We've acquired a strange noise lately. It's a 3.8 litre and when you kick on the a/c it draws the idle down enough to create a know in the engine area. Have looked at compressor, cat converter, have finally determined it is either in the trans or engine. Speed up the engine and it goes away completely. Almost sounds like a diesel. Any advice would be appreciated. Thanks.
StandOnCliff
06-07-2008, 12:49 PM
Sounds to me like your not getting enough oil pressure. This could mean either the pump is going bad,the pickup tube is clogged or the worse news,failing bearings.The time to find out is now,before it gets worse.Every time it knocks it has caused more damage to itself.Dropping your oil pan will give you access to the pickup tube.The oil pump is located in the timing cover but the pressure regulator for the oil pump can be accessed after the oil pan is removed.There is a tin piece pushed in the hole on the bottom of the timing cover.Remove this piece carefully and a spring will fall out. If you stretch this spring a bit,it will make it run a bit higher oil pressure when put back together.This spring is what they beef up when you get a high volume oil pump. Or you could just order a high volume oil pump kit,but the timing cover needs removed to do it.The oil pan has to be removed to remove the timing cover also. While you have the oil pan off wiggle back and forth every connecting rod.If they wiggle you just found a bearing out.If you find a bearing out the engine needs rebuilt or replaced soon.If you have an oil pressure gauge you could hook up before doing anything. It would tell you for sure it is running low oil pressure.The problem with a what they call an "idiot light" is it doesn't come on or flicker until your only running two pounds of oil pressure,which is more then low enough to cause damage. A screwdriver handle to your ear and the tip probing areas is a way to narrow down exactly where the knock is coming from.I would locate it before doing any of my suggestions.If it sounds like it's coming out of the oil pan then continue with any advice.
hcmq
06-08-2008, 06:21 PM
wow settle down a bit! Lets back up and get some more info first.
what year is it? how many miles? serviced properly and timely?
does the a/c work? does it make this noise any other time?
do you check your oil on a regular basis? these 3.8's like to burn oil.
once we know some of this stuff we will have a better handle on what is going on.
