I just bought a 92 Civic 1.5L with 193,000 miles. It runs great when
the coolant level is full. However, after driving for about 30-40
miles, it loses enough coolant to cause the engine to overheat. There
is very slight evidence of white smoke exhaust, although it almost
undetectable. When I start it, there is the smell of coolant that
comes through the vents. I've replaced the thermostat, ECT sensor that
goes to the fan, upper and lower radiator hoses, and the radiator is
new. Does this indicate that I have a small crack somewhere in the
cylinder head? I've always thought that a malfunction in the cylinder
head would render an engine almost useless and since the engine is
strong (when not overheating), I assumed the problem was somewhere
else. If it is the cylinder head, which is the best route to take in
purchasing a new head: brand new or remanufactured? Thanks. Paul
A head gasket failure is more likely. The group seems to be
getting a lot of such failures due to the heat wave. Though
in this case, the person who sold you the car might have
Repair will cost around $500 to $1000 at a shop.
Do not drive the car. If it overheats too much, the cost of
the repair will rise.
No, it just leaks either coolant into the cylinders or oil
into the cooling system, or both.
Thus you can also check the appearance of the coolant (any
oil in it?) and oil (is it looking thick, like Wendy's
I'm guessing there is a warp of the head in conjunction with the bad gasket,
but the fix is basically the same either way: the head has to come off, be
checked and/or milled for flatness, and a new head gasket has to be fitted.
As Elle indicates, it is not just a possibility any more. The spraying of
coolant out one cylinder when another is pressurized is a positive
my position on head recovery is that if you have the luxury of doing the
job yourself, you get to choose what happens as a repair route. milling
it is not necessarily a good thing, and in my experience*, is sometimes
downright destructive for an aluminum head. the #1 thing is to *CHECK*
the head. if flat, re-use as-is [after cleaning up of course]. if
*slightly* warped, also check the block. if the two are "warped in
sympathy", do not mill the head! or at least, not if they're both
within the same ballpark of each other. flatness is easy to check with
a metal spirit level as a straight edge and feeler gauges to measure any
* aluminum castings like this gouge easily. depending on the milling
[skimming] operation and the tool used, a cutting edge can pick up a
piece of material in the casting, but instead of slicing through it,
push it all the way along the surface plowing out an increasingly deep
furrow as it goes. and these things can be real deep too. [no gasket
is going to seal for very long after that.] the cutting operation needs
to be high quality and appropriate to the material, leaving it with a
fine smooth surface. myth about "heads need a little roughness to
'bite' the gasket" are utter bunk. d.i.y. head finishing operations can
be done with a block of 6"x4" [or larger depending on your hand size]
x3/4" plate glass scrap and wet & dry paper. remarkable flatness can be
achieved with a little patience and a well distributed polishing
pattern. scrub thoroughly [with a scrubbing brush] with plenty of soapy
water at least twice to remove all traces of silicon carbide afterwards.
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