does the knock sensor have to be replaced when you blow a head gasket?

 

not unless it's bad.

 

how do i know if its bad

 

Usually, it's the pigtail wire from the wiring harness to the KS that goes bad (well, ALWAYS). The KS itself seldom is bad.

 

What engine??

If 3vze, replace the pigtail.

 

I used a hammer, vise, and multimeter to check for mine. Not super accurate as it won't tell you if its the same pitch as an engine knock. But I felt better after hitting something with the hammer all scientific like

 

If your going to be in there any way....its best to replace it. Trust me.... been there done that.

 

where in hell do you find the pigtail at? napa doesnt have it

 

Where is the pigtail, might be a stupid question.

 

wtf is a knock sensor???????? llmao

 

the pigtail exits thru a notch in the drivers side head, just below the throttle body. To change it, u have to pull the throttle body, then the upper plenum, then the intake manifold, the ks will be right under the mani in the valley. If u are going to change the pigtail... I would change the sensor itself. Not much sense in replacing just the pigtail to find out the sensor needed replaced too after u get it all back together..

 

The part number for the pigtail is 82219-89103 and it's called "wire, sensor". Retails for $13 at the dealer. Definitely replace the wire as it gets really hot, causing it to get brittle over time and eventually shorts out on the head. Knock sensors are around $200 and very seldom fail. Your money of course, but I have replaced several pigtails and never a sensor. Fixed the problem each time.