I noticed that my 2002 S40 started to make some what of grinding noise on a cold start everymorning and once it heats up it goes away, at the same time the "check engine light" appeared. I took it to a friend and had it checked, Code PO128 appeared. I googled it in this forum and found out what it meant. Could this noise be corrolated with a faultly coolant thermal sensor or thermostat?

Help would be greatly appreciated!

 

This noise typically wouldnt relate to the fault in your tstat sensor, however I have heard of bad tstats making noises. I would replace the sensor and tstat and then see where you are at...the noise could be something totally different. I currently am driving with that code and don't have any weird noises, not saying its not possible, just unlikely...

 

Thanks for the response, I am going to change does two parts this weekend and hope that the noise will go away. I did notice that after a few minutes the noise goes away, and it doesn't effect the performance.

 

Again, codes shouldn't be associated with the noise. I have 84k on mine and just recently replaced the sensor and thermostat, seems to be a common thing. Only time I head a grinding noise upon start was when we hit -10's and colder here in Wisconsin. But at the same time my wife's Honda Element did the same thing. But just like you it went away once it ran for a few minutes. I wouldn't be too ill concerned, just replace those two parts, IMPDUSA.com sells both with shipping under $50.

 

you say grinding noise, does it run in a cycle motion and then when it heats up is there a slight knock like noise like a clock noise coming from it instead like an intermitten sound as if something is trying to cut in?

 

Not really, it's more of a rattling and it comes from where the turbo area is. I did notice that's more noticeable as the car is taking off or as I accelerate, but the noise goes away after a few minutes of a cold start. I was able to get rid of the PO128 Code. But the noise is still there.

 

I can find the tstat ( btw which is the correct one ? 87c or 92C ??) but I cannot find the tstat sensor... Would you mind pasting the URLS where you did bought them please ?

Best Regards.