2005 4.8 in a silverado. he has replaced knock sensors 3 times! doing new intake manifold gaskets each time lol. first time threw code. took intake off and knock sensors full of water. put new ones in. 2 weeks later same thing again. this time he put silcone i believe around them to keep water out. happened again.replaced one more time.. parts sotre thought he was lieing because snesors were only couple weeks old and looked old and nasty.

i told him i would ask on here. he says everytime they filled with normal water.. no coolant oil or anything. just water.

Any ideas?

 

How often is he washing the engine? Does this happen after a rain?

 

i was curious about that also. we have come to the conculision it has to be from rain or some sort of water. i havent even looked at his truck yet. i wanna check if the rubber seal is on the cowl still where hood meets firewall.

he told me this lastime it happen he was driving down the highway and it just clicked on. he told me it losses a ton of power once light was on.. i couldnt help but laugh thinking of a stock 4.8 with even less

 

When I had to change mine, the back one had a little rust on it. I'd say pull out the water hose & soak it down & then pop the hood.

 

yeah ill talk to him more. he said its always dry under the intake but inside its wet

 

Thats a Captain Hindsight statement if I've ever heard one!

I've never heard of this problem. Could it be condensation? I know Florida gets a little humid sometimes. Try putting talcum power on the valley cover next time the intake is off so you can see a trail of water the next time it happens.

 

LMAO, glad you caught it

 

Has he replaced the knock sensor wireing harness? That harness could be rusted. I replaced mine (only sensors) and had the light come back on about 6 months later.

 

This happend to me i took the cowl off and sold it and havent had any problems sence

 

when mine went out, I replaced the sensors and wiring. I also took off the foam so that it could breathe. I akso added some silicone around each one. Didn't have any problems for 50k aftr that.