How to remove nock sensors?

[ahmedomnnea]

Hi,

I want to flush the cooling system in my VX V6, some posts here said that you need to remove the nock sensors to completely flush the system, How can I remove them? do I need to remove the exhaust first to get to them? or is there a way to do it without removing anything?

thanks in advance.

[acarmody]

Don't remove the knock sensors, just use the old hose in the pipe method. Also remember to turn the heater on so that it can drain the fluid from there too.

[graham7773]

acarmody, when you say "the old hose in the pipe method" is this to drain, or to flush the block? If it is to flush the block, be a very good idea not to mix the coolant with water before putting it in as the block retains about 6 liters of water even if the bottom hose is dropped. just tip 6 liters of coolant in after doing flush. don't forget to clean the overflow reservoir and put a 50/50 mix of coolant in it to the full mark. hope this helps

[graham7773]

Ahmed, if you really need to remove the knock sensors, it would be good to put the car on ramps, even better to put it on a hoist. There are two knock sensors, one on each side of the block at the lower part near the engine mounts. each one has a metal shield over it. unbolt the shields, remove the knock sensor wires/plug (they oval, just squeeze the oval and pull gently) and unscrew the units (22mm socket, universal swivel and extension). when you refit them, some thread seal (loctite 242) on their threads will prevent leaks and stop them coming loose , tighten to 22nm. Don't over tighten as you will be buying new knock sensors. Shield bolts go up to 35nm. all the best.

[ahmedomnnea]

thans for the replys,

first, whats the "old hose in the pipe method"?
second, whats the nut size of the nock sensor?

thanks again.

[graham7773]

I am not too sure of "the old hose in the pipe" method. I think it means just flush the motor and heater core by putting a garden/water hose in the top radiator hose and dropping the bottom hose so water runs through the motor and heater core do the same for the radiator. This only works if you remove your thermostat first and turn your heater control to the hot position. I gave you the size of the knock sensor nut/socket in my last post, it is 22mm

[acarmody]

Thanks for answering graham7773, yep thats what I mean. If you do this right then it will get most of the coolant out. You will never get 100% of the coolant out no matter what you do.