over heating issues

[snoik]

Hi All,
Any idea's, My 97 TJ is having issues, when driving slowly in the scub everything seems fine, but when on the open road the engine runs hot, hot enough to bring the warning light on, I have mounted a winch on the front bar and thought this maybe restricting the air flow( but other TS's have them) I also replaced the original radiator with a 3 core unit, but still the same problem, what's next ??????.

cheers
snoik

[85cj7]

Air flow or restriction is not the problem because as you mention the temp is fine at slower speeds and only begins to rise as the speed and thus RPMs of the engine increases. The radiator is also sufficient because of adequete cooling at slow speeds. I would replace the thermostat for the peace of mind and the probabiity that it is stuck closed thus causing the engine to overheat at higher RPMS.

[snoik]

thanks, that was to be my next move, hopefully that's all it is,

[Steve F]

Could be a few things at higher RPM. Partially blocked radiator, dodgey hose that is collapsing at higher RPM and blocking the flow or worst case scenario would be blown head gasket or cracked head, you'd get some smoke (actually steam) out the exhaust at speed if that was it though.

Cheers
Steve

[Hunno]

partical blocked water jacket not cooling enough when heating up under higher rev's