99 dakota noise

From : me

Q: i have a 99 dakota 3.9l engine with ac. recently it began to make aloud engine noise. when i dropped the serpentine belt the engine was quiet. i replaced the belt tensioner as the indicator mark and arrow were aligned and my haynes book said that means it needs replacement. i also put on a new belt. the noise was significantly reduced. then using a rubber hose as a stethoscope i could tell that the idler pulley was making noise. a little wd-40 quieted it down so i replaced it assuming the bearings were shot. but still there is a lot of clacking and racket noise. in the old days i could test each component by dropping its belt but with the fan blades so close i dont know what to do next. also i couldnt find a torque spec for the idler pulley bolt and wonder if it is sensitive to torque i just snugged it up good. ive been out of work and dont want to spend money on a mechanic so any help would be appreciated. thanks. .

Replies:

From : tom lawrence

shot. but still there is a lot of clacking and racket noise. are you sure the fan isnt coming into contact with anything .

From : tom lawrencetom lawrence

i just found out that my transfer case will not shift into 4 wheel drive. of course i find this out when the storm hits and i have to run out and go to work i live in massachusetts okay - lets first determine if its a transfer case problem or a cad problem. put the truck up on jackstands put it in 4wd and verify that both front and rear driveshafts are turning. alternatively wrap a long zip tie around the front driveshaft so that it will smack the floorboard when it turns. drive the truck in 4wd and listen for the ticking sound. if the front driveshaft isnt turning youve got a problem inside the transfer case. thats about as far as you can go with it. if the front driveshaft is turning then youve got a problem with the center axle disconnect cad mechanism in the front axle. first a quick explanation of how the whole system works the passenger-side front axle shaft is actually in two pieces splined at the inside joints and coupled together with a locking collar. the cad uses a vacuum-actuated shift motor to move this collar back and forth to either engage or disengage the axles. when the axles are coupled together youre in 4wd. when the axles arent coupled together youre in 2wd. when not coupled even turning the front driveshaft wont do much of anything - just spin the differential gears but not the tires. now the cad motor is controlled by engine vacuum. theres a vacuum switch on top of the transfer case and two vacuum lines run from this switch to the cad motor. vacuum is applied to either one port or the other of the shifter motor to move it in either direction. when you shift the transfer case into 4wd vacuum is applied to the opposite side of the shift motor moving a diaphragm inside which moves the shift fork which slides the collar into place over both axles locking them together. now - on the cad opposite the shift motor round-looking thing about 3 in diameter about 1 wide is the 4wd indicator switch. this is what lights up the dash light to indicate 4wd. it is a normally-closed switch held open by the shift motor when in 2wd. the fact that your light isnt coming on when you shift into 4wd makes me strongly suspect that the cad isnt operating either from a lack of vacuum or some other problem. to check for vacuum remove both vacuum lines from the cad note the orientation so you can put them back the same way. plug one line and with the engine running feel for vacuum on the other line. if you dont feel anything switch lines plug the open one and check for vacuum on the other. then shift the transfer case into 4wd and re-check vacuum. if you only havee vacuum one one line suspect a broken line between the transfer case and the cad. if you have vacuum on neither line suspect a broken line between the intake manifold and the transfer case. if you have vacuum alternating on both lines when you go from 2wd to 4wd then the problem is somewhere in the cad itself. if the cad itself is at fault hook the vacuum lines back up remove the cad from the axle 4 bolts - some gear oil will leak out so have something to catch it in and have someone shift the t-case from 2 to 4wd with engine running while you observe the cad. if it doesnt move at all the diaphragm inside the motor probably failed and youll need another one. if it does move properly check the collar inside the axle to make sure its not binding up splines are twisted or something like that. that oughta be enough to get started with .

From : whileetimberwolf

replaced distributor cap rotor plugs idle air motor and battery and it still stalls. it idles around 300 rpm. any thoughts thanks .

From : timberwolf

is it a clanky rattling noise if so the timing cover is right next to the serpentine tensioner. your timing chain also has a tensionerand these have been known to go bad on the 3.9. could be your timing chain rattling. .

From : me

thanks for your help. the next day the water pump suffered a large failure-- all at once. no weeping or indications other than the noise and then pop and coolant was flowing out as if the hose had ruptured. .