2002 Impala 3.4 engine

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I have a Chev. Impala, 3.4 engine with 120K miles. When I start it up I get a lot of noises, but after a couple of minutes you can't hear it run if you close the hood. Still gets 25 mpg on a road trip. I want to change the oil and am thinking about Pennzoil HM, but I don't think it is a blended oil. This motor has had oil changes around 4k or 5k its entire life. Should I just use the regular Pennzoil or the HM, or the Platinum?
 
The noise is normal in these 3.4L engines. It's the same story in my 2005 Impala with the 3.4L engine. Run whatever you desire and 5k intervals is fine. Really, depending on your driving style, you probably could extend the intervals out as well.
 
A heavier oil won't be of any benefit really. It's just a natural occurrence in this engine. FWIW, I have ROTELLA T6 5W-30 in it and that noise is still there, as it's been for the last 3 years I have owned that car.
 
Yep, the clackety-clackety piston slap noise seems par for the course on the Chevy V6 on cold start up. IDK about the 3400 and prior versions, but GM brilliantly installed under-piston oil sprayers on just 2 out of the 6 pistons for whatever reason in the last version of that engine series, the LX9. I'm thinking the roots style oil pump can't support all 6 sprayers....
So yeah, it's normal.... "GM normal"
 
Originally Posted By: PeterPolyol
GM brilliantly installed under-piston oil sprayers on just 2 out of the 6 pistons for whatever reason in the last version of that engine series, the LX9. I'm thinking the roots style oil pump can't support all 6 sprayers....


It has 3 Nozzles.....Each oils 2 pistons. No need for 6 separate ones on a 60 degree engine as the banks are so close to each other.
 
I have basically the same engine, a 60-degree GM V6, 3.1L. Last oil change I performed on it was 90k km's ago (56k miles) / 10 years. Had the oil pan off 2 years ago and everything was nice and clean. Esso XD-3 0W-30 synthetic.

So run long drains in that sort of engine with confidence, and of course, keep an eye on coolant leaks.
 
Originally Posted By: clinebarger
Originally Posted By: PeterPolyol
GM brilliantly installed under-piston oil sprayers on just 2 out of the 6 pistons for whatever reason in the last version of that engine series, the LX9. I'm thinking the roots style oil pump can't support all 6 sprayers....


It has 3 Nozzles.....Each oils 2 pistons. No need for 6 separate ones on a 60 degree engine as the banks are so close to each other.


Interesting. Not sure about the other 3x00 engines, but the LX9 3500 specifically has only 2 sprayers- it's actually a one double-ended sprayer serving Cyl 5/6 only (the rest of them are not simply just out of frame;)) Never seen this in any other engine before... it's weird
oilsquirter3500.jpg


But if the noise is common across all 60 degree'ers then it's probably not the odd sprayer config
 
I'm at 160k miles in my Alero with the 3.4 and its run lube shop conventional for all of its 16 years. When I did the LIM gaskets and valve cover gaskets, I cleaned the gunk under the valve covers which was not unsubstantial. I don't think the PCV valve was ever changed. I run PYB now and a Fram TG filter and it runs great with new plugs, wires, and very quiet with new tensioner and pulleys.

Its been several oil changes since the switch to PYB and the view down the oil fill hole is much improved. The years of bulk Castrol GTX left gold deposits and the lack of PCV valve maintenance probably contributed as well. Solid engine and transmission unfortunately with very poor build quality in the rest of the car.
 
The 3.4 was known for cold startup clatter. It is caused by piston slap, and when the pistons warm up, they expand and fit tighter in the bore and the noise goes away. It doesn't really hurt anything, they will run a long time.
The main issue with those engines was the lower intake manifold gaskets. Keep an eye out for coolant leaks or milkshake looking engine oil from coolant contamination.
If you ever have to replace them, felpro makes an improved "ultraseal" kit that will last much longer than the original style.

Honestly, other than the intake gasket issue, they were a good engine. Good gas mileage for a v6 and decent power. Seen many of them go over 200k easy with proper maintenance.
 
That has been my experience with this car, the motor and tranny are good for a lot of miles, but the rest of the car, it leaves a lot to be desired as far as build quality goes. I have had to get the intake manifold gaskets replaced at 53k. This was my mother's car, and she didn't drive it much, and never changed the anti freeze in it. It came to me b/c my mother was sick and she wanted me to check her car out b/c she was smelling anti freeze all the time. It was leaking out and getting on top of the motor, and the oil got in the radiator, etc. It was a mess but the car only had 53k miles on it when it was 11 years old, which was about the time I started driving it. When my mother passed away 5 years ago my Dad said he was going to quit driving and gave the car to me. I thought it was worth fixing with only 53k on it, so I took a chance on it. I have had to fix a few things, mostly due to it sitting all the time, IMO. It has really good power and pickup, and it gets mid 20's MPG, which for a big car like an Impala that was pretty impressive I thought. I have 120k on it now, and it still gets mid 20's mpg. thanks for all the input.
 
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