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On demand cooling fan in GS300 MK-I?

With many if not most cars, I can hear a temperature controlled cooling fan start to run when I stop the car and switch it off. It continues to run for a little while. As far as I know, that is meant to ensure that the engine can slowly loose its heat after being stopped, because there is no longer air passing past the radiator (due to no movement) and the water pomp has stopped (due to the engine being stopped. This of course is all good and well and makes sense. However, I cannot remember having heard this on my 1995 GS300. AT least not for the last couple of years and perhaps not ever in the last 8 years that I have had it.

Does this car not have any temperature controlled auxiliary fan? Does it not need it?

I remember once or twice on really hot days, after a lot of stop and go city traffic, hearing the radiator (or expansion vat, didn't open the hood) actually boil after parking the car. That does not sound like it should be that way either.

Or is there perhaps a problem with a fan or sensor that is not functioning? No warning or CEL light and the temp gauge is always at just a notch below middle.

Thanks in advance for any insights.

Reply to
John Smith
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The electric cooling fan on the GS 300 does not run if the engine is not running.

Reply to
Ray O

Thanks for your reply. Your answer is definitely clear. Is there no risk of the engine overheating when the water pump stops while the cooling fluids are still very high? And I do wonder however what I should do whenever (if ever) I do experience boiling cooling fluid. Mind you, that has only happened two times in the past that I can recall, both times after a lot of stop and go traffic in the city, during very hot days. And that was before replacement of the radiator, that had been on its last legs for a while too, so that might have already been clogged up.

Thanks in advance!

Reply to
John Smith

When the temperature of the fluid is still very high, is what I meant to write, of course...

Reply to
John Smith

I suppose that in theory, the engine can overheat after the engine is shut off, but I have never heard of it happening in a Lexus.

The cooling system is pressurized so you should not be able to hear boiling coolant. If you can hear the coolant boiling, then there is air in the system and/or the radiator or radiator cap is bad. If the system is operating properly, after the engine is shut off, some coolant would circulate by convection and if the coolant is heated, it would expand and move into the overflow vessel. As the coolant cools down, the coolant is sucked back into the radiator from the overflow vessel.

Reply to
Ray O

Well, like I said, I do know that my radiator was on the way out already when that happened, so that will account for the boiling. Since the rad was just replaced (with timing belt which was ready to be replaced and thus water pump and serpentine while they were there anyway) I don't expect it to happen again. Thanks for your info. It is always a pleasure to read your comments and well founded insights here.

Cheers!

Reply to
John Smith

You're welcome and thank you for your kind words!

Reply to
Ray O

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