I have been having a strange problem over the past few months with
what appears on the surface to be my automatic Climate Control system.
The problem has become evident following an incident where the dealer
had put the radiator hose on upside down resulting in it abrading
against some mechanical part that wore thru the hose and resulted in
the vehicle overheating.

Whereas I previously had an automatic climate control system that I
kept at 72/73 degress most of the time, my A/C is now almost always
too cold no matter the inside the vehicle or outside temperature. It
immediately starts to blow cold when the vehicle is started and stays
cold most of the time unless I push the temp control up over 80
degrees.

The car never overheats and when I check the radiator and the hoses,
they are not overly hot to the touch. However, when I start to loosen
the radiator cap, there is not alot of pressure released.

The expansion tank has a level of coolant that is over the max line
and seems to stay pretty constant at that level.

I ran the engine wihtout the radiator cap on to try to get a sense if
the coolant was flowing thru the radiator but it was difficult to see
it moving. When I revved the engine, it did bubble up quite a bit.

I had thought maybe there was an air pocket that needed to be cleared
out so I removed the cap off the air release tube (not sure exactly
what it is called) but when I did a great amount fo coolant shot out
of the radiator.

Given that the climate control works (as I understand it) by mixing
warm air with the A/C cold air to get to the desired temp, my first
thought was that the thermostat is stuck open. However, the car (as
far as I can tell looking at the temperature gauge) warms up to normal
operating temperature so it does not appear to be the thermostat.

I have the vehicle going into the dealer next Monday but since I
wanted to take the Pathfinder on a trip from Pennsylvania up to Boston
this week so I have been looking around the internet looking at
symptoms and answers but have basically found nothing. I started to
entertain the possibility of replacing the thermostat myself today but
figured I didn't want to get into something I wasn't entirely sure of.
The dealer didn't seem to think that I would have any issues taking on
the 6 hour drive but I'm still a little uncomfortable so I'll probably
be taking our Saab instead, even though it is a little smaller inside.

Any insight or help as to what the problem might be would be greatly
appreciated.

TIA

Interior and engine temperature are mostly independent of each other.
I say mostly because I offhand can't think of a way they are related
in normal operation (a really smart system would, faced with an overheating
engine, turn off the AC and turn on the heater. But it would be full
blast, not what you describe).

Look at the Climate Control system, not at the engine cooling system.

"Zack Kennedy" <zackk (AT) treetop (DOT) com> wrote