93 Prelude SI using antifreeze. Help!

My son's 155,000 mile 93 SI has gradually been using more & more
antifreeze. It recently went through a quart in 600 miles. I have
thouroughly inspected for leaks and can find none. Water pump is fairly
new and no leak at the weep hole. No sign of antifreeze in oil, no foam in
valve cover. No sign of antifreeze in the transmission fluid. No smoke or
steam from exhaust. No antifreeze smell inside the car like a heater core
leak.

The only thing I see is a very slight greenish tinge on all 4 spark plug
ground electrodes. Is there a gasket some where or a known problem where
antifreeze could be getting drawn in through the intake tract? The car is
in great shape. I need to get this figured out before it gets worse.

 

Does the reservoir level climb when the car gets hot, then not come back
down again when it cools off? If so, blown head gasket.

 

concur with tegger. if you're sure there's no other leaks, it's head
gasket. in addition to tegger's advice, check for bubbling in the
expansion reservoir after the motor's at full working temp. watch it
for a while to be sure.

 

Check REALLY carefully. My own head gasket failure was in the very early
stages when I caught it. I had maybe one small bubble every ten seconds or
so appear in the reservoir. It will get MUCH worse the longer the problem
is left.

 

its gotta be leaking through the head gasket, and burning off. its just
not so bad that you notice it in the exhaust yet

 

My Civic FE project had a head gasket breach which led to overheating.
I opted to try an el cheapo block seal treatment which is described here:


http://home.earthlink.net/~honda.lioness/id17.html


As an update, still no sign of problems. Drove over one hundred miles
today in mid 90's Texas heat without incident.

JT

 

JT, what "el cheapo block seal treatment" product did you
use?

I have a friend with a 99 Civic with intermittent
overheating and intermittent loss of coolant. The level
seems to go up at times like Tegger said. Can't see any
bubbles in the reservoir. No suspect residue is on the spark
plugs or oil filler cap. (Plugs in fact look beautiful.)
Can't smell anti-freeze in the exhaust. But I also can't see
how it could be anything else. Been several weeks of the
overheating/loss of coolant problem. Pep Boys and dealer
have both looked at it and found nothing but likely did not
do a coolant pressure test; cylinder compression test; or
test for hydrocarbons in the coolant.

Her car overheated about three years ago when relatives were
driving it; a rock was said to have hit the radiator; they
didn't know it and so didn't pull over (yeah, I know...
slobs) before the temperature gage hit red. I figure a
breach began about then but hadn't manifested itself until
this particularly hot year hit.

I hesitate to send her to a block sealant product, since
rumor has it they often gunk up cooling systems bad. Told
her at this point best bet is to let a radiator shop
troubleshoot it. But I'll study the packaging of the product
you used and google on it and see if it seems worth a try.

 

CRC/KDS which is available at most autopart stores for under $10.

Follow directions except I doubled the running time and drying time.
And my car had bubbles in the coolant. I had problems after with
lowering coolant levels (air in the closed system) but that was due to a
crack in the elbow of the coolant recovery tank. JB Kwik Weld took care
of that and the system works perfectly now maintaining the coolant level
at exactly the "full" mark on the tank.

Overheating can also result from stuck thermostats or failing waterpump
though these are not typical on Hondas.

Extreme overheating loosens all the crud in the system ultimately
collecting in the radiator. Sounds like this may be what happened.

If no bubbles in the coolant, I would not suspect the need for block
seal. A clean system seems to be the need here...

JT

 

Right, but with the loss of coolant, ISTM she's looking at a
cylinder head cooling system breach.

The water pump was changed just a few months ago, during a
timing belt job.

Air purges have also been done. She with the shops has been
topping off the system as needed. Yet it won't stop
overheating every so often.

I will see when she last had a coolant change. Thanks for
the input.

 

My $0.02. Steam mixed with combustion gases can erode holes in cylinder
heads or any metal. I wouldn't leave this too long. Even if you are
putting in a quart every few hundred miles, the stuff that is leaking out is
up to no good.

Earle

 

Good advice. It will work on the valve seats first and then you have
problems.

Normally only impacts one cylinder, not all of them and that plug
should be fouling out. Do a compression check, see what you got. I'm
still suspecting it is getting out someplace else and you just haven't
found it yet.

Frank

 

Thanks, Earle and Frank. I urged her to address this and she
has mulled it over and says she is strongly considering
taking it to the dealer tomorrow. Her dealer says it can
check the chemistry and pressurize the cooling system
(presumably for a long period) blah blah to check for
leaking in the engine head. They are charging only about
$50. The dealer said they hesitate to do an engine
compression check when the leak is very slow; not a good use
of money. (You couldn't know how slow it is; just adding
this for the archives.)

 

One thing that can be done, is to pressurize the cylinders with compressed
air through the spark plug holes, and see which one makes bubbles come out
in the radiator. If you do this, be careful because the engine can suddenly
turn 180º in an attempt to relax the compression. It is good to pressurize
each cylinder with the piston down. They are probably right, that this
won't show up on a compression check, but it might show up as bubbles in the
radiator.

Earle

 

Thanks, Earle and Frank. I urged her to address this and she
has mulled it over and says she is strongly considering
taking it to the dealer tomorrow. Her dealer says it can
check the chemistry and pressurize the cooling system
(presumably for a long period) blah blah to check for
leaking in the engine head.[/QUOTE]

chemistry check = good, and probably the most reliable. but you can
smell the difference too. compare fresh coolant vs. stuff that's been
in a bubbly motor. the latter smells acrid vs. of the sweet smell of
the fresh stuff.

the problem with compression tests is that the engine needs to be fully
warm, and that can only really happen when the motor's running. it
needs the heat because the thermal expansion can mean parts fit at one
temperature, and not at another. unfortunately, hondas seem to leak
when full hot and not when below that.

 

friend's 99 Civic, displaying only a slow loss of coolant
and overheating (plugs look good, as does oil, coolant,
exhaust):

My friend had the dealer service department perform the
tests (not sure exactly which ones, apart from what I
described earlier as their saying they'd do). The dealer
service dept. said her Civic failed the tests miserably. She
had a new head gasket put in. Since she had the work done
there, she's pretty sure the diagnostics were free. Cost:
Around $950.

Moral of the story IMO: Never let your Honda's temperature
gage redline. It may take a few years, but it may very well
come back to bite you.

 

given the huge pita that job is, i'd charge at least that much!

that ain't necessarily so. head gaskets fail for many reasons, and only
one of them is being overheated. sure, overheating and possible warping
will definitely start the gasket on the road to ruin, but there's also
the mechanical loads caused by thermal cycling, corrosion and in higher
power use, because most honda liners are "unsupported", they can "walk".
i'm actually quite surprised by honda in this regard - i don't think
i'd use the liner configuration they do. aftermarket "closed deck"
inserts can be quite effective in this regard i hear.

 

Good advice for any internal combustion engine.

Earle