Keep Your Cool
Cooling has been an ongoing issue for our classic and custom automobiles ever since we’ve been playing in that arena. The issues can be resolved with high dollar radiators, super pumps, shrouds, and any number of snake oil deals.
Now
the facts:
There
are several things that need to be done to insure proper cooling of your
automobile.
But first..............
1.
You need
coolant in it. Yep.
Plain water cools better than a 50/50 mix of antifreeze
and water. Debug your cooling system
on plain water (fixing leaks, trying different thermostats, etc.) and then, when
it’s all working properly, switch to half water and half coolant for
protection from freezing OR to 25% antifreeze if you want your engine to run
cooler and still maintain some anti corrosion properties in the system.
2.
FLUSH THE
COOLING SYSTEM. All of it!
The whole deal! Get a cooling system flush
product and follow the directions on the bottle.
A dirty cooling system, and that includes the block, won’t cool as well
as a clean one. That’s a fact.
3.
We need
to DETERMINE if the water pump is WORKING! Don’t
assume anything. Water pumps have a
problem with their impellers deteriorating.
You won’t know you’re missing an impeller or have a problem until
it’s too late. Here’s a simple
test. Remove the thermostat.
Bolt everything back together. Start
the car with the radiator cap off. You
should SEE water rushing past the radiator cap opening.
If you don’t then something is going on that needs correcting.
4.
Remember
that most cars really like a shroud of some sort that directs the flow of air
OUT of the radiator. That is, since
the fan PULLS air through the radiator you’ll be MUCH better off using a
shroud. You’ll want the fan about
2/3 of the way BACK into the shroud from the backside of the radiator.
This isn’t always possible but it’s good to get it as close as you
can to the 2/3 distance.
5.
Radiator
caps are important. Yep, they are!
Coolant at 16 pounds of pressure has a higher boiling point than coolant
at 2 pounds of pressure. Laws of
physics apply here. It’s not just
a good idea, it’s the LAW. You’ll
run cooler at pressure than you will with no pressure.
Remember to get the correct cap for your application.
You’ll not want to run a 16 pound cap on a system designed to run at 8
pounds.
6.
Running
your engine without a thermostat (with the exception of our test in #2) is
fallacy. An engine will run cooler initially without a thermostat.
After that IT WILL NOT! Why
you ask? Again,
physics. An engine running
without the restriction of the thermostat in the system (remember, even when
it’s wide open there’s still some restriction in the system caused by the
thermostat’s small opening) will not keep the coolant in the radiator long
enough for the radiator to ‘radiate’ the heat.
That is, the coolant must
stay in the radiator for a certain amount of time to dissipate some of the heat
it has absorbed from being in the engine block.
The coolant is in the block. It’s
hot. It moves to the radiator and
gets rid of some of the heat. If it
moves through the radiator too FAST, without the restriction of the thermostat
body, it won’t get rid of as much heat.
Thermodynamics R Us.
7.
The lower
the temperature ‘setting’ or rating of the thermostat the better?
Perhaps. It’s easier to
keep an engine cool than it is to cool it after it’s hot.
If we can get our engine to run along at 180 degrees (82 degrees C)
then we’re happy as clams. The
reality is that we will want the engine to run there as an average.
It’s going to run warmer in traffic, stop and go, than on the highway.
Seeing 190 in traffic is fine. Seeing
180 on the road is peachy. Running
at 150 is too cool. Generally,
engines
prefer 180 or so. Arguably 180 is
about nominal. Newer engines run
around 200 to 220 or so but that’s not where we want our street rod (unless it’s an
L1 crate engine or the like) to run. Our
TR6 is very happy at 170-180. The
Spitfire will like running around the same temperature.
Your small block Chebby or RB 440 Mopar will be joyus if you set it up to
run around 180 degrees.
8.
A 160
degree thermostat is probably a good place to begin.
That is, the thermostat will open when the coolant temperature reaches
160 degrees (71 degrees C). This
allows the coolant that is “trapped” in the engine block to start to FLOW
through the radiator and have it’s heat removed.
If you watch your temp gauge carefully you’ll see, just as you reach
160 degrees, the temp will DROP 5-10 degrees or so.
That sudden rush of cooler liquid that’s been sitting in the radiator
will drop the temp a bit. Of course
it will go back up as things run along but that’s normal.
If you wish, you can test your new (NEW) thermostat by putting it in
water on the stove. Use the candy
thermometer to see at which point the thermostat actually opens.
A new, 160 degree thermostat will open within 5 degrees of it’s rated
temperature (usually right on the number).
9.
Snake
Oil, or making water more wetter than it comes from the factory. Does this stuff
work? Depends on who you talk to.
Some people claim there’s nothing to it.
Some people claim it’s the bee’s knees.
I’ve never used the stuff and, therefore, have no basis for comparison.
Try it if you like, don’t
if you don’t. A properly
functioning cooling system won’t need miracle chemicals to make it work.
If it’s broke you’re not going to fix it with different chemicals.