Engine Knock. Is It Rod Bearing or Lifter?

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These things are famous for cold piston slap, but that doesn't sound like what you are describing to me. Your aunt's car does though.

I've had a couple and currently still own one, the 2000 Lumina, at cold start it sounds like it's going to disintegrate yet quiets down nicely in just a couple minutes. Still runs great. Leaking coolant yet again though.
frown.gif
 
Ah man that sucks! How many miles on your Lumina? There great cars too if well taken care of. Great motors too. Is it leaking from the famous lower intake manifold gasket? I replaced mine with the Felpro problem solver rubber/metal gasket. Costed a little more but well worth having to take it back apart. That's odd because mine doesn't have piston slap. Mines the LG8 or Vin J. I heard somewhere that they were the worst for piston slap.
 
Those cars are major flywheel crackers. I've worked on many of them brought to me for rod knock that turned out to be cracked flywheels. Sounds exactly the same, and from the same area of the engine as rod knock.
 
The absolute cheapest thing to do is to up the oil pressure and volume.

Right here on this forum, motor oil university classroom 105: http://www.bobistheoilguy.com/motor-oil-105/

Ferrari engineers say that you need 10 psi oil pressure for every 1,000 engine rpm, peaking 75 psi @6,000 rpm. This formula works in all situations. Do you think Ferrari engineers know anything about going fast AND remaining dependable?

My 3.8 Buick has about 55 psi oil pressure when hot and running 60-70 mph; about 22-24 psi when hot idling, up to 62 psi when cold started. I have a bypass filter setup and BEFORE I installed the turbo oil restrictor jet: http://www.ebay.com/itm/331078883470?_trksid=p2060778.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I can tell you from personal experience that running the bypass wide open caused a drop in my oil pressure of about 25%, down to about 40-43 psi on the highway. When I put the restrictor jet on and RESTORED my oil pressure, the engine sounds a lot quieter.

I honestly don't know if it is the same for your 3.1; but on my 3.8, you can simply change the oil pressure bypass spring, piston, and gasket; this will increase the oil pressure significantly. I don't have any problems, but I'm going to put this on my own just to sleep peaceably. I already have the parts. For $27.99, it is the cheapest possible thing that MAY help. There are instructions online and even pictures:

http://intense-racing.com/Merchant2/merc...ode=3800_Engine
http://shop.zzperformance.com/store/p/95-Oil-Volume-Kit.aspx

Regarding bearing sizes; factory replacement sizes, unless you plan to remove the crankshaft and have it turned. Good Luck! Keep us posted!
 
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I can tell you exactly what it is.

It's time to trade.

Get it nice and warmed up and get it to the nearby Carmax.

Leave with a check in your pocket.
 
Ok so 40 psi cold idle is Okay?? I know you sent me a like about the bypass thing, but won't bypassing or whatever be like the oil not being filtered, or am I just dumb? Haha
 
I tell you what, I would love to trade, in fact, I can buy a new (used) car now If I wanted to. But I really do NOT want to get rid of this car. It belonged to my grandma. She bought it new and had it until a couple years ago. It has a lot of sentimental value to it. This might sound silly to you all, but I'm kinda attached to the car! Oh well if I'm weird haha.
 
Hmm. I've never heard of the Malibu's cracking flywheels bad. I don't think that's what it is though. I'm no expert, but it just sounds like an engine thing. You'll know what I'm talking about when I get a video on here somehow haha. By the way, you have any idea of how to get a video on here? Or will I have to post it to YouTube then post a link on here?
 
Post a video with the sound it could be piston slap which could be harmless and it can also be carbon build up... if you were "flooring it" and it was a rod making that noise the rod would have probably removed itself from the crank by now. Those engines are good motors overall.

Play the video and comment on engine temp if possible.
 
Originally Posted By: ChevyGuy3100
Ok so 40 psi cold idle is Okay?? I know you sent me a like about the bypass thing, but won't bypassing or whatever be like the oil not being filtered, or am I just dumb? Haha


Ihatetochangeoil ...is talking about the oil pump bypass pressure.In other words a weak or leaking oil pump.This is your cheapest-best hope.You can check for a sludged oil pickup while you're in there.
 
Originally Posted By: ChevyGuy3100
Hmm. I've never heard of the Malibu's cracking flywheels bad. I don't think that's what it is though. I'm no expert, but it just sounds like an engine thing. You'll know what I'm talking about when I get a video on here somehow haha. By the way, you have any idea of how to get a video on here? Or will I have to post it to YouTube then post a link on here?


I'm telling you. Check that cheap stamped flywheel. It will sound exactly like rod knock. Not saying that's what it is, but check it.
 
Originally Posted By: DoubleWasp

I'm telling you. Check that cheap stamped flywheel. It will sound exactly like rod knock. Not saying that's what it is, but check it.


I already told him once. There is virtually no way to tell the difference between a cracked flywheel and an "engine knock". Unless you inspect the flywheel.
 
It's not a rod knock - they don't quiet down when you run them hard. Leave the bearings and oil pump alone. My vote also goes to cracked flywheel.
 
Rod bearings or cracked flywheel, it sounds like ChevyGuy3100 is going to be spending some time under his car. You gotta take it all the way apart to properly fix either. Yes, he could replace the rod bearings with the engine in the car, but they would probably just go bad again due to the worn crank.
 
I looked at the flywheel through the hole, and turned the motor over with ratchet, I didn't see any cracks. I looked for a good hour this morning and didn't even see a hairline crack. I got video and I'm going to try to post a link. 2 videos actually. One on cold start and one when I got back home just now.
 
Hey thanks! I looked really good at the flywheel this morning. Didn't see anything. It looked fine. But I guess I couldn't tell until I took it off. But I've heard a cracked flywheel before. This sounds nothing like it. I've got a couple videos. I'm going to upload to YouTube then post a link here.
 
Yes both of you told me. But I couldn't do it until this morning. I looked for a good hour through a hole and didn't see anything. It just doesn't sound like a flywheel to me. I've heard one before. This actually sounds like it's in the motor. I'll let you be the judge once I get the video link uploaded
smile.gif
 
Originally Posted By: Ihatetochangeoil
I have a 2000 Lesabre with a 3.8 V6 in it; 195K. Also a 2004 Impala with a 3.4 V6 in it; 150K. Original everything. You have the same engine. http://en.wikipedia.org/wiki/Buick_V6_engine


These two cars' engines are completely different. The 3.8L belongs to GM's 90 degree "Buick" V6, which, in my opinion, is one of the best engines ever to be put under the hood of a FWD car.

The 3.4L and 3.1L are both in GM's 60 degree V6 engine family which debuted in the early 1980's when GM needed something compact to put in small FWD cars they were introducing at the time. While not exactly a thriller of an engine, they have been around forever and are as reliable a workhorse V6 as they come. For years these engines were plagued with intake manifold gasket leaks which would grenade an engine in short time (unless caught and repaired in time), but other than this anomaly, they were good, rock-solid engines.
 
Yeah I knew the 3800 was different than my 3100. I think he was talking about his Impala with the 3400. They are the same motors other than bore size I think. I agree with you on the 3.8 Being a good engine. Somebody in my family has a 95 Buick Lesabre with that motor. Its strong, but has a few problems that can easily be fixed.
 
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