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re: Unable to Solve Overheating 4000q
<<<<<My 86 4000csq is running very hot. Naturally, the first thing I thought
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
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
<<<Also, running on the open higway doesn't do too much to increase the
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
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!
Hope this helps
chris miller, windham NH firstname.lastname@example.org