1993 GS300 Overheating

You've replaced so many things, I'd go with the process of elimination and suspect water pump. It might be moving enough water at low engine speeds that, with the help of the aux cooling fan, it is able to cool, but at high engine speeds where the aux fan doesn't help, it needs a high flow rate and it simply isn't moving enough water.

How many miles are on the car? I believe at 90K you're supposed to replace the timing belt and typically the water pump is done at this time too. If the pump is original, it's probably overdue.

- Mark

Like Mark said...replace everything!!!

how much does a water pump usually cost to replace for the GS300? what about the ES300?

My car has around 60,000 Mile. The water pump looks ok, no leaks also I saw its performance through the return hose, not bad, but at high engine speed who knows! Can a water pump be bad and not leaky?

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Typically they leak when they go, but after ten years, who knows? For example, you may have a impeller cracked or broken which could be causing a restriction. It wouldn't be my first thing to replace, but you've already done about everything else.

- Mark

I took it to Lexus dealer and, they repaired it, they said it was one of the bypass hoses which was chocked, so now I knew that the car has more than the upper and lower hoses for coolant. Temperature gauge is now back to normal (less than 1/3), thanks guys for your contribution.

Glad to hear it is fixed. Be happy that the bypass hose did not break on you.