FAQ: Supercharger Noise (Bad Coupler)

post keeps disappearing?? i swear im not trippin lol

hi not sure if this is da right thread to post in but its better i guess rather than making a new thread.. my 98 riv which is only at 97k miles started making this knocking noise:




i had a family-friend mechanic take a look at it and with da use of a stethoscope it was definitely coming from da supercharger. i know nothing about cars and he said most likely i need to replace da whole supercharger..

but what do you guys think, i didnt get a chance to read this whole thread i am just trying to ask right quick before i head to work, thanks in advance

**i replied in the supercharger sound thread but da thread itself kept disappearing?? idk shrug

do these replies have to me mod approved or do i have a restriction on posting or am i trippin lol

https://rivperformance.editboard.com/t3009-faq-supercharger-noise-bad-coupler?highlight=coupler

Read this thread. Chances are, it's the S/C coupler that's bad. It can be replaced in about an hour if your mechanic is any good.

the sound is not only when idle but when i drive though... i mean its only at 97k miles and im hoping its just the coupler but like i said my mechanic made the quick conclusion that i need to replace the whole supercharger unit. im gonna talk to him again but based on my video what do you think it is?? ive read 5 pages in and 5 pages at the end of that thread. ill try to get thru the whole thread when i dont have work but it sucks im not handy with cars myself so i can safe time (and money) especially when my mechanic is a busy man and only available once a week

One way to know if it's deeper than the coupler is to check the oil in the supercharger. This isn't so hard to do. If there is no oil in it, or very low, your mechanic could be right. If there is oil in the unit, it's very unlikely the blower snout bearing is failing. I've seen these superchargers run with little or no oil, probably for a long lengths of time by the time it's discovered.

The video doesn't sound like a worn coupler to me? It sounds like a rod knock? If you or someone else remove the belt from the supercharger, you can check if there is play in the pulley. You don't need to be handy with cars for this, you just need to have a wrench. If there isn't a considerable amount of play, it's not the coupler. I would then remove the SC belt from all the pullies it sits on and tuck it aside away from moving parts and start the car. If the noise is gone, your supercharger is bad. If it remains, the Supercharger is not the issue. A coupler rattle sounds a lot less consistent than that usually. Mine sounded like my car was grinding stones in the Supercharger and it came in surges, only at idle. It would take you a wrench and no more than 30 min to figure out what your issue is. Hope this helps. There are threads for belt removal.

When my coupler was bad, with the belt off the pulley, I could wiggle the pulley back and forth.

If your pulley is solid and doesnt wiggle, then its not the coupler.

It sounds like valve train noise to me....

FIX IT AND DONT GIVE UP!

there indeed was enough oil in the sc and we even replaced it. he let me use the stethoscope to hear for myself and it was definitely coming from the supercharger and not anywhere else... i wonder what caused this

charlieRobinson wrote:

When my coupler was bad, with the belt off the pulley, I could wiggle the pulley back and forth.

If your pulley is solid and doesnt wiggle, then its not the coupler.

It sounds like valve train noise to me....

FIX IT AND DONT GIVE UP!

-This.

Coupler is very quick and easy check. Pop the tensioner back with a wrench and take the belt to the SC off. Grab that pulley and wiggle back and forth.(Direction of belt travel.) If you have to ask yourself if what you feel is enough of a wiggle, then all you are feeling is gear play and its not your problem. If its the coupler you will wiggle it back and forth and say "well, holy crap, this is for sure what it is."

(And never listen to any mechanic who says you need a new blower. Short of the coupler there isn't much that goes wrong with a blower on a running engine. Coupler is a 10$ part. Not faulting the mechanic that recommends replacing the whole thing, its just not being familiar with these particular blowers.)

So the problem is my engine has been making a noise at idle. the noise stops when you give it some gas.
So I've been doing a little looking around at people that have similiar issues and it seems like the problem is the flex plate. I understand they arent too expensive, but i know that anything involving trans is a bit of a hassle doing by yourself. What do you guys think?

Flex plate??! That is NOT a common issue. Are you referring to the inconsistent rattle noise coming from under the hood at idle only?

If the engine is supercharged, you may be hearing the coupler rattle.  The coupler is relatively easy to do on the Series 2 M90 Eaton SC, less so on the Series 1 M62 Eaton SC.

I would say its almost like a knocking at idle, does the coupler usually do that?

AlienShoe wrote:

I would say its almost like a knocking at idle, does the coupler usually do that?

Yes it does, like a rattle. Very common.

my 97 has been in the family since new.ive had it for 3 years now.i know a good bit about these cars but cant get past this issue..noisy supercharger.I replaced the coupler and oil and no change.you can hear the noise through the air intake.when the car warms up the noise is mostly gone.if its cold it goes away around 1800 rpm...anyone have a clue if its the bearings in the supercharger??

Are you still using the original air box or do you have another set up installed liked a cold air intake? I have a cold air fender well intake thats 3" and when it's cold outside I can hear it making noise while it's sucking in air till the car warms up. Then it goes away.

J. Chris Davis wrote:

Are you still using the original air box or do you have another set up installed liked a cold air intake?  I have a cold air fender well intake thats 3" and when it's cold outside I can hear it making noise while it's sucking in air till the car warms up.  Then it goes away.

X2.  If the baffles in the air intake have been removed, you will hear that noise when cold.  It's sort of like a grinding noise.  It goes away when warmed up.  That is normal.

I have removed the air box.i had it gutted first but have heard the noise since.still running stock ac-delcos.cant stand autolite plugs.i work in the marine industry and see them fail often.

X3 on the noise. Both of my Rivs make that noise when first started, then it goes away. The noise is WAYYY more apparent on the '98 with the modified Intake. A bad coupler literally sounds like there's rocks in the S/C. It can also sound like a "rod knock". There's no mistaking the sound really.

X4. Even after I replaced the coupler mine still makes noise on startup.

X5

Doing anything to the air intake will increase noise levels, especially when cold. It does not mean the coupler (or anything else) is bad. There are a few benefits to keeping the car stock, and this is one of them.

LARRY70GS wrote:

If the engine is supercharged, you may be hearing the coupler rattle.  The coupler is relatively easy to do on the Series 2 M90 Eaton SC, less so on the Series 1 M62 Eaton SC.

M62 needs to pretty much be removed to replace the coupler. Just did it on mine a few weeks ago.

I replaced the SC snout with a rebuilt one, but rattle is still there. Probably not a total waste though because I noticed an oil leak a few times around the SC pulley, so at least I have new seals and bearings along with my new coupler. But I don't know how to eliminate the noise. Maybe I should look/listen closer to the other pulleys. Any thoughts?