Car: 1999 Honda Civic CX (Hatchback)
Location: Southern California
Symptoms: Sweet smell when I started the car Monday morning. Thought
my daughter had dropped some candy or something and ignored it.
Tuesday afternoon, while driving up a hill at ~50mph, I noticed the
engine temp gauge needle rising pretty quickly. It got about 3/4 of
the way to the top while I was looking. I was in the process of
slowing down to make a left turn, so took my foot off the gas and the
needle went down as well. Made it back home driving very slowly, and
the needle never went above the halfway point (but it was still above
where it normally rests). When I got home, checked the oil level
(fine), coolant (near max) and if the rad fan was obstructed in some
way (it was fine). Drove normally to the dealership after about 2
hours, and the temp gauge needle was at it's usual spot just about the
Dealer diagnosis: Don't know why it over-heated, but the head gasket
is blown. They plan to replace the head gasket, get the head checked
and machined and put it all back together again.
Questions: What are the likely reasons for having a blown head
gasket? Is it just age as the service person suggested? If they don't
fix the underlying reason, how likely is it to happen again? And how
long for it to happen?
Is it worth looking at putting in a replacement engine? I don't
particularly care for speed/hp as long as it's smog-legal in
California. But it would be nice to have something better than the
stock CX engine :) Are there any recommendations for mechanics in the
San Diego area who could do something like this? If I decide not to
take up the dealer's offer, will it be safe to drive the car to a new
Thanks very much for the help.
The head/block are likely to warp. But are they out of spec? Checking
the head is easy with a precision straight edge and a feeler gauge.
If you have extensive damage it can cost you, but maybe you don't??
Basic HG replacement should be no more than $800. I'm sure Honda sends
it out to their local AERA member and slap on a big profit for
themselves. ;) ;) ;)
Look up http://www.aera.org /
Click on the red "Find an AERA member shop in your area".
See if you can get one to check on your car at the dealer. And ask
about warranty. If you need a replacement engine, check Marshall or
Jasper Engines for availability. These usually come with 3-year/100K
for that kinda bucks i'd go with a low mileage junkyard engine.
swapping an engine is a no-brains affair, compared to the things that
could go wrong with the head gasket fix, sometimes not until quite a
while later when you can't collect on the warranty. even a warped head
will seal with a new gasket, for a while......
PS last time i got a quote from a dealer for a head gasket, they told
me $3K. even $1700 is too much, unless they do some head work at the
same time. anyway, that's why my civic now has a used B16 engine.
gauge can't be trusted unless it's in the red - it's non-linear.
think very carefully before you allow them to machine the head.
1. it probably isn't warped, thus is unnecessary.
2. in shopspeak, it does more for convenience, i.e. no difficult time
consuming cleanign operations, than it does for mechanical necessity.
3. they're hardly ever finished to the standards necessary to seal
aluminum properly, i.e. last as long as oem.
4. it affects valve timing.
5. it affects compression.
cracked radiator in the recent past.
if the head is "machined", it'll last just long enough for you to sell
the car. which is the typical exit.
yes. i'd do jdm or domestic [low mileage] used, NOT rebuilt. rebuilt
is only ok is you don't care or if you know a /REALLY/ fastidiously anal
builder, but they're rarer than rocking horse shit. typical rebuilds
rarely last anywhere near as long as the original engine. lots of
technical reasons that i cant' be bothered to list right now.
you can pick up used cx engines real cheap. tuners throw them away when
they upgrade civics.
Maybe so, but my infrared thermometer tells me the gauge is awfully good
at informing you of overheating well BEFORE it gets into the red.
With a 78C thermostat, you're expecting about 205F at the upper rad hose
inlet at the head. As the gauge begins to climb above its "normal"
position, the temperature at the inlet will climb to well above 205.
Bottom line: Ignore the gauge at your peril! Once it lands in the red, head
and block wapage is a virtual certainty! Catch overheating early and no
harm is done.
I'm going to assume this image is accurate, since I have no evidence
In any case, the apparent buffering or non-linearity does not matter. A
cooling system in good condition will handle about 235F before the fluid
risks bursting into steam.
If the gauge needle gets just a bit past half-way, the "sweet spot" at the
upper rad hose inlet will show...just about 235.
The point is that you need to keep an eye on the gauge all the time. The
gauge /is/ a very accurate tell-tale of a situation that may lead to severe
engine damage, even if it can't give you /exact/ information.
If the needle starts to rise, TAKE ACTION AT ONCE. DO NOT ALLOW THE GAUGE
TO APPROACH THE RED LINE.
The further from the red line you can keep the gauge, the greater the
likelihood that you will prevent the engine from getting wrecked,
regardless of any (im)precision inherent in the gauge itself.
Usually the head gasket is gone well before any symptoms surface.
People often notice once the car starts overheating after extended idling
in heavy traffic, or they notice the fluid reservoir level is WAY high,
with bubbles evident with the engine running.
Thanks all for the input. The dealer found no evidence of engine
damage. So it looks like I may have gotten lucky. But still an
expensive repair. I found an independent mechanic who will do it for
900, and that's most likely what I'll do. Still better value than
buying a new car. :)
Will keep you guys updated.
Two items that were not covered in this discussion...
1. Is this the original radiator, if not - How many miles since the
2. You checked the coolant level in the overflow tank but did you check
the radiator itself?
Original radiator. And still in good condition according to the
dealer. All hoses are fine too. Their hypothesis is that the
thermostat went bad.
I did not check the coolant level in the radiator. But because of the
sweet smell the day before, I am pretty sure the gasket was gone
before I noticed the overheating. :(
Does that change anything?
if the thermostat goes bad, the gauge will show. if the coolant level
drops, the gauge frequently won't. as grumpy says, with the engine
cold, you need to regularly check coolant level in the radiator, /not/
the expansion reservoir - any leaking means the bottle stays the same,
but the coolant in the radiator disappears.
Good call. The last time I checked the radiator itself was about 4
weeks ago when I did an oil change. It was fine at that time. And the
dealer said the coolant level was fine when they checked it. They also
couldn't find anything wrong with the thermostat, but suspect it was
stuck at some time, which may have caused the damage. This would be
the original thermostat. How long are they expected to last?
I dunno. It seems like the head gasket just gave up the ghost because
of age or something. Do they have an expected life-span?
Sort of. At /minimum/ you're expecting over 200,000 miles from a head
It's normally the "fire rings" that fail on an all-aluminum engine. Those
are the parts of the head gasket which keeps combustion gases inside the
cylinders. The fire rings can only take so much pounding over the years
before they eventually develop weak spots that turn into gas-leakage
Overheating (or near-overheating) accelerates failure of the fire rings
through warpage of the head, as does corrosion due to neglected coolant
There are three things you can do to prolong the life of your head gasket:
1) NEVER allow the temperature gauge needle to rise much above "normal";
2) change your coolant every two years, even if it's the "long life" kind;
3) make sure your ignition timing is always kept spot-on (on cars with
And have the radiator serviced/cleaned (rodding) every ten years or 150K
miles. A partially plugged radiator will raise havoc with any cooling
system. As JB stated, thermostats should be replaced maybe every five
years and lastly, a faulty water pump should be considered. Sometimes
impellers can start to slip.
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