One word > Lucas.

It won't fix your problem, but it could help. Also gonna ask when's the last time you ran some Seafoam through the motor? Is it possible you have a knock from carbon build up or is this a down low problem? Get out the handy man's stethoscope (long screwdriver) & check the motor while it's running to determine where the knock is coming from. Put your ear to the screwdriver handle while it's on the motor part & check in various places. Since it's so new, a knock sensor should be putting your car into limp mode whether you hear it or not. How's it running when warm?

If the noise remains after using the thicker oil, it could be piston slap.

It sounds like the engine has a piston knock. which is due to excessive tollerences between the pistons and the cylinders.
as the engine heats up the pistons expands in the cylinder and that's why the knock go's away.
it's a very common problem in chevy engines from that era.

Rago wrote:How's it running when warm?

Perfect.

You have a 3.1 in that car correct? They all do that . We have had 3 of that Gen Monte here in the family from new, all 3.1, all did that. Its normal just use regular 10w 30 and it will be fine.

Thanks! Will do!

My aunt has a 97, also with the 3.1 and hers doesn't do it. Probably becasue it has 25 freakin thousand miles on it! Lol.

thicker oil and seafoam then if it dosent help time for a rebuild, also try running premium gasoline for a few tanks

After seeing some other comments & the conclusion that it must be a normal thing apparently, (Damn Chevy motors) I gotta repeat myself for sure. Run a bottle of Seafoam through it. 1/3 in your tank, 1/3 in your oil, 1/3 through your vacuum lines. Change the oil after driving it around for an hour or so & use a bottle of Lucas oil treatment when you change your oil. It's funny to watch the neighbors' reaction when you're revving the wee out of your car with the Seafoam & it's shooting out a black cloud of carbon but your car is gonna run twice as good after cleaning it out. Also, Lucas helps the oil "adhere" to the metal parts creating a constant film. Both products are awesome.

For SNG, a Vette getting Seafoamed: