Thursday, April 3, 2014

What is that noise...

tick tick tick.. rattle rattle rattle... buzzzzz...knock knock...clunk
wtf is that sound!?!?

From a cold start I was getting more then normal valve lifter noise and also some exhaust noise. Under acceleration the motor would go quiet but after letting off the throttle it would go noisy. When warm it sounded like a bunch of ball bearings in a blender.

I put the van up on the lift at work and found that the exhaust pipe had cracked through at the flange at the cat. I welded it back together and that quieted up the exhaust noise but I still has the other more serious sounds to contend with.
Then I noticed that I was about half a quart low on oil and also realized that I was still on the winter= oil 10w30. Once I topped it up some of the lifter noise went away, but the other more sinister noises were still there.

So I decided to do an oil change to 20w50 still thinking that it was a noisy lifter. I pulled both valve covers off to see if I could find anything wrong with the rockers. Didn't see anything there either. The motor did quiet down with the fresh oil but it was still making a knock sound.

Oh God I thought, I am losing this motor.

After driving it back home I started poking at various parts to see if anything had loosened up. While turning the crank by hand I could feel metal on metal contact. I was able to narrow down the location of the noise to somewhere inside the torque converter area. I pulled the rubber plug covering the access hole to the flex plat bolts and found two of the three bolts had loosened up and were letting the flex plate slap around.  Unfortunately one of the tabs had cracked but I was able to re-torque the bolts and the terrible noise went away. So now I have to split the trans case and replace the flex plate. When I do, I will flush the differential and the transmission and do the CV boots. I've already purchased a used flex plate from a local shop and the rest of the parts are on their way.