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View Full Version : Loud whine at startup?


ausie
08-04-2007, 10:05 AM
When leaving work last night, Once I started the engine I heard this horrible whine and got worse once I let the clutch out. Immediately shut it down and popped the hood so I can inspect all belts. Everything was fine so I started it back up and same noise. With the engine at idle and whining, I located the noise to be comming from the supercharger. Everything checked out fine. I will check the oil level in the SC gear box today to make sure that it was not just gear noise. I will also follow up on the inspecting the by-pass actuator to see if it closes under boost and opens at no boost. Engine is completely stock, no mods as of yet..... The noise was definately comming from the supercharger, not power steering pump or belts. Sure hope it is not the water pump since it is probable that if it made noise to migrate up through the block and appear it is the supercharger. It did not make the noise after driving for an hour to get home, just that one time.....

JymBart
08-04-2007, 12:03 PM
Are you still using all the stock pulley's? The stockers have a poor history, .. not saying this is your problem but do not rule out a pulley as your cause of the noise.

JymBart

ausie
08-05-2007, 11:42 AM
Yes, all of the idler pullies are stock. I have heard some bad pullies before and it did not have that type of sound but will not rule it out. Unfortunately the sound was definately comming from the Eaton. It sounded like a one of those large Weiand roots blowers at low RPM. At first I thougth it was the belt but that looked in good condition. When I went to inspect the oil level in the supercharger, I notice that the upper support to the pulley cover was cracked so the cover was only held in place by the two lower bolts (now removed entirely). After instpecting fluid level of the supercharger, there was alot of pressure released once the fill bolt was loosened. The gear box has plenty of oil in it (probably too much) considering the amount of flow so I recapped it before any more would flow out. It still makes a mild noise at idle but sounds closer to normal now. Not sure if that was the root cause or if that was the problem in the first place. I suspect that the bypass valve may not have been open when that occured. Vacuum lines are fine at least I cannot detect any leaks. I may experiment with it and see how it sounds when the blower is not bypassed which may give me a clue to what may have happened.

ausie
08-06-2007, 08:02 AM
Further investigation: pulled and plugged the vacuum line that connects to the upper post on the boost bypass actuator and did a start up. Bingo, same exact noise. At least it was repeatable and not some mysterious random occurance to have to wait for it to rehappen to find out what was what. Movement of the actuator seems okay. Any thoughts as to why the valve would remain closed at startup? I did not remove the throttle body and intake plenum to inspect the valve (it has been over a year since I did a thourough cleaning. When I had the spark plug problem a month or so ago, the intake and throttle body was extremely clean, even had a look through with a flashlight and did not notice any varhish or carbon buildup (which was surprising, most likely due to the change in oil I am now using, Royal Purple 5w-40). If this issue happens again I may pull the intake plenum off and inspect the valve but at this point I do not think that is necessary. Since the actuator connects to a solenoid controlled valve (appears to be two position) perhaps that is sticking and preventing bypass valve from openning.