Coolant question, reservoir empty...

Re: 1996 Honda Civic, 238K Km

Two days ago I've noticed smoke coming out of the hood near the
coolant reservoir. At first I thought it is because of the cold
winter (its below freezing temperature in Ontario). Then I smell
something different and pulled over.

I found the coolant reservoir near empty and so is the radiator (as
far as I was able to see). The spongy area near the radiator top is
full of coolant and smoke is coming out from that area. I did not
notice any change in temperature gauge while driving, though.

The area of the hose connecting the radiator seems to be a suspect in
my view although there is no apparent sign of leakage. There is no
residue under the car whatsoever.

Note: Yesterday and today I drove about 100km and noticed that it cost
me about 18-20 liter of gasoline which is very very unusual on my car
as the fuel efficiency is between 6 to 10 L/100km (Summer and Winter,
respectively).

I stopped driving it for now until I take it to a mechanic. I hope I
haven't damaged the engine by this time. Any thoughts on this? Thanks.

 

All the evidence is, as you suspect, that something failed
in the cooling system and you have a bad leak. Repairing
this could be cheap (like a new hose) or expensive (like a
head gasket).

But since it's Ontario and winter, and these Civics have a
tiny, roughly 1.6L engine, you may have lucked out as far as
damaging the car further, particularly since it was still
driving without (as far as you say) other indications, like
odd noise from the engine. The temperature gage may indeed
be reading accurately.

The whacko fuel mileage is likely due to engine control
system sensors not reading correctly, since many require
proper cooling from the rad system to work right.

 

Thanks Elle

Yes, there has been no other noise from the engine or anywhere.
Vehicle has been maintained (oil changed) at Honda dealership for the
last 2 years. In July this year, the mechanic suggested a coolant
change in Winter (now). All other areas including engine head area
(top area), transmission, etc are without any sign of leakage. And the
engine starts in 1-2 seconds in the morning (as it used to).

 

Wait, are you saying your mechanic did in fact change the
coolant recently? Wager there's a connection then. Hopefully
just an honest mistake. Preferably to no great detriment to
anyone.

A head gasket leak BTW would not necessarily manifest itself
with obvious leakage, other than reduced levels. The coolant
can get blown out the exhaust pipe in such situations.

 

No, the mechanic did said to change the coolant in this Winter. It has
not been changed. But now that the coolant is empty, it needs to be
changed/filled.

Ya, I booked an appointment for tomorrow to do some testing (pressure
test, head test and/or another test I forgot).