External Transmission cooler?

[V8 00USH]

Originally Posted by bcredliner

I don't recall the following being challenged: https://xoutpost.com/bmw-sav-forums/...s-summary.html.

Which part are we looking at not being challenged - there's 19 pages?

Originally Posted by bcredliner

Transmissions and engines are designed to run most efficiently at a specific operating temperature. The same is true of the life of components.

I'll rephrase that for you..."Transmissions and engines are designed to run most efficiently at a specific operating temperature RANGE"

More specifically it's the lubricants that are designed to run at a specific temperature range which then dictate the temperature of the components. Take engine oil for example. It has a very wide operating range however it's always going to work better and last longer at say 85 degrees C than it is at at 130 degrees C - even though 130 degrees is still within 'spec' for alot of modern oils.

Originally Posted by bcredliner

That doesn't mean it shortens the lifecycles of components or that by reducing the temp the life can be extended beyond the design specs.

Agreed it doesn't mean it does....but there's every chance that it will.

I have owned lots of BMWs over the years and I have to say out of all of them the X5 has been the worst by far for parts perishing particularly coolant pipes and of course the dreaded chain guides. It's currently done 125k which in the grand scheme of things isn't all that high for a modern engine, however whilst my girlfriends E46 330cd of the same era (about 8 months newer) has done over 190k I haven't had to replace a single coolant pipe through perishing. The engine coolant runs in the low 90s as opposed to the 108degrees the X5 usually runs. Is this a contributing factor - hard to say for sure but it would certainly make sense.

Originally Posted by bcredliner

I am saying you have no expert verification for what you are doing. You don't know you are right.

Similarly you have no expert verification either to be able to say that we are wrong. However I do have proof that nearly 30k miles ago I had transmission issues - harsh 2-1 downshifts and changing up into 3rd when towing. I fitted a transmission cooler and now I don't have any issues (touch wood).

Originally Posted by bcredliner

My advice is to close that gap between what you think you know and what you don't know as part of your decision.

This is exactly what I did, I went out and researched the optimum operating temperature range for our transmissions and found that I was at times well outside of this. I also found whilst researching that I wasn't alone in my situation and that lots of other people had found the same and had done similar and had good results. Even the later transmissions found in the 4.8is run cooler than ours do (by around 10-20degrees) and also appear to last longer, I haven't influenced this - however BMW most certainly have - perhaps they realised they made a mistake?