Citroen C6 transmission whine resolution

[johnwh]

Hi, it’s been a while sorting out a problem with a transmission whine in my 2006 C6 2.7 . There was also a vibration at idle which was largely removed by replacing the left engine mount but the whine remained. Finally I also changed the main transmission mount and the whine has gone and the idle vibration completely resolved except for a terrible noise when it’s put in reverse. I believe this is because the engine is now rocking forward or back high lighting how shot the other 2 mounts are. I am now going to change the remaining 2 mounts. The front engine one will require the radiator being removed so at the same time I am going to replace the plastic coolant intake pipe to the engine.
I think in general parts for these cars are becoming more difficult to access and Citroen are dropping listings all the time. I managed to get a rear mount from Lithuania but not cheap. It will end up costing close to $700. I bought a new front one a few years back and would hate to know what Citroen Australia would charge For these items now.
Anyway, I just thought I would mention how important all those mounts are and it would probably be wise to replace them soon as they are going to get more expensive and or difficult to acquire. In addition, I am in the process of replacing as much of the plastic components, especially coolant ones, as I can.
Having just replaced all the spheres I am still getting an occasional suspension warning which my tool says is an open circuit or lack of ground on the right side suspension unit. Not sure yet how to deal with that as it appears ok but will see.
This is a demanding car but for some bloody reason I stay committed to seeing it through even,with my limited knowledge and skills.

 

[johnwh]

I forgot to mention above that I am about to replace the thermostat and while the radiator is out doing the front engine mount I am going to have a level sensor fitted that will be wired to a light and beeper in the cabin . Redarc make what appears to be a good sensor and they strongly suggest placing the sensor in the radiator as opposed to expansion tank. I don’t want to cook the motor by a sudden loss of fluid and apparently the reason Citroen removed the level sensor from the expansion tank was that it set up a capillary action that transmitted fluid back to the ECU and fried it.
Cheers John

 

[gwest]

I always thought that a coolant level sensor in the expansion tank was a wonderful thing because not only would it signal gradual coolant loss but also sudden loss in a catastrophic incident. However, it was pointed out to me that in some catastrophic situations the level in the expansion tank might not go down until it was all over. They recommended a sensor in the top radiator hose, and provided an insert that simply required cutting of the hose. I think this is less likely to cause problems than penetrating the radiator tank.
And I share your fear of capillary action- I lie awake at night wondering what fluids are sneaking up the wires of my ageing collection.

 

[johnwh]

Cheers. I smiled reading your difficulty with sleep worrying about sneaking capillaries.
I have seen those in line sensors and if I end up not being confident about the radiator route I will head that way. They are also cheaper which is a bonus.