Finding and Using Radiators, Part I

From: Andre

Here is a cheap and easy to obtain ideal for a radiator for water

Often, large cars and trucks will have a small power steering or
brakes system that requiring cooling.

To do this they use a small radiator about 8″ tall, 4″ inches wide and 1 or 2″ deep with around a 3/8s inside
diameter. They should be big enough to attached a pair of 92mm fans to. The fans will have to be wire
tied on as there is know way to screw them on. The last time I had to buy one it was about $30.

From Ralph ‘Gravedigger’ Burket

I am head maintenance and mechanic for the cemetery here and have worked on a
lot of vehicles.

I use a cooler from an auto in my system. It works great.

One problem I found with his idea is that brake systems and power steering
systems do not need or use cooling. The pressure in the brake system is too
high for any kind of aluminum cooler (they use steel brake lines). I think
the coolers he is thinking about are aftermarket oil coolers, or, my
favorite, transmission fluid coolers.

You can go to a salvage yard and pull a tranny cooler off any minivan (most minivans come factory with tranny fluid
coolers, most other vehicles it is available as an option along with the tow
package). If you are good with the owner he will usually just give the
cooler to you if you pull it yourself.

Also, flow rate is no problem because it uses 3/8″ nipples then the rad. pipe expands to about 1″ diameter. So
when the coolant gets to the rad. it slows down. Now this is on the tranny
cooler I got, not all of them may be like this.

Also, if you really want some hardcore cooling and need a BIG radiator, look
for a auto with both the motor and A/C pulled. With the motor pulled, the
refridgerant is usually drained from the A/C system and you can take the
condenser. It is a thinnish looking radiator usually mounted in front of the
auto’s main cooling radiator. This thing was made for supercooling! Hope
this helps.

My System:

Generic mid-tower

250w PS


192M generic PC100


Celeron slot 1 366 O/Cd to 500 with a home rolled drilled copper waterblock,
tranny cooler for radiator, 4″ marine junction box for resevoir, and generic
submersible fountain pump

Running full load I hit 102 F at 2.2v. Need
TEC’s for 550.

From Shamus Shabazz

My waterblock uses 3/8″ tube (like most), so i just went to a auto
wreckers place near me and picked up two HUGE rads for 5 bucks.

The kicker is that I live in Canada, and $5 is less than $3 American, and the auto
wreckers has tons of these rads all over the place, ALL for $5, if
not less, dollars. (If you want, I can get pictures of them and send them to
you.) Anyway, since i am using the 3/8 tube, I just connected the two, they
are a perfect match. The performance is just as good as any other rad and the price is incredible!

From Barry E. King

I use a transmission oil cooler sold at Checker Auto parts under the
Imperial Automotive Products brand name Enon-O-Kool. The price was
approximately $25.00 USD in Phoenix, Arizona as of May/June 2000.

It is a 6
row cooler that measures 10.5″ x 5″ x 0.75″. The only feature that I can
see about it that may distinguish it from others is that the radiator tubing
contains a spiral insert which directs the fluid through the tubing in a
spiralling fashion. (I hope that makes sense.)

The inlet/outlets accept 3/8″ tubing. I used 3/8″ ID high pressure (cloth
reinforced ) rubber water hose throughout the cooling system. I use a
Little Giant submersible pump specified at 170 GPH at 6′ 4″ (it works as
advertised — I tested it).

The pump is housed in an in-ground electrical
junction box. These boxes are water tight and have a lid that screws into
the box sealed with a foam rubber seal. Two brass 3/4″ nipples (1/2″
threaded to 3/8″ barbed) are fitted into the lid.

A small hole with a
rubber grommet seals the pump’s electrical cord near the top of one of the
sides of the container. A water-tight thermal probe sits in the resevoir
below water level and that wire shares the grommeted hole with the pump’s
cord. This reservoir virtually eliminates the possibility of coolant loss
due to evaporation.

The radiator has two 4″ 120 VAC fans attached to it. These fit almost
perfectly on this particular radiator. The setup allows the water to
maintain a steady state of room temperature within a degree F or two, with
or without a 50W Peltier on the CPU. Placing the radiator near an air
conditioning vent would easily yield well below ambient water temperatures.

