Radiator location.. In or Out?

I am building a very modded water cooled system and I can pretty much put the parts where I want them.

I was trying to decide on location for radiator (5X7) and was about to mount it at the top in the standard blow hole fashion when I started thinking.

If I blew air out over the radiator then I was essentually cooling it with the case temp air. ~35 degrees so there would be no way to get the radiator cooler than this (Maybe my assumption is wrong)

If I reversed the fan and sucked in then I would be getting cooler outside air going over the radiator but then Id be adding to the heat of my case by warming the incoming air with the water temp from the CPU/GPU.

Ideally I thought would be to hit the radiator with cool external case air and then exhaust it out of the case. Indeed Ive seen this done.. but it takes alot of case space and Im not using a full tower.

Currently I have my radiator mounted right on top of the case. Fresh air in, hot air out.. I think it looks kinda cool..

Are we sacrificing case temps and water temps for aesthetics if we mount the radiator inside the case?

I have seen the front intake scoop, over the radiator and out the bottom mod and thats nice, but again.. it takes alot of space.

Personally, I would never mount a radiator at the top of the case. Hot air rises to the top, and your radiator would be cooler, blowing onto the radiator on the floor or somewhere out of the case. You should experiment, but whatever your fans are doing, it's either going to be blowing out hot air from the case, or sucking air from the radiator (I've never seen anyone do that, so it shouldn't be a good thing).

Yodums

The best thing would be to have it seperated from the case airflow, but space is precious, especially in a midi tower.
I'm gonna have it at the bottom front, cooled by air from the outside. Sacrificing a couple degrees case temperature for cooler water temperatures.
The CPU is what benefits the most from cooler temperatures anyway.

think outside the case (sorry couldnt resist)

By placing the radiator outside the case (whereever) you get cool air in, and GUARUNTEED exhaust of the heated air. I am a big form over function guy so I think im going to sacrifice aesthetically pleasing interior radiator design for better cooling, better exhausting external radiator. I think alot of time we do things just because "thats the way everyone else does it"

Ideally, Id like a completely ISOLATED internal radiator with intake and exhaust vents. I would do this if I was going with full tower..

If your computer isn't mobile, i.e. you don't take it to LAN parties, then place everything outside the case, except the Water block of course. Now you can deal with the CPU's extracted heat outside of the case. Also, you now only have two hose connections inside the case, so less chance of a leak doing damage to the electronics. The less plumbing inside my case, the better I like it!

When I was using my home made water block, everything was copper, and soldered. Instead of hose barbs, I had 3/8" O.D. copper tubing coming out of the block, bent into a 90 degree angle, then exiting the back of the computer, right above the Keyboard and mouse OS/2 connectors. The copper tubing extended about 1 inch outside the case. SO, I had zero hose connections inside the case. I made a 1/4 inch plywood box to house the pump, radiator, fans, and resevoir. When I mounted everything in the box, I tried to keep everything the same height as the water block, to minimize head loss. The box sat right behind the computer, and I think I ended up using less than 3 feet of hose. When you build the box, you can build the radiator shrouds right into the box. When I opened the side of the comuter case, I had as much access to stuff inside as when I used a HS/F.

The only thing is, if you do this, the computer & box should be in an out of the way location, so the case and box aren't bumped or jarred. You don't want one or the other moving around and putting stress on the tubing between them. In my case, (no pun intended) that wasn't a problem.

Pudge

radiator

I'm gonna mount my radiator on the outside of my case next to my external fishtank reservoir, and probably behind my pc. I use a small 8 inch room fan to cool it. Once I buy a radiator and waterblock and finish the H2O setup that is... provided I don't decide to waterproof and use a minifridge...

As for LAN parties, they're hosted at my house

I only have limited experience with water cooling so please consider others opinions. I am using a Black Ice Prime mounted in the lower front of my case. A 120mm fan draws air in and over the radiator. It is then exhausted out of the case by the power supply and rear 80mm exhaust fan. The capacity of the cooling system exceeds the heat input from the CPU (1.8Gig Northwood at 2.1 Gig) by such a great margin that there is no readily noticeable temperature rise across the radiator. I am sure there must be one but it is certainly not easily noticeable. In other words, it does not appear to me that there will be any easily measurable increase in case temps by drawing air into the case through the radiator.

I have my radiator on top if my case as am using a mid tower as well. I have the fan under the radiator blowing out the top.

Now what I found I had to do to get my temps down that very close what I would see outside the case is to add extra fans to the case. You need to have very good air flow though the case

This works well at one point I moved the radiator to out side I saw 1 C drop and I can live with a 1C higher cpu temp for the mobil case

It can work and work well you just a higher level of air flow though the case.