hi all i just got a 99 318 1500 2wd. so far i have fixed the usual problems. fixed the plenum with A Hughes plate, removed crud and sludge from oil gally and rocker arms, and even dropped oil pan to clean that mess and put in a new screen and pump. so the truck runs good save a funny sucking/vacuum noise at 1/2 throttle. in any gear if you go 1/4 no noise, 3/4 to full no noise. i changed the belt still noise. any guesses? i'm stumed. and annoyed

 

was the noise there before you changed plenum?
do you have a throttle body spacer?
how about the throttle body gasket? is that in good shape?
check your vacuum hoses for disonnected or possible damage.

 

Yes
No
never took the TB off of the intake
Triple checked for disconnects.

i even took a buddy for a ride and asked him what he thought it was. first he said vacuum leak then said belt whine. we sprayed the new belt with some belt dresser. no change. what about fan clutch? or leaking between big airfilter box and TB is there a gasket for that? mine only has a "hose clamp"

 

do you have a aftermarket air filter? not saying a cold air intake but even just a k&n drop in filter. is your intake tube seal TIGHT around the throttle body along with the gasket between the top of the tb and the intake tube?

 

nope i have a purolator replacment. the tube is as tight as i can get with a screwdriver. i don't have a gasket between tb and tube. see pics.
http://img.photobucket.com/albums/v7...9/IMG_0397.jpg
http://img.photobucket.com/albums/v7...9/IMG_0399.jpg
http://img.photobucket.com/albums/v7...9/IMG_0398.jpg
http://img.photobucket.com/albums/v7...9/IMG_0400.jpg

 

You definetly SHOULD/MUST have a gasket between your T/B and aircleaner or it will leak and make that sound. Plus, you're rendering your filter useless because all the stuff you are trying to keep out is going in there!
Air cleaner gaskets are the forgotten gasket on a lot of rigs...

 

i thought it was strange it didn't have one.
http://www.partsamerica.com/ProductD...pe=518&ptset=A
for 1.68 i'll get like 5 and have spares.

i'll let you all know tomorrow.

 

mine didnt come with one either. looks like its got a pretty good fit but could probably use a gasket anyway.

 

That was the problem! put it on and all is well. Thank you

 

Holy Crap!

I've had my truck for over two years and never knew there was supposed to be a gasket between the TB and filter! I have had that noise while the truck is warming up since the day I bought it. I had just thought it was "one of those perks" of owning my Dodge. I'll definately be stopping at the local NAPA store on the way home tonight!

Learning things like this is what makes this website a definate plus!!!! [sm=hail.gif]