Earlier today i changed my oil. my 04 montecarlo 3.4L sais to use 5w-30 but i just recently traded a different vehicle for this one and this one has 116k miles on it. the people at nappa auto parts told me to get 10w-30 with 75k + mileage vehicle for it so i got it now i go to school at boces for automotive but they dont really teach us about oil. so should i have stuck with the 5w-30 oil or was the 10w-30 oil with high milage protection a better option. my step dad incists that the 10w-30 is bad for my car and the 5w-30 was what i should have gotten
now when i drained the oil it was black as tar and it had a burnt smell on it so whoever had it b4 me was bad with oil changes. but i didnt find any metal in the oil so not to terribly worried

 

First, 10w-30 or 5w-30 does not make a huge difference on these cars. The earlier generation of GM's 60 degree engines (the 3100) used 10w-30. As a rule of thumb, I try to stick with what the manufacturer recommends. But you have no reason to dump the oil because of 5w vs 10w in this case.

As for the high miles protection stuff, I am honestly not sure how much of that is marketing hype vs something worth while. I know a good amount of 3100 and 3400 that have crossed the 200K marker and still run great. I had once of them (a '94 Grand Am) and I ran plain conventional oil in it, no big deal and sold it 9 years later with 215K on it! Engine and trans ran great!!!

Now, if the oil from the last owner came out that bad, I will recommend that you DO NOT use a motor flush product (as that has the potential to un-lubricate bearins and such inside the engine). But, you may want to give it another oil change in 1000-1500 miles, see how the oil comes out, if it's still bad, repeat until it seems what you would expect oil to look like at that mileage.

Also, I would consider dropping the trans pan and changing the fluid and filter there too.

Here's a lot of other things to consider at around 100,000 miles:
https://montecarloforum.com/forum/fw...0-miles-46078/

 

if it's warm outside, it really doesn't matter...the 5w or 10w just means the oils viscosity in the winter time....the W stands for winter...the oils ability to flow at 32 degrees...so, let's say it's 60 degrees outside, it doesn't matter if you use 5w or 10w...

 

I was never a believer in motor oil additives....

Until I hit 100k on My Monte...

I use 5 w 30 and add 1 quart of Lucas High Mileage Oil additive...
at every oil change... all my vehicles that have 100k or more I use it in them.

My wifes 2003 GMC Sierra custom only has a mere 42,000 miles so it will be a while before I will also use Lucas in it.

 

i never believed in the additives and stuff for your car...but i will have to say, that i do believe in the lucas products...they do actually work...the lucas that you are using is more of an oil stabilizer than an additive though...it keeps the oil viscosity much more consistent and makes it more resistant to thermal breakdown...even as a service manager i do recommend lucas products to some of my clients depending on what i know will help...

 

5w-30, 10w-30 it's all the same.

I run 5w especially in the winter. You are perfectly fine

 

As stated above, 5W or 10W...doesn't matter. Especially now that it's getting warmer out.

 

Thanks everyone! I was gonna change my oil around 1500 miles, im hoping to get adleast 200k miles outa it.
Next Car is a DODGE STEALTH! gonna put upwards of 100k into it
gotta make it faster than a lambo maby even a bugati lol i can dream cant i!

 

Agree 5w30 and 10w30 don't matter much as its only on a cold start up with how thin/thick it is to flow through the engine until it warms up. The 10w30 on a cold start will have a little better oil pressure than the 5w30.

Now same goes for the second number the 30 part. This is oil viscosity when warm. I've noticed it's better to run a 40 in the summer as it keeps a little better oil pressure at idle. I don't drive turbo monte in the winter so all she ever gets is rotella t6 10w40