Hello. I'm new to this website, and I've recently purchased a 1994 Suburban with a 6.5. I have a knocking noise that is coming from the rear of the motor on the passenger side, underneath the turbo. When the motor gets up to temp, and is running down the freeway, the noise goes away. What could be causing this?

Thanks.

 

check the frt drive pulley on the crank-they come unbonded over time and cause a lot of problems.
powerbond makes a replacement you can get from Orielys or your local motorstate vendor.

Remove the drive belt and if you can rock the pully with your hand it's junk-you can also just look at it to see if there are shiney spots where the mounting bolts have been hitting the webbing.

 

can this maybe a sticky injector?

 

Always a chance?
Any unusual smoke or a miss?

 

nope when it gets up to temp it runs like a champ i have a 97 6.5td in a pu and this is new to me

 

Could also be a problem with the temp sensor in the coolant crossover manifold?
If it is giving a bad reading to the ECM timing is affected.

 

when i got the thing the temp gauge didnt work so i put in new temp sensors one on the manifold and one on the driver side of the block. could one of these sensors b what your refering to?

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oh no shiny spots on the bolts holding the crank pulley on if i understood what u said

 

The sensor in the water crossover is for the ECM only,the sensor in the cylinder head is for the gauge only.

AC Delco is the only functional replacement electronics for these trucks-aftermarket parts are under engineered and often bad right out of the box.

The shiny spots you need to look for are on the webbng moreso than the bolts,the best test is to lossen the belt and remove it from the drive pulley-then try and turn the pully by hand and if it moves it's junk.