Is that the TDP? I have to tell you that it has nothing to do with the real world usage.
It tops out at 40 W, in worst case situations. I've never seen a review showing more than that. TDP is a limit, you should read it as <65 W.

Here's a classic movie about oil cooling, it makes it look so easy and fun!
http://www.youtube.com/watch?v=PtufuXLvOok
http://www.pugetsystems.com/submerged.php

That's the TDP and surely never reached in normal use, I think that normal use add only 1-3W to idle consumption. Maybe you can reach the TDP with 100% burning thou? After undervolting I'm getting that 17W with 100% burning, but I have not used the meter with normal voltage so I couldn't tell at the moment.

How about adding a slow fan to the chimney? (top or middle)
Wider chimney perhaps? If you can find another spare tube. Could make for an interesting comparison.

In fact, you can't. Here are xbitlabs results, using Prime95:

Thanks for ideas, but...
- If a fan would move the air, chimney would have no use. It's either chimney or fan, and in my case I wanted to get rid of the fans.
- If i used wider chimney, i'd need to cut the case too. There is a 12cm vent on top of the case, so I suppose 12cm tube is ideal in P182. More height would surely add to the cooling performance but in my room it's at max too.

Mats: Thanks for the link and info. I suppose my E8400 would use at max 29W with original clock and voltage then, and hitting the TDP (if even possible) would need serious overclocking+overvolting. The low idle readings were a suprise too, I suppose my undervolted CPU is <2W at idle then. I should edit one of my earlier posts by these facts but i'll pass...