Hello all,
Driving older vehicles (by choice, mo$tly<g>) I keep a close eye out for
signs of leaks. My 90 Sentra has long had seeping oil leaks, so
intermittent drips of old crud don't scare me; if it becomes common, I
take notice, clear oil on the ground is a call to battle stations.
I have had the car since it was new, but the truck I bought just over a
year ago. In that time, it has barely made a mark on its part of the
driveway. I find this odd because it has some signs of minor leaks, but
I can live with it
Today, I started to leave for an errand and noted a fairly large wet
area under where it had been sitting; fortunately, I did not pass it off
as rain water. It was from the right side, and felt a little oily. I
hate to admit it, but my first reaction was "it's not coolant." A
flashlight from the top didn't reveal much. A little oily patch here or
there, but nothing scary, all consistent with the engine's normal
condition, and nothing that would explain the "spill."
I didn't see much from below, until what I now think was coolant dripped
on my arm, and I noticed the trickle leading back up to what I am
assuming is the heater core. The hoses inside the engine compartment
look fine. So far, I do not see any signs of coolant inside the cab; is
that something that I should expect to find, or does the cover arrange
for it to fall (forgive the ravings of a green mechanic) between the cab
and the wheel well, or something like that? Please feel free to correct
my anatomical references as appropriate.
The only other thing that comes to mind is that it _could_ be some dyed
fluid from the AC system. I doubt it, but I will mention it. The AC
was working fine recently, though I had no use for it today. I do not
know whether it has dye in it.
It appears not to leak very much when the engine is not running. Does
that tell you anything?
Assuming it is the core:
Haynes says to disconnect the negative battery cable. I'm happy to do
it, but am wondering why that would be necessary. There is also mention
in both Haynes and the Ford shop manual about vacuum connections. It
might make sense when I get into it, but any pointers to what is going
on would be appreciated. Partly curiosity, and partly wondering what I
am getting into.
Since the core seems a likely offender and apparently costs all of $22,
I am off to get one before it sells, and to have it on hand for when I
tear into it (probably tomorrow). With that said, is there anything
else you would consider as a source of the leak? My plan is to remove
the glove box and then put a pressure tester on it to hopefully prove
the core is the problem. Is there any problem with that approach? Does
removing the glove box ask for trouble with the battery connected? Any
other risk?
Haynes also says to drain the coolant. Again, no problem, but is it
really necessary? The heater hoses are high in the system, and can be
covered and supported high enough to prevent lots of coolant loss. The
coolant looks fairly clean after my relatively recent water pump and
radiator adventures, so I am inclined to avoid creating a lot of waste
just yet. It seems that I should be able to get away with losing only
what spills before I get control of the hoses and a little more
installing the new core. Please let me know if I am missing something.
Is there anything else I should be asking? You might recall advising me
on replacing the shocks, thermostat, water pump, and radiator.
Translation: I know just enough to be dangerous

Cautions and hints
will be gladly accepted.
Thanks,
Bill