240 DL overheats badly

My 1980 240 DL overheats badly. Even in cool weather the needle begins
touching the read area when I drive over 55 mph. I have done a lot of
testing and some part swapping, but no success. Below are the tests I
have done.

Tests done:

- WATER PUMP tested O.K.: to test, I took thermostat cover off, took
the thermostat out, and cranked the engine, which produce a good
squirting.

- FLOW INSIDE THE ENGINE block O.K.: the above test should have prooven
that there is no obstruction in the water channels of the engine block.

- RADIATOR flushed and cleaned and tested O.K. (pressuring water into
any of the connectors will produce a good squirting of water out of all
other connectors; also, after driving, the radiator is evenly hot,
though cooler at the bottom, which should be normal)

- HOSES o.k.; top hose off of thermostat is quite hot, lower hose
feeding water pump is somewhat cooler

- FAN o.k.; creates good strong back flow

- THERMOSTAT is new
(also did an independent "thermostat test" in which I removed the
thermostat altogether, so that the flow (where the thermostat normally
sits) is wide open -- this had NO effect; still overheating)

- RADIATOR CAP is tight; system is holding pressure O.K.

- Exhaust is dry and clean, no smoke or steam.


Can anyone suggest any other conceivable cause of the overheating, and
how to test for it?
Thanks for your help and advice.

WOlfgang
Santa Barbara

 

Hi,
Is the car actually venting steam from the system ?

The gauge has a voltage regulator which can stop functioning and the
gauge tends to read peak temperature rather than average temperature.
Therefore it could be the gauge, but the radiator also becomes clogged up
with debris after 20 years of service and I had mine replaced on a 1981 240
Volvo.

cheers,
Paul

 

Since it does it at 55 mph, rather than at idle, we can assume it is more
likely a water problem rather than air flow. My prime suspect is the
radiator, especially if the coolant has been formulated with tap water
rather than distilled water. Flushes have never helped me in those
situations (and I used tap water in several cars before I learned), the
radiator had to be "rodded" at the least, or (if it is in bad shape) recored
or replaced. If the car has an auto tranny, most rad shops will recommend
replacement rather than recoring because the transmission coolant loop is
likely to fail soon afterward with bad consequences. Also if the tanks are
plastic rather than metal there is no point in nursing it any longer.

That said, ensure there isn't a blockage of the air flow anyway. Some people
have had a build-up of dead bugs and dirt nearly block the radiator fins
and/or A/C condensor fins. A strong spray of water from a hose, spraying
from the back to the front, has worked wonders for them.

Mike

 

Is the car actually overheating?
if not check the wire coming off the sensor is the insulation cracked &
brittle & the bare wire touching any metal close by?
is the temperature sender any good ?
If your local repair shop is not able to help you diagnose & repair then
you should try the dealer for a diagnose & possible repair
Glenn
Volvo technician
ASE Certified

--
"*-344-*Never Forgotten"
Is for the New York City Firemen who lost their lives on September 11,2001.
The official count is 343, but there was also a volunteer who lost his life
aiding in the initial rescue efforts. And I will never forget them as
long as I live,
nor should any American.
"Mow Green"

 

Sounds like a false positive. Probably the voltage regulator. The
gauges run on a reduced voltage somewhere around 5 volts. If the
voltage regulator is bad, the gauges will read around twice what they
should. The fuel gauge may be affected also, I am not sure.

 

Thanks for help

It works

after 2:30 the radio ask for the code

greetings Leo