Knocking Sound?

Hi...I changed a timing chain at 143K thinking that was going only to hear the noise again at start up! It was the bearings at the back of the alt! $99 and a 25 minute job to change!

Hello all, I have 95 Riv S\C. And I am unsure unsure which way to go. Maybe you knowledgeable guys can help. I don't if it will be easier to rebuild the motor I have ( it has 100k miiles) or TRY to find another engine. As of now I haven't found one here in NC.


Thank you all for this great site and all your help,Daryl

3800 engines are a dime a dozen. You can find a decent used one for a fraction of what you'd pay to have it rebuilt

car-parts.com FTW

DCanady, tell us more about your problem. Is the engine knocking, or is the supercharger making noise? You may not need to replace the engine, it's unusual to need one at only 100k miles.

Thanx for the replies guys. Yes it is the engine knocking, sounds like a main bearing. I have had 2 mechanics listen to it and they both agreed that it sounded like a main bearing.

Just get a used low mile, take the easy way out. Only do a rebuild if you are going to do a performance build or make something unusual, otherwise it's not worth rebuilding. Just buy used low mile.

Ok I have a 95 Rivi with the stock series I. She's been parked for about 2 months due to a hard knocking noise comming from the engine that I can't seem to track down. For a while after I parked her she would still start but she wont anymore. Thats kind of whats makin it hard to figure out. The engine still cranks without hesitation though. I thought maybe I broke a connecting rod but I dont think the engine would try to crank so easily with a broken rod. After a few days of her sitting and not starting I noticed she began to leak oil so I got under her an took a look to see what I could see. I had already needed a valve cover gasket so it makes it hard to determin where the oil leak was coming from but I did notice that there was a build-up of oil around the oil fiter. So my next best guess was the oil pump but I didn't want to just go change the oil pump and that not be the problem seeing how I dnt have a lot of money to spend on her. I know It's pretty hard to give a diagnosis on a problem and not be present to see for your self but I'm stumped. I dont have a clue as to what to do next. I would greatly appreciate if someone could way in on my situation and hopefully give me some form of advice. Thanx

Have you checked the harmonic damper/crankshaft pulley assembly to be certain that it has not seperated. I had this happen on my '89 Riviera shortly before I traded it in. (I fixed it first though.) It might be bad enough that it beat up your crankshaft position sensor??....so no startup.
Now you may have an internal reciprocating problem. But like you said, kind of hard to diagnose online.

Best of luck.

when mine went bad (rubber tore open) i had major knocking noise from that side of the motor, then oil leak from the front main seal being beat up.

wow I realy hope it isn't that but I'll definetly take a look. If it broke my crank sensor, wouldnt that stop the engine from rotating much when I try to start her though?

superchargedmoney wrote:

If it broke my crank sensor, wouldnt that stop the engine from rotating much when I try to start her though?

No, it will crank over (as long as battery and starter are good) but won't start if the sensor is broken.

I bought her from a friend who I spoke to last night and told him about my problem. He said he had replaced the harmonic damper and crankshaft position sensor not too long before I purchased her but I don't know if he got the parts new or if he went to the yard to get them. So It doesn't realy change anything I'm still gonna take you guys advice and check it out. Thanx for the help. I'll let you guys know what I find.

fyi i bought a new balancer from advance auto and it broke within 6 months. got another one from them and it too broke within the year.
get a GM harmonic balancer if you do replace it.

Just got done gettin dirty and come to find out you guys where right. The harmonic balancer was tore to shreds. When I pulled it off it fell to pieces. You know how much the GM harmonic balancer costs and where I can find one?

dealership has it for ~$200
rockauto might have one. DO NOT get it from the auto parts store, their quality control obviously sucks.

Nice job helping to identify the problem, guys!

Ouch that $200's gonna hurt. I haven't been working steady for about 6 months now. I think just for the sake of my pockets I'm gonna have to go with Pep Boys. They only wnat $89.99. I'll just make do with that and worry about a new one when I get back working. Thanks for all the help!!!

read this
and tell me you want to go through that hassle because you went with a defective part.
BOTH of the harmonic balancer i bought at advance auto broke within the year. BOTH times did extensive damage to toher parts of my motor. would have cost me $1000's had i not been able to do the work myself.

if you cant wait for the shipping gmpartsdirect has it for $111.

That $111.00 sounds very reasonable. Do you have the part #?

Go to the website, plug in your car info and look it up.
They don't always list things by p/n.
Then order, pay for and wait for the UPS truck.

ok thanx

1Bad98Riv is back in action. took it down to the cruise spot tonight. did a couple 1/2 throttle pokes.. kinda scared to get on it lol..

NEW DEVELOPMENT though.. It has a rod knock sounding thing.. i can't tell if its a lifter tick or a rod bearing (rod knock).. maybe ill shoot a vid... anyone know of the easiest way to check if its a lifter tick or what the knocking noise could be?

98riviera98 wrote:

1Bad98Riv is back in action. took it down to the cruise spot tonight. did a couple 1/2 throttle pokes.. kinda scared to get on it lol..

NEW DEVELOPMENT though.. It has a rod knock sounding thing.. i can't tell if its a lifter tick or a rod bearing (rod knock).. maybe ill shoot a vid... anyone know of the easiest way to check if its a lifter tick or what the knocking noise could be?

I think putting a screwdriver on the VC and putting the handle against your ear is a good way of verifying valvetrain noise, although I've never tried it myself. Make sure to stay clear of belts and the alternator blade

Piston / rod noise is 2X faster then valve noises , lifter will be more of a tick even at idle , a rod will usually increase its amplitude with rpm.

By any chance did the oil pan get dented in the tranny boom/repair?

98inSFl wrote:

Piston / rod noise is 2X faster then valve noises , lifter will be more of a tick even at idle , a rod will usually increase its amplitude with rpm.

By any chance did the oil pan get dented in the tranny boom/repair?

it is more of a slowish tick at idle.. ill take some vid tomorrow. and hopefully you can hear it in the vid. Nope it didn't dent my aluminum oil pan on my L26 block.