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Supercharger on Buick Park Ave Ultra

I have a 1993 Buick Park Ave Ultra with 127,000 mi and it has a rattle like noise in the engine. I took it to the mechanic and he said it was the supercharger and that if that went out the car would not run. I would like info on the supercharger, eg. is it critical for just riding around town and exactly what it does, and how expense is it to fix/replace. I want to sell this car, but will donate it if this problem is too expensive to fix.

Superchargers do nothing until the throttle is open at least half way…Less throttle than that and you are running intake manifold vacuum and the blower is not in the picture.

However, GM designed the puffer as part of the engine so simply removing it, while possible, would require major plumbing changes to get the belts and air-filter hooked up properly…Using the hardware from a similar but not supercharged model would simplify the process and would require a few hours in a salvage yard rounding up the parts you will need…

I don’t know a whole lot about the specifics of these engines, but the compression ratio might be slightly lower than the version w/o the supercharger. Might be a dog if adapted to run without it.

If the supercharger is actually rattling then maybe it’s low on oil. I would hope the oil level would be checked.

It would also be interesting to know if this rattling is present all of the time, only on acceleration, or whatever.
Just wondering if this rattling is a pre-ignition rattle, piston rattle, or what have you.

You can always slip off the belt for the supercharger and turn it by hand to see if it is showing signs of bind by hand.

An alternative to look at is maybe the bearing on the AC clutch bearing is bad.

I have a 2004 Monte Carlo with pretty much the same supercharged engine. At 45Kmiles the belt tensioner has siezed causing the belt to be overly stiff. What happened next is the AC bearing took the abuse that the belt tensioner is supposed to absorb. This beat the bearing out on the AC. Now the noise was what I thought a bad supercharger until I looked around. I was able to find a replacement on that was very simple to change just the pulley and bearing assembly.

On a cold motor, reach down below the coil packs and see if there is any side to side wobble you can create on the AC pulley. Or even just look down at the pulley while the engine is running to see if it is moving around a bunch.

And yes the compression ratio is a 8 to 1 instead of the 9.5 to 1 on the non-supercharged cars. That will result in a very weak car if you disable the supercharger and replace with a non-supercharged assembly. A possibly alternative, is to take the belt off the supercharger and find a way to block the bypass valve located on the front of the engine at the supercharger base in the always bypassed mode. That would be when the vacuum has pulled in the actuator for reference.

I’m wondering of the rattle is pinging. Are you using premium gas? If not, try a few tankfuls and see if that affects the noise. Perhaps your shop was telling you that the supercherger was cauing the noise becaue if the compression increase and pinging rather than because the noise was coming from the supercharger.

Answer OK4450’s questions and we’ll be able to helpp you better. Pinging is that preignition he was wondering about.

The noise is probably the supercharger. There is a coupler between the front pulley assembly and the body that bolts to the intake manifold. Over time, the cog holes that couple the pins on these two parts become worn, thus the sloppiness cause the metal gears to raddle. The kit with the charger oil and up graded coupler is under $50. If the bracket that has all the belts, pulleys etc is a two piece bracket, the fix is simple to remove the front of the supercharger. If it is a one piece bracket the job is labor intensive as there is a hidden bolt under the power steering pump. In this case, the one piece bracket
does not have to be removed but all the bolts have to be loose enough to back it away to pull the pulley nose part out. All this can be done from the top of the engine bay.