I recently picked up a 98 v6 5 speed from a guy who thought he had a bad motor. His reasoning for believing this seems to be a squeaking noise coming from the car that he thought was a rod bearing.

I did some quick troubleshooting and found the noise to be coming from the alternator, so I have a donor alt. I'm gonna take apart and put in this car, but there's also a really loud and rather hard vibration that occurs when trying to drive it or just reving it up out of gear.

I know the crank pulley tends to wear out over time on gen III v8s so I figured it may be the same here. I got another crank pulley from a 2000 v6 but I haven't put it on yet.

curious to know if anyone has had such a thing and if this is at all common among v6s?

originally I was going to part this car, but that was when I thought the motor was bad. Now I'm thinking about selling it whole.

 

Never heard of a pulley going bad on a 3800. Sound like maybe the guy might have been right.

 

well, at 202k miles I'm not 100% sure he wasn't. I still have someone interested in the car as a whole, but I guess I was kind of hoping I could tool around with it a bit.

It idles quiet,and can rev up fine. It has a CEL I haven't scanned yet. It is skipping but not constantly, only every now and then. It revs quick and easy. I am seeing a telltale sign in the oil gauge however in that it flickers when you agitate the rpms. It's a consistent 60 at idle, but rev it and it doesn't smoothly increase, it jerks up, then back down.

It has fresh oil and a new filter on it from the previous owner, so they have done SOME troubleshooting to it to come to this decision, but I drove on it a good bit since I got it, drove it on and off the trailer, last guy was driving it to the store n things as is.

these 3800s must be tough if it can go this long with a bad rod bearing.

 

if it turns out to be a bearing you can get 3800s a dime a dozen and there in just about every gm car (buicks and pontiacs mostly) theres a sticky here that tells you what you need to convert a FWD motor to your car

 

oh yea, I walked past probably 2 dozen 3800s in the junkyard sunday.
I only paid $550 for the car, had to rent a trailer @ $65, so if I get $700 out of it I think I'm fine. I don't think I can get more than that as a whole car, and I don't think putting more money into the engine will improve things in this case. (the car's pretty rough all around. A good coat of primer would clean it up a lot tho cos the body is straight, the interior's just nasty.)

 

codes P0107 and P1107, both deal with MAP. Could be bad sensor or a vacuum leak.

now that the alternator is quiet, there is a noise at idle.. best way to describe it would be "marbles."

I think we do have a bad rod bearing in this one. Well shoot. I'd hoped to fix this car a bit, tool around with it, get better with manuals and then sell it to a driver.

oh well.. car for sale! lol. $700 firm.. if my first buyer falls through that is. (if he does I'll put up a formal for sale listing DW. and if that doens't go I'll part it.. so again DW.)

thakns for the help yall!

 

Normally when someone says "marbles" it ends up being the water pump. Sounds are always hard to describ. I have sent way to much time being told what a sound is "like" and about 50% of the time it ends up being nothing like I thought.

I could see where a person that had a failing water pump, noise altenator and a vacuum miss could think it was a bad motor. Maybe you should try it without the belt on. Do not run it for more then 30 seconds. Rod bearing(s) should sound like somene is tapping or smacking something with a hammer.

 

When you start the motor there is a very brief (~1-2 seconds) where you can hear a bit of a knock in the engine, but it's not all that different from the piston slap sound my ls1 makes when it's cold and it doesn't seem to come back.

from there it's an inconsistent, rolling/low pitched bearing/marble sound. It's not a loud banging noise or anything of the sort.

We haven't ran it long enough to open the thermostat since I got it, it's pretty low on gas and if I'm gonna part it I don't want to put more in.

if it were the water pump that still wouldn't explain the loud vibration when rolling it at 20+mph. (though to be fair, there's a lot of other components in a powertrain than the engine that could do this I'm sure.. just that it does it with the clutch in as well when rpms climb.)

so we have a low pitched rolling marbles inside a metal casing sound, a weird vibration, and a slight knock when the engine starts are our knowns. I can't drive the car on the road cos it has no tag, and I can't register it with the 2 codes it has, so my drive time in it will be severely limited to driveway and MAYBE I can squeak it around the culdesac once or twice, which lets me get to 3rd gear, but that's all I can do.

Is it uncommon to have rod issues on 3800s? I mean I'd ASSUME that a v6 car wasn't drag raced or something.. this car looks like it was just driven until the wheels fell off so to speak. Maybe lack of maintenance?

guess the only way to know for SURE what's going on would be to tear it down and have a look, but I'd rather not. (man.. and I thought ls1 guys had it bad on spark plugs.. these cars look IMPOSSIBLE to change the plugs on!)

also, we did run it without the belt on a few days ago. It still had some noises, but I can't tell you now form memory if they were exactly the same noise. I THINK it was, but i'm not sure. Certainly it was making SOME sort of noise.

 

if I have time I can try to make a video, but I dunno how well it will be picked up by my camera.

 

Rod is not super common but it happens, I think more from high end deceleration or over reving on a higher miles motor. These bottom ends are insanly strong when everything is work right. I have worked on a lot of cars that needed crank kits and the vibration you are talking about does not fit with that. But the combination of noise and virbration has me wondering about the balancing shaft.