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Re: Unable to Solve Overheating 4000q

I had a similar problem with my '87 4kqs right after I bought it.  I
changed out the sensor that reads the water temperature and it returned
to normal.  It's not too expensive, you might want to swap it out to see
it it's just reporting the temp wrong.


C1J1Miller@aol.com wrote:

> <<<<<My 86 4000csq is running very hot.  Naturally, the first thing I
> thought
> it
> might be was the thermostat, so I put a new one in.  This didn't do
> anything.
>  I then flushed the sytem and radiator using a good cleaner and
> descaler,
> refilled it with 50/50 mixture of coolant and wather.......still hot.
> I
> changed the thermo switch in the radiator for the fan, nope.......Got
> a new
> temperature sender and put that in.......nothing.>>>>
> *Check the thermostat you took out to see if it was opening up (put it
> in a
> pan of water on the stove and check the temp; when does it open?  I
> replaced
> a thermostat once on the 4000csq and the new one was crap.  Talk about
> doubting your diagnostic ability!!!
> <<<I thought too it might be the gauge, but the hot air blowing out of
> the
> vents
> is hot enough to burn your hand if you leave it there long enough so I
> know
> it's running hot.>>>
> *My '86 4000csq normally was above halfway on the guage; about 2 marks
> down
> from the top, it would turn on the cooling fan.  I also never had the
> oil hit
> the red zone on the bar guage.  Is this with the AC on?  That adds
> heat to
> the system.
> <<<Also, running on the open higway doesn't do too much to increase
> the
> cooling,
> the only major drop occurs when I am able to run down a steep hill for
> an
> extended period of time with the car in gear and the foot off the gas
> pedal.
>  After about a mile of this, the gauge reads down where it should be
> normally.>>>
> One thing I've heard of is that cheap aftermarket water pumps can
> actually
> slip (not the belt; that's the timing belt and toothed) with the
> pulley
> slipping on the shaft.  That means the engine may not be getting
> coolant
> passed through it properly.  Even if it's not slipping, which is
> somewhat of
> a long shot anyways, you could have some crap up in the block or at
> the
> waterpump that is keeping the coolant from properly circulating.
> Also, does your cooling fan come on after shut down?  It should,
> especially
> if you're overheating.  Also check to see that you have proper air
> flow
> through the radiator (no leaves & junk (or squirrel nests?) blocking
> it; the
> upper cover on over the radiator; the side cover by the radiator, and
> even
> the lower cardboard cover under the radiator.  They all aid in keeping
> the
> incoming air going through, not by, the radiator.
> <<<Does anyone out there have any ideas? Thanks for your help!
> Larry Smierciak
> 86 4000csq>>>>
> Hope this helps
> chris miller, windham NH  c1j1miller@aol.com
> http://members.aol.com/c1j1miller/index.html