Overheating

  • Thread starter Thread starter Tim McNamara
  • Start date Start date
T

Tim McNamara

My 1990 240 overheated yesterday, the needle just climbing to the bottom
of the red zone on the temp gauge in stop and go traffic. On the
highway at 60 mph the temp would drop down almost to normal. When I got
home I looked under the hood and saw indications of boiling coolant in
the overflow reservoir. The car ran just fine. Coolant level is at the
minimum mark on the tank.

It's been running just a bit warm when the air temps is above 80F. My
guess is plugged up radiator. Goes into the shop Monday AM.
 
Tim said:
My 1990 240 overheated yesterday, the needle just climbing to the bottom
of the red zone on the temp gauge in stop and go traffic. On the
highway at 60 mph the temp would drop down almost to normal. When I got
home I looked under the hood and saw indications of boiling coolant in
the overflow reservoir. The car ran just fine. Coolant level is at the
minimum mark on the tank.

It's been running just a bit warm when the air temps is above 80F. My
guess is plugged up radiator. Goes into the shop Monday AM.
Click to expand...

It could also be a failed fan clutch. The fan is supposed to freewheel
when cold and engage when hot. I'm not sure whether they used the
bimetallic strip or the fluid-type clutch on a 1990, but both are known
to fail.

Bill
 
Tim said:
My 1990 240 overheated yesterday, the needle just climbing to the bottom
of the red zone on the temp gauge in stop and go traffic. On the
highway at 60 mph the temp would drop down almost to normal. When I got
home I looked under the hood and saw indications of boiling coolant in
the overflow reservoir. The car ran just fine. Coolant level is at the
minimum mark on the tank.

It's been running just a bit warm when the air temps is above 80F. My
guess is plugged up radiator. Goes into the shop Monday AM.
Click to expand...


Sounds like the fan clutch to me, I've also seen this on mine when the
wire came off the switch for the electric aux fan on the front, I'm not
sure if the non-turbo cars have that though.
 
migh be a failed cap on the coolant tank also...drop by your local
volvo shop
and have them pressure test it w/the proper tool...if it won't hold
the pressure...the
coolant will "blow" out of the system....The coolant system depends on
a certain pressure level......This happined on my s80 last month...$5
cap...
replaced...all is well....
 
Bill Bradley said:
It could also be a failed fan clutch. The fan is supposed to
freewheel when cold and engage when hot. I'm not sure whether they
used the bimetallic strip or the fluid-type clutch on a 1990, but
both are known to fail.
Click to expand...

Ah. Something else to consider and would be in keeping with having
decent cooling at highway speed and poor cooling in stop-and-go traffic.

What would be the effect of this on mileage? I've been getting great
mileage lately.

I'd pondered installing an electronic fan conversion a few times in the
past, hoping to improve mileage and responsiveness. Is this a
worthwhile conversion? If so, I might just go that route if it's the
fan clutch that's shot.
 
James Sweet said:
Sounds like the fan clutch to me, I've also seen this on mine when
the wire came off the switch for the electric aux fan on the front,
I'm not sure if the non-turbo cars have that though.
Click to expand...

No auxiliary fan on my car.
 
        It could also be a failed fan clutch.  The fan is supposed to freewheel
when cold and engage when hot.  I'm not sure whether they used the
bimetallic strip or the fluid-type clutch on a 1990, but both are known
to fail.

        Bill
Click to expand...

yeah; bum radiator would be opposite, overheats on the highway, cools
off when idling.
 
My 1990 240 overheated yesterday, the needle just climbing to the bottom
of the red zone on the temp gauge in stop and go traffic.  On the
highway at 60 mph the temp would drop down almost to normal.  When I got
home I looked under the hood and saw indications of boiling coolant in
the overflow reservoir.  The car ran just fine.  Coolant level is at the
minimum mark on the tank.

It's been running just a bit warm when the air temps is above 80F.  My
guess is plugged up radiator.  Goes into the shop Monday AM.
Click to expand...

My guess is a failed fan clutch.
 
Well, the mechanic checked it out and flushed the system, checked the
radiator, checked for pressure leaks, replaced the thermostat and
replaced the temp gauge sender as that's has always functioned rather
intermittently. It stayed in the normal range on the highway, in stop
and go traffic and while idling for the mechanic. I'll give it a good
run tomorrow.
 
Well, the mechanic checked it out and flushed the system, checked the
radiator, checked for pressure leaks, replaced the thermostat and
replaced the temp gauge sender as that's has always functioned rather
intermittently.  It stayed in the normal range on the highway, in stop
and go traffic and while idling for the mechanic.  I'll give it a good
run tomorrow.
Click to expand...

that mystery temp gauge board on back of the instrument panel can be
suspect too. sometimes even just the connections to it. when it goes
bad, you see huge temp guage swings at unrealistic rates of change but
the cooling system doesn't seem overheated.
 
z said:
that mystery temp gauge board on back of the instrument panel can be
suspect too. sometimes even just the connections to it. when it goes
bad, you see huge temp guage swings at unrealistic rates of change
but the cooling system doesn't seem overheated.
Click to expand...

With the old sender, the gauge tended to not work if the air temperature
was above about 55F- the needle just stayed at the bottom. Once in a
while it would come to life, such as in the recent overheating scenario.
In the winter it seemed to work fine. Today with new sender, I saw some
of what you are describing. The car ran like a top.
 
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