96 Nissan Sentra, Radiator diagnositics question

I have a 96 Sentra GXE with 120k miles on it. Recently, I have been
having overheating problems. I have a suspicion that my problems
derive from my radiator.

My radiator has its tubes travel vertically from top to bottom. As I
understand it, there should be a gradient of heat from the top of the
radiator to the bottom. In other words, the hottest part of the
radiator (at operating temperature) should be at the top while the
coolest part would be at the bottom. This gradient should be true
for the entire radiator with any "dead" spots. With my radiator, I
have found the following"

1. At the left part of the radiator (near the upper inlet hose), the
radiator is very warm and there is a gradient to the bottom.

2. The right half of the radiator is cool to cold. This is true from
the top of the radiator to the bottom. It is as if there were no hot
anti-freeze in this portion of the radiator. It would seem form this
that there is blockage preventing flow to that portion of the
radiator.

Is my theory right that what I have found is an indication that the
radiator has blockage?? I should mention that the radiator is the
original and approximately 9 years old.

Al Kondo

Your assessment is certainly a possibility, Al.
But as you have probably read on this newsgroup, there are lots
of possibilities that cause overheating.

First are you SURE the car is overheating? Inaccurate gauges
and faulty radiator caps can sometimes lead you to believe that
it is overheating when in fact it may not be.

Are the fans working? If not, or if they are working only sporadically,
then you may have overheating at times.

A partially blocked radiator or a faulty thermostat can cause overheating,
as can a collapsing radiator hose. A radiator shop can clean and repair
your radiator for a reasonable price IF this is the problem.

Next on the list is the water pump...Usually they leak when they fail,
but not always...Corrosion, impellor damage, etc can cause them to
fail where they will cause overheating.

Are you 100% sure you dont have an airbubble in the engine? This
often occurs when you lose fluid, change fluids, etc. The engine
must be full of coolant or you may get overheating.

The last likely causes are internal engine problems...warped head, cracked
head or block, or blown head gasket... These problems may show up
as loss of coolant into oil (or not), bubbling of coolant in radiator, etc.