Engine Coolent Problems, I Suspect Thermostat?

[bebby90]

Hi all,

This is the first time ive created a topic, so hopefully i have started the thread in the right place.

Anyway, Ive had a 2000 Is200 Sport for almost 2 years now with no problems what so ever. Well until last week that was. I was driving to university( 4-5 mile journey) and noticed a slight billowing steam coming from the engine when stopped at the traffic lights, around 3-4 miles into the journey with the temperature guage pushing the red mark. I stopped and let the engine cool before continuing to university (late ofcorse). After lectures I lifted the hood and had a poke about and it would seem the engine coolent within the engine is not being cirlculated. At this point i was unsure of the cause, be it water pump, radiator leak, thermostat. I took a risk and drove it home in the evening after a few stops to allow the engine to cool.

Ive had another look today, started the engine to get the engine to operating temp. When the engine reaches operating temp i hear an odd clicking sound. I cannot workout whether this is the pump switching on but the thermostat jammed closed preventing circulation. Im unsire whether or not it is the water pump, or thermostat.

Can somebody confirm what the problem may be, im suspecting the thermostat & have ordered the part. I think i am going to take the opertunity to give the sytem a flush and refill.

Thanks in advance

Carlos

[sparkystav]

The water pump is engine driven so it doesnt click in and out, that might be the aircon pump?

the thermostat doesnt prevent circulation it mearly diverts the water through the rad to cool it when its hot enough

[bebby90]

Erm, well the clickingnoise has only begun since the overheating problem. So you would suggest the collent pump?

[ormi]

can you hear the cooling fans??thats the first place id look also do you know theit is two places to check the coolant

[Lance]

Are the cooling fans switching on? They are to stop the car overheating when sitting in traffic.

[bebby90]

No, i cnt recall hearing the cooling fans. Il turn the car over tomorrow and let it begin to go above half way on the temp guage and see if they operate, But the coolent in the radiator was cold so id not expect them to come on? It is as though the coolent within the engine block is not being released. Either due to the pump not pumping it or the thermostat blocking its exit perhaps?

[kenfoxy]

Sounds like the thermostat to me if the radiator is cold. Are you losing coolant? I wouldn't run an overheating engine in case it seizes.

[bebby90]

Well i toppedd the coolent up before my trip home from uni, suspecting a possible leak and when i stopped to give the engine chance to cool down i checked the level and it hadnt moved and also was cold.

I take it the thermostat is the unit at the end of the 2inch ish pipe coming out the top of the radiator to the right hand side (as you look into the engine)?

[Hill16]

Hi

Im new to all this moved over from Ireland just bought a Lexus is200 afew a weeks ago but it overheated last nite driving home there was no coolant so today I topped up the coolant and let the car run for about 30 mins fans all kicking in but coolant is bubbling in the sight gauge any ideas what's up don't want to go Lexus dealer because I would need to win the lotto to pay them .

Thanks in advance if anybody can HELPPPPP

[BenIS]

Could well be that the thermostat is siezed and not allowing the coolant to circulate into the rad, therefore not being cooled. If you have any mechanical know how id probably give that a go first.