Long story but last summer I had the big lower coolant hose blow off at the thermo housing. It sprayed coolant all over the engine and immediately shut down. Replaced plastic thermo tower, upper and lower hoses, crossover pipe and short hose to thermo tower but not thermostat since it had been replaced recently with a coolant flush. Did do the water-in-a-pan-on-the-stove test and it seemed to function as expected.

After all the coolant everywhere had the knock sensor code for a day but after it dried out codes went away.

Now I have developed a slight 'rattle' from the engine under very light load only at about 50mph. Three thoughts, 73k mile cats rattling, exhaust system rattling, or light engine knock. Ninety-three octane gas. Sounds speciously like knock sensors shutting down the spark advance but I do not see any evidence on either TORQUE displayed spark advance or knock sensor signal.

Any similar experiences or opinions out there?

Any failed knock sensors without associated codes?

 

You have to replace the knock sensors(microphone has internal damage),

remove all 8 coil packs, remove all 8 spark plugs,clean the coolant out of the spark plug valleys using a dry paper towel,

remove all 8 spark plug coil boots clean the springs and inside and out with electrical contact cleaner spray, replace all 8 plugs with new plugs of the same type.

change your oil and filter as well.

my xk8 did the same thing when I had it, it was a learning experience

 

Sorta suspected the knock sensors but wanted to hear from other experiences.

Thanks!

 

On-line pricing ranges from $25 for Airtex to $130 for OEM. Any experience with the low priced spread?

 

Tom,

I got my Knock Sensor from Jagbits.com

I also had problems with my knock sensors being in contact with water but mine set a code.

I wish you luck

 

cheap ones work better than OEM yea I said it BETTER THAN OEM

 

Guess that settles it for me. $21.79 at RockAuto with a one year warranty, two years if I put it on my Visa card. Labor around here is cheap. Had the intake manifold off the V8 Volvo twice this week for a coolant leak.

Tight Wad Tom