Christi@n

Hello next days, i will plan to complety flush and refilling cooling system,
Removing knock sensor, is better to place a brand new couple of them?

Or can I re fit with these?

1984Z51auto

If the sensor is OK, there is nothing to be gained in replacing it when you drain the coolant. They are really just microphones for the knock sensor and appear to be pretty sturdy.

Christi@n

How i can determine if they are ok?

antfarmer2

I just did mine I just can't bring myself to put back in 20+ year old parts pull the shrould off and clean between them

WW7

Whatever you decide to do , just make sure you torque the sensors to spec when you put them in ,or they won't work properly...WW

don hall

Replace with new sensors, and pay attention to the torque specs.

Cliff Harris

The ECM tests the knock sensors every time you start the engine. It will set an error code 43 if the knock sensor or ESC module is bad.

davewhtt

DGXR

I figured the computer did some kind of test on this part of the ignition system. Also, a bad knock sensor would cause all kinds of drivability issues, wouldn't it? Do they go completely bad all at once, or do they gradually lose sensitivity?

I just did a full cooling system flush & fill -- the knock sensors did not require any mangling to remove from the block, they were shiny clean and appeared in excellent condition, so I reinstalled them. There are no codes, no starting or drivability issues, it has loads of power and runs fantastic. There's $70 I didn't need to spend

Research shows the installation torque for the knock sensors is 14 ft-lb. This is important. I used a wee tiny dab of anti seize on the threads. I didn't use any thread sealer because I understand the knock sensors need a ground contact on the block.

Christi@n

This is a reliable information

Christi@n

There are a lot of different opinions about this,

Would ask to who had say to replace them,
Why is prefereable to replace them?

c4cruiser

If the ECM is not reporting a Code 43, then the knock sensor(s) are working. If there is going to be a problem with them, it would be if they are damaged when they are removed from the block.

Most owners (and shops) do not remove the sensors when doing a cooling system service. Over a long period of time, the bottom of the coolant passages of the engine block can load up with sludge and when the knock sensors are removed, nothing comes out. A pointed rod or piece of wire has to be shoved into the hole to dislodge the gunk so that coolant can drain out.

It's important to make sure that the threads on the sensor and in the block are clean when the sensor is threaded back in. A small of anti-seize lubricant should be spread on the threads, then the sensor can be re-installed.

davewhtt

I t was suggested by some on this forum that in order to do a complete flush i should remove sensors. I found ac delcos for around 23$. When i saw what came out of the block i was glad i had the new pair to go in. What c4cruiser said is spot on. Yes you can re use alot of car parts and i do when i have to. Dave

1984Z51auto

I know I'm late with this but, no error code = no issue with the sensors.

desertmike1

The only valid argument about replacing a good sensor, is the fact that "If" you damage it internally while removing it & reinstallation, and it comes up faulty later on.. Then you will be draining over two gallons of Antifreeze all over again!!

Having said this; I did not replace mine, and have not had any issues..

Now you decide..

antfarmer2

Not true other factors do come in play need to use the right compound to make sure it grounds right it is a 20 year old part and will go in a bit further the second time to get the right torque messing up the distance it goes in and does my fat old *** want to get under the car again

scooter mcfly

Better to have it and not need it than to need it and not have it. I like to have spare parts in the garage. Especially the ones that don't cost a lot, like knock sensors. So go pick one up. Or two if your car needs two. If you ever break one, you'll have a replacement on hand.

Christi@n

Christi@n

Well think I will take Two new ks, just to be sure in case of their fracture

Christi@n

Where do you buy ac delco ks for about 23$, ROCKAUTO?