"Pete from Boston" > wrote in message
ups.com...
>
> Don R wrote:
>> Pete from Boston wrote:
>> > In the past two and a half years I've replaced my '90 Accord's
>> > radiator, water pump, thermostat twice, and just had the cooling
>> > fan
>> > motor and temp sensor replaced after the car started getting hot
>> > even
>> > while moving fast (without boil-over). Following that last repair,
>> > I
>> > had to drive the car 150 miles home, following which I smelled
>> > coolant
>> > and found a fair amount dripping from the radiator area while
>> > parked.
>> >
>> > The temp gauge reads low-to-mid-level, as it should, and the
>> > receipt
>> > says they did a pressure test (plus the mechanic said they'd idled
>> > it
>> > for 45 minutes to be sure the fan was working). So why the coolant
>> > spill? Any ideas? I don't know how pressure test and idle compare
>> > to
>> > real highway travel. I plan to call the mechanic when they open
>> > tomorrow, but any ideas from the crowd would be appreciated.
>> >
>> Could it be a head gasket leak? If combustion gases are leaking into
>> the cooling system it could be causing an over pressure condition and
>> forcing coolant out of the system. Just a thought.
>
> I picked up a pressure tester (gotta love Auto Zone's free loaners)
> and
> I'm going to run it tomorrow to see what I see. Any tips on what to
> look out for? I'm hoping I actually see a coolant leak. If it's a more
> complex situation (like the head gasket) I'm not entirely sure how it
> will pan out.
>

I'm not sure the pressure tester will show a head gasket leak. A better
test would be a compression test. If one of the cylinders is low that
would be a pretty strong indicator of a leak. There is also a chemical
test that will show when exhaust gases are present in the coolant. Not
sure how much this test costs, but I think it's on the expensive side
($90).
Try the compression test, it's cheap and fast. I suspect you will find
a low cylinder during the compression test.