Here's the problem: I have an appointment *tomorrow* to drop the
car off to have the timing belt and water pump replaced, to take
advantage of a 2 week service sale. They will be replacing the coolant,
but I have to decide if I'm having them do the head gasket then,
obviously. BTW, the engine has always run perectly cool, even in very
hot weather, so I'm inclined to think the flow is ok...

On Feb 18, 4:20 pm, "mjc13<REMOVETHIS>"

low odds but this happened to me

i used some type of radiator additive that was supposed to kep things
cooler instead it made my honda go through radiator fluid and make me
think that i had a blown head gasket.  I would try to flush the system
first and start fresh. Next feel the upper rediator hose with your
hand after warm up. Do you feel fluid and is the hose good. Low odds
but upper radiator hoses can collapse internally and are soo tough to
diagnose.  Possible that the thermostat is sticking if no fluid
passing you have a problem. Next burp the system get excess air out by
adding water and squeeze the upper hose till bubles come out of the
radiator top fill hole repeat over and over till no more bubbles.

if still no progress either radiator shot, head gasket, water pump

start low cost and confirm all low cost items are good

When I had the oil changed in November, I was told they had to add
"quite a bit" of coolant to the reservoir. Since the car came from NM,
with a spotty service record, I had hoped that it was simply not topped
off ever. Now, three months later, with only moderate driving, I see the
reservoir is virtually empty again. I don't see excessive white smoke in
the exhaust, or smell antifreeze in it - although I haven't sniffed it
specifically for that, yet. The oil looks fine. I don't smell coolant
inside the car, either. It would be hard to spot a slow drip in this wet
Winter weather. How common are internal head gasket leaks in this
engine, as opposed to slow leaks in the reservoirs?