I am new to both this club and owning a Lexus. I Just purchased the car with 120 miles, and everything seems to work great, except the engine did not come up to normal operating temperature. I took it to a garage to get the thermostat replaced, and now it overheats when there is a load on the engine. It seems that the coolant does not flow past the engine. If you rev up the car in park, the thermostat opens and you can feel the hose heat up. Just after getting the car up to highway speed does the gauge start to go past the center. If the heater is on, then the engine cools right off, If i feel the lower hose after overheating, it is cool. If I sit and give it gas while idling, the engine starts to cool, as the coolant flows through the lower hose. I had the radiator flushed out twice. Put a new cap on. Tried to burp out any air pockets. Just wondering if there are any other Ideas into what I should be looking for..

Thanks

 

What does it say on the work order from the garage? What exactly did they do?

 

The first trip:

They replaced the thermostat
flushed the radiator and replaced coolant

Second trip.
Flushed radiator with a hose through both ends. Used heavy duty radiator cleaner solution with water and let the engine run for a half hour. Refilled with coolant. Replaced with new radiator cap. Ran engine with cap of to ensure no air bubbles. In the garage it seems to work because you can rev up the engine and the coolant flows and the fans come on. It is only when getting to highway speed were the car starts to overheat. Unless the heater and fan is on. It blows very hot.

Thanks.

 

Brand of thermostat and radiator cap? Only OEM is worth a damn here. I don't know why they used a rad cleaner unless the system was indeed showing corrosion? Maybe they installed the 'stat wrong or used the wrong one. If it was my car I'd remove the thermostat to check for starters. For bleeding the coolant get a Lisle spill free funnel running just with the cap off is not the proper way to bleed air.

 

That is good advice. I know if the bleeder pin is not on top at the housing, then air can be trapped. I will try the funnel as well. Thank you.