Volker Mann Posted August 13, 2004 Posted August 13, 2004 I have a 1994 Lexus LS400 which runs hot. Below 75 degrees it seems to run fine. Over 80 degrees with the air conditioning on it gets hot, but if I turn off the air, it cools down somewhat. It runs cooler on the highway. One mechanic took the thermostat out, but this did not solve the problem. Fans work, and fluid seems to be curculating. Our closest Lexus dealer is 100 miles away, and told us it is the waterpump, sight unseen.
wwest Posted August 13, 2004 Posted August 13, 2004 Fans work.........??!! At low speed and HIGH speed??
95LS400Bob Posted August 13, 2004 Posted August 13, 2004 "Cooler on the Highway" is air flow. Look at fan operations and air flow throught the radiator. A bad water pump would not cool it down on the highway. Also..get that thermostat back in. Never run without a thermostat as it also slows down coolant flow through the radiator to allow heat tranfer...which is what cooling is.
90LS400Lexus Posted August 13, 2004 Posted August 13, 2004 Absolutely- get that thermostat back in. Check the cooling fans. Like the others said- this could be your problems.
VMF Posted August 13, 2004 Posted August 13, 2004 gen I LS uses thermal clutch to control the fan rpm, its not electrical and you cant really control it. the hotter the engine the closer rpm number of the clutch fun would be to the engines rpm. i think this is an issue in your car. its not really hard to change yourself. just remove the radiator and aux belt and you will be able to unscrew it. you might actually be able to do it wihtout removing a radiator. also do a coolant flush, that would never hurt:)
VBdenny Posted August 14, 2004 Posted August 14, 2004 Bob made a very good call. Without a thermostat your fluid runs through the radiator so fast it doesn't have a chance to cool. You probably had a sticking thermostat and by replacing it you would most likely have solved the problem. The cooling systems on these cars are pretty bulletproof. My gauge never moves in the hottest or coldest of weather, rock steady. I'd certainly agree with flushing the sysyem at the same time. One other remote possibility is a restricted exhaust. This is very unlikely but it you hit a speed bump and crushed a exhaust pipe or something, it could happen.
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