1989 760 gle, 123,000 m

car looses the coolant somehow then overheats.
new tank cap, bottom radiator hose, fresh
coolant. seems to lose bout a half a tank full
a day. no drips on floor, no water in the oil.
as if something just sucks it out!!!
can it be leaking when driving and therefore
not noticed? this is makeing me nuts as i live
in las vegas and its HOT!! any help will be
appreciated.

Have you replaced the water pump and thermostat?

I had a similar problem on a Mazda. The car was in very good shape. Took off the water pump to replace it, and found that the impeller was COMPLETELY RUSTED AWAY! New water pump solved it.

The water could be going through a leaky heater core - you can block off the heater hoses with a couople of plugs to check that.

Otherwise, if it's not leaking out, it's going through a leaky head gasket into the combustion chamber(s). Run a compression check and a coolant system leakdown test.

See the FAQ for details on coolant losses. If you have the original radiator, heater hoses, and water valve, you are overdue for new ones.

Are you getting any white smoke out the exhaust pipe?
Are your carpets in the foot area of the front seats getting wet?
--
-------Robert, '93 940t, '90 240 wagon, '84 240 diesel (she's sick) , '80 245 diesel, '82 Mercedes 300SD

Have you chcked the radiator over for cracks in the plastic tanks?

Nick 1987 780 PRV 6 227350 Miles
SLC, UT
--
1987 Black 780 PRV - V6 224,746 miles

it looks like the radiator is metal on top
says "volvo" on a tag. is the the plastic one??

thanks for your help

doug

Here's a picture of mine. The side tanks are plastic. (they're usually black unless it's older and the paint has came off)
--
1987 Black 780 PRV - V6 224,746 miles

Here is a picture of mine. The side tanks are plastic (usually black unless it's older and the paints came off)
--
1987 Black 780 PRV - V6 224,746 miles