The following description was offered by Steven in Houston when I called to report the same problem. If there is contamination in the fuel tank, it will get sucked against the filter screen inside the tank. More and more debris will accumulate against the screen, and the pump will get louder as fuel flow is restricted. When you shut the car down, even with the check valve, eventually the suction at the intake of the pump will fall off and some debris will float away agian loose in the tank, until the problem restarts next time. Basically the pump makes more noise when it gets warm it seems, that can be from a hot tank so the pump does not stay as cool, or from an overheating pump which is working too hard. If your car sputters or has low power when the whine gets bad suspect debris. Tom -----Original Message----- From: dmcnews@xxxxxxxxxxxxxxx on behalf of dadoc2791 Sent: Fri 2/29/2008 7:41 PM To: dmcnews@xxxxxxxxxxxxxxx Subject: [DML] Fuel Pump "Buzz" The other day I noticed that my fuel pump has begun making noise - a Buzzing sound, about 3-5 times as loud as it normally does when running. I found today that when cold, it's completely quiet. After being driven about 1-1½ hours, it begins getting louder. The engine runs perfectly at any speed so I know the pump is delivering ample fuel and pressure but I'm concerned about it. I've ordered a new pump from John Hervey and figure I'll keep this one as back-stock, in case it's needed in a hurry at some later date. Any ideas on what might cause this added noise to a pump that otherwise seems to be operating perfectly? Craig Werner 07181 [Non-text portions of this message have been removed] To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/dmcnews/join (Yahoo! ID required) <*> To change settings via email: mailto:dmcnews-digest@xxxxxxxxxxxxxxx mailto:dmcnews-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/