Overheating and Radiator cold

[youngoorah]

Hello everyone,

 

Just bought a 2008 Lexus ES350 with the 3.5l V6 engine, but the previous owner said that it starts to overheat, so I assumed that it was the water pump or thermostat since it has not been changed since new (currently sits at 175k miles). Symptoms that I am experiencing is that there's no heater, but if I rev the engine at idle the heat comes through, but when I start driving the heat becomes cold and I start to overheat. I just changed the water pump and thermostat with OEM parts and tested the thermostat as well in boiling water. However, before I did all that, I drained the radiator to see if the fluid was brown or if it was clogged. Fluid was red/pink and it drained just fine. Also have dealership records of it being services regularly with coolant drained and flush for about 30k miles or so. Burped the system, but still overheating, but the radiator was cold to the touch. I am at a lost.... Maybe I'm not burping it right? I unscrewed the nipple valve in the back and used no drip funnel with a tube that connects the two. I can't seem to get the coolant to come out in a solid stream (only air bubbles) but I kept the revs at 2-2.5k for about 15-20 minutes. I felt that its kind of long for burping? Please let me know. Thanks ya'll!

[RX400h]

Hello, Rick.

Over the last 20 years or so, purging air from coolant has (for some models) become more involved. Have you reviewed a Service Manual to see what steps are necessary?

[youngoorah]

I haven't read it but I followed car care nuts video on it. How long should burping take? Does what I did sound incorrect?

 

[wr989x]

I have the same issue with a 2007 ES350.  Was this issue resolved?

[RX400h]

Hello, Isaac.

Does your radiator fan come on when it is supposed to?
A blown head gasket could result in overheating. Also:

Quote

The radiator fan in your 2007 Lexus ES350 is designed to turn on to cool down the engine when it gets too hot, typically around 200 degrees Fahrenheit. The fan helps dissipate heat from the coolant circulating through the radiator.

The fan is controlled by a coolant temperature sensor and an electrical relay. When the engine’s temperature rises above a certain point, the sensor signals the relay to activate the fan².

If the fan isn’t working properly, you might notice symptoms such as the coolant temperature gauge frequently being higher than normal, engine overheating, or OBD II codes such as P0480.

It’s important to note that the fan might also turn on when the air conditioner is running, regardless of the engine temperature. This is to ensure the air conditioner can function effectively.

If you’re experiencing issues with your radiator fan, it could be due to a variety of reasons such as a faulty fan motor or clutch, a blown fan relay or fuse, or a malfunctioning temperature sensor. In such cases, it’s recommended to have your vehicle inspected by a professional mechanic.

Remember, driving with an overheating engine can cause significant damage, so it’s important to address any cooling system issues promptly