I went to pull the knock sensor to drain/flush the block and it appears to have broken off in the block. Looks like I'll have to try an ez-out and if that doesn't work, drill and retap. Anyone know what size thread it is?

 

Sorry, false alarm. Once I compared the old sensor to a new one, it was obvious that it hadn't broke off. The hole in the block was sealed with scale and junk and the old sensor was pretty eroded on the end. When I pulled it, I was expecting water to be coming out and when it didn't, I freaked.

 

Yeah, I've seen that once before, went to drain the block in a buddies jeep (350 sbc), pulled the coolant drain plug out (where the knock sensor is on our cars) and nothing.. Have to say that it took me by surprise.. Took a little screw driver and a little tap-tap later, I had coolant gushing out like it was supposed to.. Had a layer of solid crud that completely sealed the area behind the plug..

 

would someone be able to describe where the knock sensor is? When i go to flush my coolant i want to take that out to drain averythign too. Im assuming at one of the lowest points but I want to make sure what it looks like.

thanks

 

The knock sensor is located on the lower passenger side of the engine block near the starter. It's located just above the oil pan in the engine block. It's round and has a white connector on it. The car will have to be up in the air to see it. Hope this helps.

 

yea thanks, i can picture the area your describing, shouldnt be a problem.

i appreciate it.

 

the knock sensor in the 300 and 350's are almost always a 1/4in NPT which means the hole is little smaller than 1/2 inch... i dont know the exact mesurement.