1998 Toyota Rav4 Overheating issue....

1998 TOYOTA RAV4
92,000 MILES • 4 CYL • 4WD • MANUAL
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BEACHHUT3
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Argh!!! Please help, My RAV4 overheats when doing speeds of 100 kph+ but around town and even in traffic it seems to be ok, I removed the thermostat and tested in boiling water and checked with a digital reference meter for the open and close temperature. I have left the thermostat out for the time being as wanted to check for any system blockages... have flushed the system and still have the issue.. the only thing I think is there must be a restriction when water pumped at speed... possibly radiator needs changing??? Also recently the cooling fan stays on all the time the ignition switch is on, so any advise would be great.... Thanks
Aug 20, 2009 at 1:30 PM
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KHLOW2008
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Hi beachhut3,

When overheating occurs only at high speed driving, it indicates inefficient cooling and the most common problem is partially clogged radiator. Normal flushing by draining and refilling the coolant does not help.

Remove the radiator cap and drain the coolant slightly, sufficient for you to have a look at the radiator core internals with the aid of a torchlight. If sediments are present, the radiator core is partially clogged and you would have to service or replace the radiator.
Aug 20, 2009 at 2:04 PM