Citroen XM Forum

indeed it is, keeping the gear oil at the correct temperature is critical for gearbox life.

Anyway, had a quick half hour in the shed, go the puller out to get the sprockets off the shaft, pressed both bearings out, measured them at 7mmx22mmx7mm and ordered both new ones, Mr bearing can do them for the staggering price of £1.47 each, seems daft to use the old ones at that price and pressing them out is easy with a massive box of old sockets and a stonking big vice, happy boy again.
photo(88) by Deanxm, on Flickr

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Actually, not Mr bearing, but http://www.bearingboys.co.uk/Chain-Sprockets-1037-c" onclick="window.open(this.href);return false; could supply all new sprokets as well as bearings and other things that make my little eyes light up!
went for the much more expensive SKF brand bearings instead of budget, £6 for two, now off to continue browsing the store....

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There's also the UK stockist Just Bearings, if you need another one.

While reading your thread, I did peek at the transmission oil cooler on Citroen parts. I know the diagrams are a bit generic and don't necessarily show the real thing, but the V6 box cooler did look rather like the Valeo aluminium heat oil-water exchanger fitted to the 2.5, albeit with pipework at different angles. If it is from the same stable, I can understand why anyone would want to get rid of it!

Agree that an effective fluid cooler is essential. Oil-to-water has the advantage that the cooling water is always there, which an up-front air-to-oil cooler doesn't enjoy, and when you might need it most: in crawling traffic with not a lot of forward airflow.

The fluid cooler will stay on the gearbox, the engine oil cooler will not, i just dont hit the standing traffic in high temps and the engine doesnt produce the power to warrant it, i may add an air cooler later, i take your point about standing traffic but if you need an engine oil cooler i dont see the point in loading up the coolant system with the heat.

Just to be clear for future reference, the ballancer shaft chain drive idler sprockets are NFP from citroen and unobtainium on the open market, replacement bearings should not be required unless the engine has been stood for years in a damp environment but, if you need them, they are Deep race open ball bearing 627 J30 manufactured by SNR measuring 7mm shaft, 7mm width and 22mm OD.

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As mentioned earlier there is also the gearbox oil radiator Dean, which I suspect does more cooling work than the water cooler once the car is warmed up and in motion! Even when stationary the two-speed fans obviously provide some good airflow. I appreciate the 2.0i does not have the feature, but the V6 generates a lot more heat and there is also not much too space in the engine bay!! With regards, Matthew T.

MTXM wrote:As mentioned earlier there is also the gearbox oil radiator Dean, which I suspect does more cooling work than the water cooler once the car is warmed up and in motion! Even when stationary the two-speed fans obviously provide some good airflow. I appreciate the 2.0i does not have the feature, but the V6 generates a lot more heat and there is also not much too space in the engine bay!! With regards, Matthew T.

Think about it this way.
A v6 12v can generate 130kwh of motive power. At best is will be about 25% efficeint, so at best it is creating in the region of 390Kwh of heat output. That's a lot of heat to dissipate.

ah but most of that heat will be ejected in the exhaust gas itself, there will be higher heat output from the headers than a diesel but the engine block itself will be the same temps as a diesel, i will be very surprised if the actual block temps of a petrol are much higher than an oiler.
My manifolds will be insulated, the runners are factory insulated, there is no turbo to increase radiated area in the engine bay, i think the gearbox will be just fine with just a water cooler running on a well maintained and clean coolant system.
If in use i see excessive gear oil temps i will fit a thermostatic air oil cooler and the same for the engine oil but until that time i want to keep the engine bay as clutter free as possible, dont forget some of the heat from the radiators comes back through the engine bay anyway.

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Can anyone see an issue with rinsing a torque converter with diesel? Sounds odd but I would think diesel wouldn't harm anything in there and I want to get it really clean as its a big trapping point for old oil and gunk, the box has been sitting a long time and all the dirt settled out of the oil, it came back into suspension in the oil quickly but I don't want to start on a Back foot with dirt in the box, it took dozens of changes to get the 8v gear oil to stay red.

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2 issues occur to me:

1. Any residual diesel in the torque converter and transmission will play havoc with the properties of the transmission fluid, and will take lots of flushes to get rid of.

2. It is standard practice to flush the torque converter with inert fluid (or a fluid with very high flash point) to eliminate the possibility of explosion of the torque converter. I would think that diesel is marginal in this regard.

I wouln't introduce diesel into the TC either, for the reasons above. Maybe there is professional advice on TC cleaning on the web.
Would have thought a non-damaging and non-residual solvent (like IPA/industrial alcohol?) might be ok. Fill and sloosh about repeatedly, and them blow out dry with an airline. Just a guess.

You're right to give g/box cooling priority over engine oil cooling. The disadvantage of air-radiators for this purpose is that they aren't too good at shifting heat away from the box when the car isn't moving forward. Agree that all transmission-to-water coolers do is shift the heat into the cooling system, but the important point is that they shift it away from the transmission (and do it pretty efficiently) - the cooling system can look after itself, with its twin fans on tap.