Throttle Body Removal

[james250]

I'm looking to remove my throttle body from my IS250 and although there are only 4 bolts, one electrical connector and two hoses, according to lexus tech manuals, to remove and re-install the throttle body apparently the coolant needs to be drained and re-filled afterwards. Is this correct? apparently there are 2 water by-pass hoses to the throttle body.

Also it mentions that i will need to install a new gasket to the intake air surge tank.

Can anyone kindly confirm this? I am assuming since the two hoses that connect to the throttle body are water related that they must be connected to the cooling system and hence opening it will either leak coolant or let air into the system.

[Multics]

I disconnected the throttle body from the intake plenum 2-3 weeks ago when I changed the spark plugs, I can't remember seeing coolant hoses.

If there are coolant hoses then you're right, you should bleed the coolant system afterwards, no need for a full coolant service IMO unless required.

I didn't change the gasket between the TB and plenum (forgot to buy it), but it still makes a very good seal.

[james250]

I disconnected the throttle body from the intake plenum 2-3 weeks ago when I changed the spark plugs, I can't remember seeing coolant hoses.

If there are coolant hoses then you're right, you should bleed the coolant system afterwards, no need for a full coolant service IMO unless required.

I didn't change the gasket between the TB and plenum (forgot to buy it), but it still makes a very good seal.

Thanks for your reply, i'm also thinking that draining an entire cooling system just to change the TB will be over the top. There are two small hoses and the lexus tech docs refer to these 2 hoses as the water by-pass hoses, so i'm hoping even if there is some coolant in there, I should be able to quickly swap over and then just bleed the system and add coolant if neccessary?

Do you know if the throttle position sensor and the idle control valves are both built into the throttle body? or are they seperately attached outside the throttle body?

What's the best way to bleed air from the IS250 coolant system? other car manufactures have some bleed valves at the highest points of the the in and out hose. I read somewhere that simply removing the radiator cap and letting the car run with heating on full blast should get rid of all the air. But isnt this dangerous? at what point do you close the cap?

Thanks

[james250]

anyone?

[Da e]

Can anyone tell me what the egr valve bolts down onto as one of the fixed bolts that I assume comes from the throttle body has sheered and wondering how this is replaced,it's the,one of two bolts that comes up through egr that secures the egr pipe down,please help!?

Edited November 25, 2019 by Da e
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