Oil Recommendation 03 Impala 3.4L

[JustinMP]

Hello everyone,

I've been browsing the forums for a few days now... reading up on different brands and mixes of motor oil. I never knew it could be so complicated. So here I am, about to ask for some recommendations for my vehicle.

I have a 2003 Chevrolet Impala with the 3400 SFI engine. It has around 88,000 miles, and I live in upstate NY where we can have some pretty cold winters. I tend to drive easy, aside from the occasional bout of road rage (which still isn't very bad), though I do drive the speed limit, I just take my time getting there. Short trips usually, 6-10 miles one way twice a day. Sometimes I go on longer trips (a month ago went 4 hours.. highway). I don't do very much stop and go city traffic.

My car's engine is known for LIM gasket problems... which I did end up having not too long ago. My dad and I replaced the gaskets and replaced the coolant with non-DEX stuff. Unfortunately, my dad took a few weeks to complete the work (yeah..) and my engine did NOT sound good upon starting it back up (took time to get the oil pumping). Ever since then, I've had "piston slap"? only when the engine is cold, a very slight tapping sound that increases with RPM. Not a big deal, goes away when warm.

More recently, I decided to try an Auto-RX treatment... since when I first got my car, it wasn't kept up as well as I would like (the oil barely registered on the dipstick when I first took the car), though it has had regular oil changes in the past and just got low for some reason. It doesn't seem to burn very much oil at this point, but I think when it got low there was some sludge buildup so that was why I decided on the Auto-RX treatment (also to see if I could get my engine to quiet down).

Unfortunately, my engine has gotten LOUDER about 1500 miles into the treatment with Auto-RX (where I am now), and has developed a kind of knock, which almost completely goes away when warm. Engine seems to run fine, and is very reliable. This knock did not exist before the Auto-RX treatment, and may be a side-effect of the brief dry-start after the LIM gasket replacement job. I'm hoping it goes away after I finish the ARX treatment.

So, down to what oil to use... right now, I use NAPA brand oil (5W-30) and NAPA Gold oil filters, since my dad has an account with NAPA and gets discounts (he races at a local raceway, builds race cars, etc). I know NAPA oil = Valvoline... but Valvoline seems to have only a mediocre reputation on this board. My owner's manual recommends ONLY SAE 5W-30 oil.. it doesn't mention any specific certifications.

Is there a better oil for my vehicle, or should I stick with the NAPA stuff that I've been using for a while? I tend to change oil at 3500 mile intervals, just out of habit. I don't have any brand preferences or synthetic vs dino preferences. From what I've been reading, good dino oil is comparable to synthetics and is good enough for normal use. So, I'd appreciate any suggestions and if something is missing, let me know - because I wrote this at 1:30 AM

Thanks!

 

[Colt45ws]

I did the Headgaskets in my grandparents 2001 Montana with the same Engine. It clattered a little as well, but in my case it was doing it prior to the headgaskets. I believe in my case it was the lifters.
http://www.youtube.com/watch?v=DN_Rz19lHdc
I ended up converting it to 10W30 Rotella T5. Sounded better, but only got one run with a couple thousand before it was sold.

After rereading it I have to ask, how loud is it and how loud was the first start up and what did it sound like?

 

[umungus1122]

With a 3500 mile oci, any current API 5w-30 should be fine.

 

[JustinMP]

Ah wow Colt45ws, that sounds pretty close to (if not exactly) what my engine sounds like when cold. Sound goes away when warms up though (for the most part). But that sound didn't become noticeable until after starting the ARX treatment. As for what it sounded like on startup... it sounds like you'd an expect an engine with no oil to sound like, until about 5 seconds when the oil pump got things lubed again and it went away.

And umungus1122, I wouldn't mind extending the interval if possible. During the college months it gets driven less though so it might be best to just keep that. Even with the 3500 OCI though, would there not be any oils more suitable for the colder winter temperatures, or one that might make the engine run quieter? Probably a stupid request on the last one, but hey.

Thanks

 

[Klutch9]

For the GM 3100 and 3400 motors (essentially same motor with different displacements) piston slap on startup is actually normal. I think the engines were designed that way to reduce piston ring to cylinder wall heat. I know that on later models, sound insulation was added somewhere in the motor and/or engine bay to reduce the noise. My dad has an earlier model 3100 in his '95 Cutlass Supreme and it piston slaps a WHOLE bunch on a cold start, and it goes away as the engine warms up. He recently did his LIM gasket at around 170,000 miles, and to this day his car still burns almost no oil using SuperTech 5w-30 dino for 5k-6k OCI's. Don't worry about the piston slap, and use any oil for a 5,000-6,000 mile OCI and you'll be golden.

 

[JustinMP]

Thanks for the reply, Klutch

. Glad to hear it about the piston slap - I have heard of this before, but I was just a little concerned because it became more audible during the Auto-RX treatment. Since the general consensus so far is to just use any oil and up my OCI a bit, I've done a bit more searching around and am thinking about buying Valvoline NextGen MaxLife 5W-30 since there's a good rebate on it and I've read that the additive package can be a bit stronger in the genuine Valvoline oil VS NAPA. That, plus I've never had a problem with my current oil and I was just wondering if there is something better. Looking forward to my next oil change, starting the ARX rinse phase. Thanks again.