Super Technical Knock Sensor Quest

Daryl Z71 · January 9, 2017

Have you seen any engines with knock sensor's rusting out or with water damage doing it the manufacturers way?

Sure have. The used motor I put in my truck with 75k miles had both holes filled with water and a corroded knock sensor.

davester · January 9, 2017

But that looks like the "original" no RTV job, not the 3/4 circle of RTV that GM is now recommending...

Daryl Z71 · January 9, 2017

But that looks like the "original" no RTV job, not the 3/4 circle of RTV that GM is now recommending...

Couldn't tell you for sure, I didn't really examine it that much when I replaced them. Definitely no water getting in now, and no sign of trouble due to completely sealing the hole.

Tom G · March 13, 2017

You sealed it all the way leaving no space? And there have not been any issues that way?

SILVER SLED · March 13, 2017

Get a temp gun and aim it in the valley and see what the temp is.

Buckwheat · March 13, 2017

Hi FWIW, I re-did my knock sensors. The ones I took out were throwing a code but actually didnt looks too bad, they had some white oxidation and the holes they went in just took a slight wiping out. They were not sealed in any way with RTV before I did this.

When I replaced them I was thinking along the lines of heat and used the Red rtv temp stuff. I coated around the outside diameter of the rubber plugs ( about halfway up...along the curved radius which would force rtv in the side walls). I then sealed the wire into the plug on each and around the outside of the plugs too.

While I was in there I replaced the intake manifold gaskets, and took that stupid foam piece out from the rear of the intake manifold...I left the front one in place. I used all ac-delco stuff after hearing the stories of folks having to back in there after using aftermarket stuff.

I havent had a problem since.

Personally I would be leary of coating the knock sensors with anything because they do work from the concept of sensing vibrations...if you should dampen that vibration with some kind of coating, you might find yourself going right back in there.

All the best!

Buckwheat