Over heating please help

mellyb · April 9, 2018

Hi im new to owning a lexus. I have a is200 2002 manual. I was wondering if anyone can help, I had my car for a week,whilst driving it I noticed my temp gauge hit red then dropped right down to cold not able to stop straight away I had to drive it longer and it ended up with steam coming out of my bonnet/grill. Onced cooled I then had to fill the car with alot of water but manged to get it home fine and not over heating. Since then I have bought and fitted a new radiator as well as putting gasket sealer in the coolant and its still slightly overheating on the gauge and losing coolant but no steam. I have done a pressure test and thats fine theres no milky stuff in the oil or oil in the coolant im stuck as to why its still over heating. Iv bought a new water pump and new belt kit and belts that I need to fit. Does anyone have any ideas as to why its still overheating, its only overheating whilst stopped say in traffic or waiting but goes back to normal temp whilst driving.

Please help

steveledzep · April 9, 2018

Thermostat ?

gdh300 · April 9, 2018

Hi Melissa, welcome to the LOC.

I've no experience on the IS200 I'm afraid, but have you checked the thermostat and the fans? I guess as you have drained the system to fit a new radiator there should be no airlocks or blockages in the system.

Britprius · April 9, 2018

Not owning an Is200 I may be wrong, but this sound as though the electric cooling fans are not turning on while the car is stationary.

John.

Rebecca · April 9, 2018

Failed head gasket perhaps?

steveledzep · April 9, 2018

2 minutes ago, Rebecca said:

Failed head gasket perhaps?

That would show oil and coolant mixed.

Texas · April 9, 2018

Need to allow car to idle for a long while ( cabin heater on cold to assist ) to get engine upto temp and check that the stat is opening to allow coolant to flow to rad and get cooled and then later fan should kick in as there will be no cooling from forward movement.

check ( carefully) that all hoses you can get your hands on are getting Hot.

The symptoms you have are pointing towards a stat that is not opening fully, this can occur due to stat failure or if the incorrect concentration of engine coolant Is used and the stat gets corroded and sticks.

paul m.

usuf_x · April 10, 2018

As some have mentioned have you checked the thermostat?

usuf_x · April 10, 2018

sorry one other thing and this is from experience..............and not to scare you in any way but im not sure how the Lexus cooling system works however from my experience with Mercedes my coolant was leaking to god knows where (never heated up) and i finally found out that it was going via the gearbox oil cooler split that leaked into the gearbox..

mellyb · April 10, 2018

19 hours ago, Texas said:

Need to allow car to idle for a long while ( cabin heater on cold to assist ) to get engine upto temp and check that the stat is opening to allow coolant to flow to rad and get cooled and then later fan should kick in as there will be no cooling from forward movement.

check ( carefully) that all hoses you can get your hands on are getting Hot.

The symptoms you have are pointing towards a stat that is not opening fully, this can occur due to stat failure or if the incorrect concentration of engine coolant Is used and the stat gets corroded and sticks.

paul m.

Thankyou I have now bought a new Thermostat I'm gunna fit it with the rest of the new stuff on Saturday then I will let you know how it goes. 🙂

mellyb · April 10, 2018

3 hours ago, usuf_x said:

As some have mentioned have you checked the thermostat?

I have now bought a new Thermostat 🙂

ColinBarber · April 10, 2018

Check the cooling fans are working correctly.

m_co_0022.pdf

Magic7032 · April 11, 2018

Well I’m late to the party and only thought thermostat, and won’t hurt changing the water pump and belts as well I case the impeller has gone

what was the radiator like when you bought it, was it full? Mine was just full of water so I suspected a poor owner prior to me and changed everything (always planned too) and runs like a dream now

Rutlandlex · April 12, 2018

On 4/9/2018 at 10:52 PM, steveledzep said:

That would show oil and coolant mixed.

Not necessarily. The coolant could be going straight into the cylinder(s). I had that with a Subaru but the oil was fine.

Any update Melissa?

mellyb · April 12, 2018

3 hours ago, Rutlandlex said:

Not necessarily. The coolant could be going straight into the cylinder(s). I had that with a Subaru but the oil was fine.

Any update Melissa?

Hi I'm gunna fit all the parts on Saturday. I wish I stuck with my subaru impreza it was better. Will update when all fitted.

mellyb · April 12, 2018

On 11/04/2018 at 2:47 PM, Magic7032 said:

Well I’m late to the party and only thought thermostat, and won’t hurt changing the water pump and belts as well I case the impeller has gone

what was the radiator like when you bought it, was it full? Mine was just full of water so I suspected a poor owner prior to me and changed everything (always planned too) and runs like a dream now

Hiya I'm pretty sure it was correctly mixed water coolant. Iv bought the parts so thought I might aswell change them.

sorcerer · April 12, 2018

What made you go and buy a new radiator as a first step? Did you get a new radiator cap as well as the rad itself and did you check the integrity of the hoses, especially the lower radiator hose? If the lower hose is collapsing it can restrict the flow. Any white steam coming from the exhaust when the car is started after being sat for a while? Have you tested for combustion gases in the coolant?

Could possibly even be the heater matrix - are the front carpets wet? With the greatest of respect Melissa, you have to logically and methodically diagnose the problem rather than just throw money at it until all parts are replaced.

mellyb · April 12, 2018

4 hours ago, sorcerer said:

What made you go and buy a new radiator as a first step? Did you get a new radiator cap as well as the rad itself and did you check the integrity of the hoses, especially the lower radiator hose? If the lower hose is collapsing it can restrict the flow. Any white steam coming from the exhaust when the car is started after being sat for a while? Have you tested for combustion gases in the coolant?

Could possibly even be the heater matrix - are the front carpets wet? With the greatest of respect Melissa, you have to logically and methodically diagnose the problem rather than just throw money at it until all parts are replaced.

The radiator was leaking so it needed replacing and yes I got a new radiator cap to. Checked all hoses they all seem fine. Not got wet carpets. I had all ready bought the parts so I might aswell fit them as the belts really need doing anyway. And that's why I came on here to see if anyone can help.