I suspect this radiator is overkill. Something half of its size should be
adequate for most purposes, but this one was reasonably priced and works
very well.

At the time I built this rig, I was attempting to get 900+ MHz from a ca2
SECC2 P-III 600E. The water block is fabricated from a generic Pentium III
SECC2 heatsink. I removed extraneous heatsink fins to allow a cap to fit
snugly. Version 1 used a small plastic weather-proof electrical junction
box readily available at places like Home Depot. Although it functioned
very well, this approach proved to be far too large to be practical

(NOTE: I later found this approach to be used by an online vendor. This is not a
viable solution in most cases as it consumes far too much precious case and
motherboard real estate).

Version 2 used the end of a plastic sewer cap. I cut the square plastic end out of the cap using a hacksaw and squared it off
with a rotary tool and attached it to the heatsink using JB Weld. 3/8″
brass barb fittings, one straight on top, one elbow on the front, direct the
coolant flow.

Coolant is pumped from the resevoir through the radiator to the water block
then returned to the resevoir.

This arrangement easily out performs an Alpha P3125 with room temperature
coolant. Adding a 50W Peltier was good for sub-zero temperatures. Redline
Water Wetter is good for a few degrees extra cooling efficiency with the
added benefit of eliminating aluminum corrosion. Do NOT use glycol based
coolants UNLESS you are chilling the coolant to below freezing. Radiator
anti-freeze has far less efficient heat transfer characteristics than plain
old water and will work against you.

The entire rig can be housed in a large case with some work. Smaller cases
may have to mount the radiator and possibly the resevoir outside the case.

Hose clamps are used throughout to secure the hoses in place.

The things I would like to change in the future:

1) Use an inline pump. While the Little Giant is a very powerful and
extremely quiet pump, it does add a degree or two of heat to the water
temperature. I believe a good inline pump would reduce this side effect.
Other benefits of the inline pump are that a smaller resevoir can be used
and more mounting options become available.

2) Install a piece of clear tubing “sight glass” by using 1/8″ barbed
fittings on the side of the resevoir. This would allow the fluid level to
be easily checked at a glance.

3) Use screws for attaching the heatsink/waterblock to the CPU cartridge.
Using the standard metal clip affair does not guarantee uniform pressure of
the heatsink/waterblock to the CPU slug.

4) Experiement with Peltier chillers either on the radiator or in the

Phase change cooling is the next thing to try once I muster the motivation
to commit to the project.

From: David (no mail address)

I’m using a heater matrix from a car as a radiator.

All I had to do was zip-tie 2 80mm sunons onto it and it works a treat!

They cost about $30 but I got mine for free because the guy in the store had no idea what car it fitted 😎

The 1/2 inch pipe I use fits on tightly. I had to heat the pipe up in some boiling water to make it soft enough to slide on, then I secured it with a clamp.

From Ron Dy Geronimo

I chanced upon this very interesting radiator from a junkshop. It was from a motor scooter, 20x17x7 cm, copper tubes, aluminum fins.

The copper tubes are thin, to minimize the thermal resistance associated with thick walled tubes.

It also has these wavy copper strips inside the entire length of each tube. I figured that the “waves” cause the water to hit the walls instead of flowing just right through; and this action allows more heat to be transferred to the copper tubes.

Something else that sets it apart is that water flows through the tubes in parallel, unlike those with a single continuous tube, which translates to less drag.

This unit replaced my old car aircon evaporator “radiator”.

From Fred Buckner

I made a neat radiator from a aircondioner radiator: all aluminum, double row 3/8 tubing. I cut a section out the size I needed to fit in the case, about 5in.x5in..

One end was left with the factory loops all closed. On the other end I left the top and bottom tubes open, closed the remaining tubes with 180deg. loops cut from the left over end on the radiator .

I stretched the open tubes on the radiator till the loops would just slide inside and mixed up some J.B. weld secured them.

The aluminum tubes stretched easily with a brass fitting ground down and just tapped in. I am using a 120mm. 120v. fan in the front of the case with the p/s fan and a 80mm exhaust fan blowing out the back. Two 120v lighted rocker switches on a bay bus for the little giant pump and the 120v fan.

P.S. the A/C radiator came off a junk Ford Escort and would make a couple more radiators and can be built to any size needed.

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