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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

Reply to
mot12345
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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

Reply to
Dex

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

Reply to
Michael Pardee

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

Reply to
Glenn Klein

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.

Reply to
Stephen Henning

Thanks for help

It works

after 2:30 the radio ask for the code

greetings Leo

"Stephen Henning" schreef in bericht news: snipped-for-privacy@news.isp.giganews.com...

Reply to
Leo v. Ruyven

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